The Complete 1986 Back Issue Set.

Published each month by Frank Van Alstine of Audio by Van Alstine, Inc., 2202 River Hills Drive, Burnsville, Minnesota 55337 USA. Telephone 612 890-3517.Subscription price for 12 monthly issues is $16.00 per year plus $8.00 per year for foreign air mail. Annual back issue sets available from 1982 at $15.00 per year.© Copyright, Audio by Van Alstine, Inc., 1990. All rights reserved. No part of AUDIO BASICS may be reprinted or reproduced in any manner without the permissionof the publisher.

VOLUME FIVE NUMBER ONEJANUARY, 1986

Here we go again with another new year ofAudio Basics. Thank you very much for yourcontinuing support. We have more renewals,and have lost less readers this year than anyother. We now have all of you in our computerand hopefully, will be able to make addresschanges and renewal date changes quickerthan before. No, we won’t sell your name forthe Bill the Cat Christmas catalogue or for anyother purpose. We will be able to cost effec-tively remind you if you “forget” to renew,however, and to inform you if we have newproducts you might want to know about. Any-way, let’s get started with a new year.

One of my readers wrote me pretty disap-pointed about the T-60 power supply project.He “read” the article to mean that I recommendthe T-60 over any other turntable and thoughtI was abandoning the T-30.

He misread the article by reading betweenlines that were not there. I wrote the T-60upgrade project because the T-60 is a goodturntable, and there are a lot of them out therein service that can be easily helped. Our new T-30 package is still a better unit, is availablenew, and is lower priced. But, the externalpower supply helps the T-60 a whole bunch,and part of our purpose is to help improve whatyou may already own. That is the simple, andstraightforward reason for the project.

Many of you have asked me about improvingFM reception. I may have found an outstand-ing answer for many of you – the PARSEC7403-II amplified indoor FM antenna. Thislittle (16" high black “obelisk”) unit has a listprice of $75.00 and is available from Parsec,130 West 42nd Street, New York, NY 10036-7901, 212 302-4880, and is probably availableat an audio store near you (we are not stockingthem, yet).

It plugs into AC power and to your tuner, via a300 ohm matching transformer (supplied) ordirect 75 ohm F connector. I purchased asample because my daughter has terrible FMreception in her dorm room at Carleton Col-lege, about 50 miles south of Minneapolis (andnearly 100 miles south of the main Twin Citiesantenna complex). In a dorm room, there is noway to install an outdoor antenna, and with a“rabbit ears” she could only receive the two

local college stations cleanly, with noisy re-ception from a few of the stronger Minneapolisstations.

I tried the antenna in my own reference systemfirst, where I use a simple test clip for mostlocal stations and an attic mounted antennawhen trying for distant stations. Because of theorientation of my attic antenna, I get severemultipath distortion from one local stationand, with the clip lead, get noise on that station.

With the PARSEC, I was able to have my cakeand eat it – no noise or multipath on my“problem” station, and clean reception from asmany stations as my attic antenna. Also, be-cause the gain on the Parsec is adjustable, I wasable to “turn it down” to prevent overload froma 50,000 watt rock station a mile away from meand get less signal (and better reception) fromthat station than with a test clip.

At Carleton College, the improvement wasnight and day. Vanessa now gets 17 stationswith no noise at all, including all the importantMinneapolis stations, plus several from south-ern Minnesota and Wisconsin I don’t receivehere 50 miles north. The unit can be used as anomnidirectional antenna if pointed up, or as adirectional antenna if pointed towards the sta-tion.

There is another indoor antenna that appears tobe a clone of the Parsec, one called the TERK.According to reviews I have read, its perfor-mance is similar to the Parsec, and both mayhave a common origin (I don’t know the “poli-tics” of the situation). If one of my readers canfill me in, I would appreciate it. I have not“hands on” evaluated the Terk antenna. I doknow that the Parsec works very well for us,and may be a real problem solver for you.

One of my readers, Joel Witherell, writes me toask if I know if I.A.R. (International AudioReview – aka Wonder Caps, et al.) is still inbusiness. It seems that he sent I.A.R. $53.00for a two year subscription in April, 1985, andhas received only one issue and nothing else inthe past nine months. Again, can we get anyhelp out there? Thank you.

I would like to share a few more readers’ letterswith you.

Mike McGill writes, “Just had to take time towrite and tell you how much I am enjoying theSuper Pas Two and Mos Fet 120C purchased

last month. I am using the pair with a MagnavoxFD2040SL CD Player and a pair of RogersLS3/5A’s. I think even you might be surprisedat how loud the Rogers will play in my 13' x 22'room using the 120C. I don’t understand howthis can be a forty watt amp. The Super PasTwo does just what you said it would for myCDs. The DGs, Philips, London, etc. sound somuch better that I can listen much longerwithout getting fatigued. The Telarcs evensound smoother, by the way, I buy every TelarcCD I can get my hands on.”

Dr. Peter Johngren says, “Thanks for your fastservice, upgrading my preamp to a Transcen-dence PAT-5 Series Two and my amp to a MosFet 150C. The improvement is striking andvery much appreciated. I wanted to let youknow that you have finally done it; you havefinally managed to retire my equalizer! I usedto jack up the 16K and then roll off the trebleon the preamp in order to end up with lessnoise - that is no longer necessary with theSeries Two. What interests me more, however,is that I used to reduce the 4K sliders a lot, inorder to reduce a harshness, more noticeablewith CD. In fact, I thought I would eventuallyhave to retire my beloved Sony CDP-101. Withthe Series Two/150C combination, however,the harshness is gone on all well recorded CDs(all Telarc, ProArte, London, and most Philips)and greatly reduced on others. Any remaininghardness can pretty much be smoothed outwith the Treble control. How do you explainthis? Also, I no longer need to jack up the 30and 60 sliders to get that nice solid, tight bass- it’s there if it’s on the record. The net result,of not having to use the equalizer, is a moreopen, spacious, solid, gorgeous sound withoutthat slightly “pinched” quality that the equal-izer seemed to introduce. Needless to say, I amvery pleased. It was well worth the $450 for theupgrades. Thanks again.”

The following letter from Jim Willis is a bitlonger, but since he reinforces what I havebeen trying to tell you, and since I want you todo some of the system improvements I havebeen writing about, rather than just readingabout them (reading about simple system im-provements won’t make your system get betterby itself) I am reprinting his entire letter asfollows:

“Dear Frank: The purpose of this letter is torenew my subscription to Audio Basics, so

Audio Basics Complete 1986 Back Issue Set Page 2

enclosed is a check for $16.00. This has beenthe year where I have (finally) followed someof your advice, and boy, has it ever paid off!!!Here are a few of the Audio Basics tips I havefollowed, and what I perceive the results tohave been:

1. Installed a 10,000 ohm load parallel to myLonghorn Grado (instead of using a 30,000ohm circuit prewired for a Grace F9E orstd. 47,000 ohm). Also re-set-up turntable/tonearm/cartridge. Result: slightlyimproved bass, better imaging.

2. Installed TL071 op-amps on the phonoboards of my Super-Fet. (Note: Phonoboards only, as I didn’t want to mess upthe hard-wired ICs.) Result: slightimprovement in “listenability,” i.e., a littlemore musical.

3. Damped my turntable (FONS CQ-30/Grace 707) with four pounds of “Plast-i-clay.” Result: much improved bass,removal of a lot of the mud that I didn’teven realize was present. This was a bigimprovement, and I’m planning on addingseveral more pounds to the areas near theturntable.

The biggest improvement, however, was get-ting my Hafler DH-220 rebuilt into a MOSFET 200C. I am impressed. I had been listen-ing to the Hafler as well as a BGW 250B. TheHafler has more pleasing highs, and the BGWa more solid bass. However, both of theseamps are mediocre (at best!) when comparedto the MOS-FET 200C. The bass is astounding.It seems as if an additional 1/2 octave has beenadded on the bottom. (This through a pair ofMagnapan Tympani I(U)s that I thoughtwouldn’t play deep bass - wrong.)

The power of the unit (Mos Fet 200C) is alsoremarkable. On a whim, at one time I had theMagnapans bi-amped with 2 BGWs(mono) onthe bass, and the DH-220 on the tweeters.While this set-up sounded pretty average, itwould at least generate a lot of power (360watts per channel on paper). However, poweron paper was no match for the Mos Fet 200C,which is capable of driving the Magnapans tofrightening levels! I don’t see how someonecould possibly use more power with conven-tional speakers.

The Mos-Fet 200C is also a very listenableamp. The mid and high frequencies are cleanand very musical. However, I do have twocomplaints:

1. On many recordings (more than Isuspected) it has become possible to listento some pretty bad studio recording,mixing, and engineering. I had missed thisbecause of the “haze” provided by theprevious amplifiers.

2. It is now possible to hear the Magnapansmake music by shaking sheets of Mylarplastic. (I guess “mylar breakup” isMagnapan’s equivalent of “cone breakup”or “horn sound,” etc.)

Obviously, these complaints are not about theMos-Fet 200C. It is just that my amplifier is nolonger the weak link in my system. The problemnow is in the software and in the speakersystem. My 1986 hi-fi resolutions are:

1. Save money to upgrade to a Super FetTwo.

2. Buy a (Philips) CD player.

3. In the event of a windfall, buy some B&WDM3000s.

Thanks again for the audio advice as well asthe super new power amplifier.”

Thank you, Mr. Willis, for your kind anduseful comments. I hope they help motivatemore of my readers to actually try some of myadvice.

My biggest frustration in writing Audio Basicsis lack of response from many of my readers,and indications that you are reading it, but notreading it. I get too many requests to writeabout topics I have already covered in detail.(Back issue sets are available at $15.00/year.)I get many requests for troubleshooting help,but was told not to write any more aboutsystem troubleshooting in Audio Basics be-cause the subject is “too boring.” About a thirdof the subscriptions drop into a black hole,with no renewal and no feedback.

Letters like those above are what keep megoing. Without them, I would quit.

Enclosed with this issue is our complete new1986 product catalog. I would like to call yourattention to a few items:

1. The first go-around on a new faceplate forthe Super Pas Two was a failure. We gavethe sheet metal house “too good” data.Murphy struck! We prepared two mylarfilm sheets, the bottom with the engineeringdata and dimensions, the top with theactual artwork, each a registering film.When the artwork went to be photographedto make the etching mask for the faceplate,nobody noticed that there were twooverlaying films, the bottom one being theengineering data. They photographed thewhole mess (both films) and, theengineering dimensions were printed onthe finished faceplate. The workmanshipis lovely, the result is – do it over. So, newSuper Pas Two faceplates are still about amonth off. They will cost $40.00 (withnew silver knobs) and must be installedhere as we must do a LED swap, andunglue a few old push-on type balance

knobs without damaging the new balancecontrols. When faceplates are ready, wewill, shortly thereafter, be able to offercomplete brand new Super Pas Two units,as then we will be able to use new hardwarefrom S.C.C. (they are out of original PASfaceplates).

2. I am really pleased with the improvementsin definition and musicality I have recentlymade in our Super Tuner Two (can bedone with the original Super Tuner also).Those of you using our tuner circuit knowit is already the most musical soundingthere is. About 20 new capacitors, sometiming changes, and a careful re-alignmentmakes it much more transparent yet.Remember to pull your flywheel beforeshipping your tuner for a retrofit.

3. The new Transcendence 400 and 200 audioboards have been completed and producedand we are in production now. I havealready been called by one respectedreviewer (I sent him a “surprise” sampleT-200 Series Two) who told me that hehad expected a better amplifier, but not“that much” better! He said in comparingit with another amplifier he had then inhouse (noted for having excellentdefinition) that the “other amplifier” nowsounded muddy! The new TranscendenceSeries Two amplifiers are simply betterthan you can anticipate! They are deadsilent, have essentially no measurabledistortion, and are super transparent. Wehave “violated” lots of design rules. Theyare very high feedback units (try 200 - 300dB of feedback for starters) in a singleoverall loop. However, they have notransient distortion or phase distortion,and the feedback loop cannot overload.Otala said it could not be done. He iswrong. The units are absolutely stable tooand will drive any rational loudspeakerload. Output current is limited by thespeaker and power supply fuses within thelimits of the power supply capacitors andpower ratings of the mos-fets. Thus, youcannot expect to directly drive loads ofless than two ohms at high power, as thecurrent required will blow the fuses. If wedon’t use fuses, then many people woulddestroy their speakers under “party”conditions.

Here is the math of the situation. If ouramplifier can swing in excess of 40 voltsRMS into 8 ohms, then its power output isV2/R = 200 watts. This requires 5 amperesof output current. No problem, and our bigamps do this easily. However, with a oneohm load, the math starts to get to you.Assuming the same 40 volt swing (whichour big amps can still do if not fused), thepower into the load goes up to 402/1 = 1600watts (enough to fry any loudspeaker) and

Audio Basics Complete 1986 Back Issue Set Page 3

the current goes up to 40 amperes (80amperes for two stereo channels). Sorry,you simply cannot pull that kind of “juice”from a single residential AC outlet, letalone dump it into any speaker system andhave it survive. Those claiming high powerinto one ohm loads, and those producing“wonderful” one ohm impedanceloudspeakers, are simply “blowingsmoke.” And if you try it (with any brandof amplifier that does not have rationaloutput and power supply fuses) you willbe “blowing smoke” too, as your systemgoes up in flames. Believe the math, itsreal, the audio soothsayers are not.

The price of the Transcendence 200 toTranscendence 200 Series Two retrofit(all new audio circuits) is $400.00. Theprice of the Transcendence 400 toTranscendence 400 Series Two retrofit(all new audio circuits and many layoutand engineering detail improvements onmost older units) is $800.00. We can alsoinstall the Transcendence Series Twocircuits in old Transcendence 300amplifiers with excellent results but ittakes a lot of rewiring of the output circuits,as well as new audio circuits and thus coststhe same as re-doing the T-400, $800.00.In each case, the Series Two circuits arewell worth the expense.

4. We have made a running productionchange in the mechanical specifications ofthe Transcendence and Super Fet PAT-5Series Two models. The change, applicableto new units supplied by us only, is a newselector switch that occupies much lesschassis space. There are two reasons forthis change.

a. Most of you are using only onephonograph now, and are looking foreven more sets of line level inputs toaccommodate Stereo TV and VCRs,etc. The new switch changes thefunction of Phono 2 to an additionalline level input.

b. We will have another new productcoming (hopefully by this summer) –a dead silent and zero distortion,overload proof moving coil headamplifier. The new short selectorswitch leaves room in the PAT-5chassis to accommodate the new headamp circuits internally. It will beavailable as a separate package too.

I might as well tell you about a few more of ourupcoming plans too.

1. Assuming that we get past the “learningcurve” on the Super Pas Two faceplate, wewill offer a new faceplate for the PAT-5chassis too. That brings up a question –what do you want, silver with black

lettering, or black with silver lettering?Send me your “vote” before we get started.

2. We are also seriously thinking about a“Bridge” – a little box that will allow youto run any common ground power amplifier(including all of ours) as a double powermono amplifier without any of the nastyside effects (excess transient distortionand poor definition) of previous monobridged designs. We can do it, do you wantit? It will cost about $250.00. Let meknow.

3. Are any of you interested in aTranscendence Series Two IntegratedAmplifier (complete Transcendence SeriesTwo preamplifier circuits and a low

powered version (about 30 watts/ch)distortionless Transcendence Series Twopower amp circuits all packed into aDynaco SCA-50 chassis? I built one formy son for Christmas and got phenomenalsonic performance and outrageousdynamics for the power rating (it drivesthe B&W 808s just fine on digital material).It would cost about $1000. If there isenough interest, I will tool the newamplifier cards (my son got the hand etchedprototypes).

4. Finally, we can do a new Transcendence150 Series Two built into a Hafler DH-120chassis. It will be as clean as the biggerTranscendence Series Two amplifiers andmake about 70 watts per channel at zerodistortion. It would cost about $800.00.Does this excite any of you? Let me know.

No orders for these items yet please! Theyare not in production, just working“breadboards” that we can produce if thereis demand. Your feedback now will helpus to decide whether or not to go aheadwith them.

5. Now, what do you want us to do next? Gotany good ideas for a practical new productfor us? We are open for suggestions. Callme with your ideas.

How could Stereo Review have known aboutmy new B&W 808 loudspeakers when theysent me a renewal request containing the com-puter generated cartoon above? It fits the situ-ation, except I was able to get them inside (I

installed extra wide downstairs doors whenbuilding the house 20 years ago – good plan-ning). After living with the 808s for a monthnow, I want to tell you a bit about their “sound,”why they are important to us as a research tool,and why they will be important to you in thefuture as they lead the way to improved audioproducts and a much closer approach to reality.A couple of years ago, my brother-in-law (anon-audiophile) gave my best equipment aclose listen and asked me, “On a scale of 0 to10, how close do you think you are coming tolive?” It was a serious question, and I gave aserious answer, “A seven.” Last weekend, Pauland his wife spent an evening with us listeningto the B&W 808s driven by the big Transcen-dence Series Two equipment. He asked thesame question again. This time, the answerwas, “A nine.” We were playing a Neil Dia-mond CD at the time, at a sound pressure levelduplicating live concert conditions. Paul hadjust been to a live Neil Diamond concert. Hisresponse was that I was underestimating thesituation, as he could listen to Neil here with-out hurting his ears, but not at the live concert.We, and B&W, are making progress.

The greatest virtue of the 808s is not theirstupendous dynamic range, nor is it their awe-some range, bass response, and sheer bruteforce LOUD capability clean. Their greatestvirtue is their resolving power. They are sim-ply much more transparent windows to the liveperformance than anything else in existence.The additional 20 dB of dynamic range builtinto the 808s is best used to reach 20 dB furtherinto the reality of the music. Of course they areneutral, of course their tonal balance is perfect,that was expected. The excitement, the won-der, the awe of their performance comes fromthe purity and detail of these masterpieces –their resolving power. I heard the 808s last fallat B&W (on prototype B&W electronics) andwas immediately struck by their astonishingtransient performance. Signals that would sim-ply destroy other loudspeakers are played faith-fully, and startlingly, on the 808s. The demon-stration at B&W was impressive enough tocause me to decide to order out a set. However,I did not hear the best virtues of the 808 at thefactory – the definition there was simply ordi-nary. Imaging was ordinary too. In my studio,with Transcendence equipment (even withSuper-Fet and Mos-Fet equipment) that allchanges. Now the musical purity and realismof the speakers shine, and unlike Bert Whytethought in his Audio review, the 808 images ina realistically superior way too – a much betterthree dimensional sound stage than with anyother system I have heard, including 801s. Oneproblem, the 808s are so good that they aregoing to be the worst displayed loudspeakersin history. They will tell you everything that iswrong with the rest of your system. One B&Wdealer tried to sell a set to a client of mine,giving a demo so terrible (with McIntosh equip-

Audio Basics Complete 1986 Back Issue Set Page 4

ment) that the dealer explained that the 808s“boom too much” and that the client wouldhave to buy a McIntosh equalizer too, just touse them. The dealer was so stupid that hedidn’t know the boom was in his electronics,not the speakers. To be continued.

Frank Van Alstine

VOLUME FIVE NUMBER TWOFEBRUARY, 1986

We have got so many new ideas, improvedproducts, and so much work to do around herethese days that I really don’t know where tobegin this month. I guess I will start by tellingyou about a few new products and improve-ments to some old familiar ones.

B&W has just made two really nice improve-ments to their “low end” loudspeaker line thatmakes them better than ever, with no increasein prices!

1. DM110, 220, and 330 models are nowcoming with built-in 2 ampere quick blowspeaker fuses. The fuse holders are locatedin the input terminal tray on the back of thesystem. Although troubles with thesemodels are rare, the extra safety marginprovided by the fuses should make themmore blow up proof than ever. We arestocking a good supply of the special smallBritish sized fuses.

2. These same models have a new “open”molded plastic inner grill frame (insteadof a wood panel cutout for the speakeropenings). This new grill supporteliminates the diffraction effects of astandard grill frame and the speakers allsimply sound more open and spacious(and they were all very good before). Theylook sharper too.

The DM110 model ($300/pair two waybookshelf) is now the equal of the DM100in the middle and top, with better bassextension, and dynamics. So that while Ipreviously rated the DM100 as being betteroverall than the larger DM110, now Iwould rate the DM110 as being worth thesmall extra cost over the DM100. B&Wjust keeps getting better and better, andmore cost effective. If your driveelectronics are really good, there simply isnot any competition to them.

How many of you would be interested in mak-ing your standard line (DM100 throughDM330) B&W loudspeakers work a lot betteryet? Are you willing to “get inside” your speak-ers and rework the crossovers according to mydirections? If so, there are major improve-ments you can achieve yourself to the defini-tion and musical character of these models.

I became aware of the possibilities when aclient returned a set of DM100s to me to fix.There had been a “party” and the DM100swere fed the full continuous power of a 140watt/channel MOS-FET 200C until they gaveup and died. Talk about a wipe out! Not onlywere both woofers frozen solid, but upon fur-ther investigation, I found that all the cross-over capacitors were simply “blown up” too.They had been overdriven so hard that thecrossover parts had got so hot that they evenpartially melted the input terminal trays. Thiswas a real repair challenge!

Fortunately, it is rather easy to take B&Wloudspeakers completely apart, and after dis-connecting the crossover output leads from thespeakers, the whole tray can be “popped out”for convenient work on the test bench.

An interesting thought came to me while ex-amining the “remains” on the bench. Foreconomy reasons, B&W uses non-polar audioelectrolytic capacitors in the crossovers of thestandard line (not in the DM1200s and up). Bypure luck, the values they use were, in the caseof the DM100s, the same as I had in stock forour new Series Two electronics.

What would happen, I thought, if, when repair-ing these DM100s, I used our new high qualityfilm capacitors for the repair instead of origi-nal non-polars?

Note that we did not change to filmcapacitors throughout our new productline for any mystical or magical reason.Film capacitors do not, in and ofthemselves, sound better! However, a verycareful examination on our super-minicomputer did show us how one majorelectrical difference between anelectrolytic capacitor and a film capacitorcould cause “side effects” that would affectthe sound of the system. Simply, anelectrolytic capacitor, depending on value,has an internal resonant peak in the rangeof 30,000 to 50,000 Hz. A well made filmcapacitor “peaks” at a much higherfrequency – typically between 200,000and 500,000 Hz.

We have already shown that audio circuitsare not perfect critters, they generate theirown internal resonances under transientconditions (as do woofers and tweeters).Simply, by moving the resonant frequencyof the needed capacitors much further awayfrom the audio range, there is lessinteraction and IM “beating” between thecircuit and the passive parts. Distortionunder transient conditions is lower, Qs godown, and musical character is improved.Anyway –

I repaired the DM100s by using carefullymatched film capacitors (paired channel to

channel) (three capacitors per speaker required,a 10 µF, an 8 µF, and a 7 µF, all at 100 volts).I replaced the fried woofers (the original tweet-ers survived) and compared these rebuiltDM100s to my stock demo pair, first on whitenoise (interchannel noise from an FM tunerwith the muting off). The result on white noisewas interesting, and telling. The “new” DM100swere noticeably smoother. On music, the re-sults were the same. The rebuilt DM100s weresmoother, higher resolving, and best of all,showed a distinct improvement in musicalcharacter. This is a useful improvement.

I will, as soon as time permits, go through eachof the loudspeakers in the DM100 throughDM330 series and make these changes, takingcareful notes so that I can write up a detaileddo-it-yourself project for Audio Basics. I willalso order out the appropriate parts for theother models so I can offer you a parts kit(consisting of the properly matched capacitorsfor your unit) for a reasonable price – probablyabout $25.00 per stereo pair. Are you inter-ested? If so, let me know. Don’t order parts yet,I simply have been too busy building, testing,and shipping our Series Two electronics to getinto this project in detail at this time.

One reason we have been very busy is that wehave finished another new product – THETRANSCENDENCE TUNER. This one doesit all folks: digital readout, signal seeking, fivenon-volatile station presets, effective variablemuting, a volume control, headphone jack,mono-stereo switching, and sonic quality sim-ply unbelievable for a tuner.

The sonics are so outstanding we had to buildour own FM broadcast station to find out justhow good it is. We did this by designing pre-emphasis circuits around Transcendence linecards, feeding the output of a Compact Discplayer into these circuits, then into a Transcen-dence Series Two preamplifier for gain adjust-ment, and then into the external inputs of ourSound Technology FM alignment generator(which is actually a little very high quality selfcontained stereo FM station). We then fed theoutput of the Sound Technology into a 300ohm antenna (instead of directly into equip-ment on the bench) and “broadcast” the signalacross the lab into the new TranscendenceTuner prototype connected into my referencesystem.

The reference system, by the way, now con-sists of B&W 808s, two Transcendence 400Series Two amplifiers (bridged mono with aprototype Transcendence Bridge – 800 wattsreal per channel into 8 ohms!!) and a Transcen-dence Series Two preamp (along with aMagnavox CD player and our H-K T-30 phonosystem).

I connected an identical Magnavox CD playerdirectly to the system (through the tape inputs

Audio Basics Complete 1986 Back Issue Set Page 5

so I could easily A-B the Tuner with the CDplayer by simply pushing in or out the tapemonitor button). I used two copies of the sameCDs, with one playing in the Magnavox driv-ing the broadcast station to the TranscendenceTuner, and the second playing directly into thesystem. After setting the levels into the SoundTechnology for optimum broadcast withoutover modulation and adjusting the volumecontrol on the tuner to match levels exactlywith the directly connected CD, we sat down tomake a few musical comparisons.

The major difference is that there is no majordifference! In essence, our new TranscendenceTuner will play back with equal dynamic range,fidelity, musical character, resolution, and im-aging as the same CD source directly into thesystem. And since our reference system is farbetter in every aspect than any other homeaudio system, I have got to tell you the Tran-scendence Tuner is pretty awesome.

Yes, if you strain, you can hear on a direct A-B a very slight dulling of the extreme highs,and a very slight loss of “authority” on thedeepest powerful bass notes (keeping in mindthat the 808s will play bass notes clearly thatother speakers don’t reproduce at all). How-ever, if you come into the sound lab withoutknowing which is playing, you simply cannottell, in the absence of a direct A-B, whether itis “live or is broadcast.” On any lesser system,with a really high fidelity FM broadcast, theTranscendence Tuner will give away nothingto any other source you may use.

The Transcendence Tuner is built into a HaflerDH-330 tuner chassis. We have salvagedHafler’s digital and logic circuitry for out-standing tuning stability and “creature com-forts.” We re-engineered the IF section (youcan now tune it a full division “off station” andstill get clean reception), we optimized theoperation of the Hitachi IF-Detector and Mplxintegrated circuits, and interfaced brand newTranscendence Series Two audio sections (twocomplete new PC cards to replace one littleoriginal dual op-amp). We also installed a newpower supply board that does two worthwhilethings. First of all it supplies an independent +& - 15 volt shunt regulated and wide bandsupply for our new audio section (free of anylogic and switching trash). Second, it substan-tially stabilizes and improves the original rawpower supply to the rest of the circuits, provid-ing much better regulation for all of the origi-nal tuning and signal seeking functions. Wealso installed new high quality Switchcraftinput jacks. The only original function that hadto be discarded was the Hafler dynamic noisereduction board. This circuit just cuts separa-tion when things get noisy (a function the tunerdoes anyway with automatic stereo-monoswitching) so it is no great loss, since ourcircuits are quiet and sensitive in any event.Coupled with a Parsec or Terk antenna, you

should have fine reception (and amazing fidel-ity) in any rational location.

The price is $695.00 for a complete new unit,or $495.00 if you supply the Hafler DH-330assembled, and in good working order. Avail-ability? Right now! Allow 30 days for deliv-ery, we are running really busy.

How does it sound compared to our famous(and recently improved) Super Tuner Two?Like the difference between the Super-Fet Se-ries Two preamp and the Transcendence Se-ries Two preamp. Although the Super TunerTwo is widely known for the best sonic qualityout there, the Transcendence is much moretransparent and dynamic, and as mentionedabove, is fully equipped with “creature com-forts” (sorry we don’t have the micro-waveoven or coffee maker circuits working quiteright yet). Best of all, the Transcendence Tuneris available directly from us new (we are out ofFM-5 chassis and can only rebuild Super TunerTwos from units you supply). The Transcen-dence Tuner is simply a product no otheresoteric manufacturer can design! No matterwhat brand of audio electronics you like, youhave no other choice when it comes to FMreception, you need our tuner.

Hot flash! I discovered I overlooked anotherset of “SPARS” codes you should be lookingfor when examining Compact Discs to find outhow they were recorded. In addition to the[DDD] and [AAD] codes explained to you lastyear, there is another code – [EED]. Thisstands for, of course, Eight Track to EightTrack to Digital. Look for the great new CD,Slim Whitman’s Greatest Hits on this format inthe near future (not available in any store, callus now at 1-800- etc. and have your credit cardhandy). Just kidding, folks (I hope).

I investigated another audio cassette recorderrecently, the new Harman Kardon 192, andunfortunately, found it to be just another awfulJapanese “air pack” made in the same cassettedeck plant (apparently) as all the other crummycassette decks are.

It appears that all cassette decks are made inthe same place to the same formula. Stuff afancy faceplate on a big tin box, stuff an el-cheapo PC card full of trash in one corner, stuffa plastic $5.00 tape transport in the other cor-ner, tie the whole works together with a wad ofribbon connectors and cable ties, and write a$100 full color advertising sheet telling every-body how “wonderful and unique” it is. Sorry,the method and marketing is simply one biglie! This “brand new” Harman Kardon modelhas an identical plastic transport as mydaughter’s two year old Onkyo, yetch! Thefrequency response chart was drawn by thatsame elderly Japanese lady with a ruler andpen too (she is very good at it).

Essentially, H-K has attempted to “extend” thefrequency response of the unit beyond what itis capable of doing. It may “measure” flat tohigh frequencies, but it sounds terrible with a“ringy” and non-musical top, boomy bass (whatthere is of it – not much) and a sucked in mid-range. Not to pick on Harman Kardon toomuch, this is the way all “extended range”cassette decks I have heard in recent yearssound to me.

In contrast, the Sharp RT160S, (available atdiscount stores for under $50.00) is simply amuch smaller tin box (less air in the “air pack”)with a similar plastic transport and trash PCcard, but with much better sonic quality be-cause they didn’t try and make the unit do whatit cannot. It is a limited range machine, andwhat it plays, it plays well. Sure the highs aredulled and the bass is rolled off, but, themidrange is musical and the balance is good.The RT160 has one major mechanical im-provement over the previous RT100 and RT110models, a more reliable slip clutch (a realspring rather than a sliding rubber cogwheel)that will probably last much longer.

My observations on cassette decks have notchanged. There is simply no point in spendingover $50.00 on one, and the Sharp units areconsistently good sounding and good value. Ifyou want a “hi-end” tape recording format, geta Sony Hi-Fi Beta video recorder which willwipe out any cassette deck at any price. Audiocassette is simply a stupid format.

In general, the Japanese get away with sellingthis trash because the consumer does not un-derstand what “quality” really is! The market-ers have conditioned the public into thinkingthat high quality is nothing more than a goodexternal fit and finish and pleasing shape,together with a large helping of “features.”This sells millions of nicely finished “air packs.”They are selling you the “package,” the box itcomes it, not the product! They have got theconsumer thinking that a White Castle in astainless steel case (excuse me – a plastic casefinished to look like stainless steel) is better“quality” than a porterhouse steak in a papersack.

Take the cover off the package folks, lookinside, then tell me if the mass marketers aresupplying quality, or are simply selling fancywrapping paper.

The SUPER PAS TWO faceplate is finallyready! The metal shop got it perfect the secondtime around. The price is $40.00 installed,including return shipping in the continentalUSA for any Super Pas Two preamp we havepreviously built. The unit must be returned tous for the installation. The reason, because thisfaceplate specifically identifies unit as a SuperPas Two, it cannot go on any original SuperPas or stock Pas preamp as that could lead to

Audio Basics Complete 1986 Back Issue Set Page 6

problems if the unit traded hands later in theused market. It is for the Super Pas Two only.

I was planning to continue with a descriptionof the “sonic quality” of my reference systemat this time, now that the $7500/pair B&W808s and bridged Transcendence 400 SeriesTwo amplifier are in use, but ran into a prob-lem – the vocabulary used to subjectively de-scribe the sound of an audio system is inad-equate, confusing, and not clearly defined orunderstood. In addition, the terms are nebu-lous, many times describing overlapping char-acteristics rather than specific qualities (de-scribing effects rather than causes). Lets see ifwe can help the matter out a bit by describinga set of terms we shall use from now on insubjective reporting, how these terms relate toother less precise “golden ear” vocabularies,and even hopefully, resolve some of the con-tradictions between what some people like, butothers do not.

In listening to “the sound of music” in an audiosystem, we are listening to the characteristicsof:

Range, Balance, Dynamic Range, TransientCharacter, Musical Character, HarmonicBalance, Definition, Imaging Character, andVowel Tone Colorations.

Each of these characteristics, I observe, canexist for better or worse, nearly independentlyof each other in a given audio system. Theemphasis the listener puts on each characteris-tic, will determine whether he likes the systemor not. Another listener with a different set ofpriorities may reach an opposite conclusionabout the system. Designers of esoteric equip-ment themselves have differing value judge-ments as to which characteristics are mostimportant, execute different aspects more, orless, successfully, and in general appeal todifferent little groups of audiophiles. It is notuncommon for a designer to get one character-istic right and like that characteristic so muchthat he misses completely the fact the equip-ment is below par in other important aspects,put the equipment on the market, and thenwonders why nobody else likes it.

Lets try to define the characteristics and thenlook at how they interrelate.

Range is the easiest to talk about. This issimply how great a frequency response the unitplays reasonably uniformly. A telephone is anarrow range device, a B&W 808 is a widerange device. Note that the Range is not themeasured or “spec sheet” characteristic, butthe real world perceived characteristic. Thereare many components with wide range specifi-cations that don’t play bass (or highs) at all. Ingeneral, consumer grade receivers and “storebrand” speakers have wide range specifica-tions, but real world narrow range (and lousy)performance. From an engineering sense, be-

cause it is more important at how the range isachieved than what the limits of the rangeactually are, it is quite possible to have anarrow range device (carefully executed) soundwider range than a specified wider range unitpoorly executed. Great perceived wide rangeis very expensive to execute properly. Great“spec sheet” wide range is not. In general,pushing the boundaries of the envelope – de-signing to drive the circuits and their parts totheir limits to get wider range yields poorresults. For rational undistorted performance,the device or circuit must always be operatedway inside its design limits. Wider range shouldbe the last characteristic you worry about intrying to improve your audio system.

Balance is the large signal characteristic tell-ing you if the system is “weighted” towardsone end of the Range or the other (or both).Ideally (and reasonably easy and inexpensiveto achieve) the Balance should be neutral. Thischaracteristic is most easily observed in loud-speakers. Many small speakers are so lackingin bass and mid-bass range that they have a“thin” balance. Many “rock” speakers havebooming bass and piercing highs with a Bal-ance most politely called a mid-range suck out.A “heavy” balance obviously is a system withtoo much bass in relation to the rest of therange.

Harmonic Balance is the small signal charac-teristic that if very poorly done, will yieldVowel Tone Colorations. The harmonic bal-ance describes the unit’s ability to play all ofthe overtones of a musical instrument in theirproper relationship. It is the subjective de-scription of a combination of the unit’s fre-quency response smoothness and its freedomfrom spurious resonances and oscillations (bothmechanical and electrical). In a unit with poorHarmonic Balance, the overtone “signature”of a given instrument will be reproduced un-evenly, translating the sound of the instrumentinto “something else.” Flutes change into po-tato whistles, violins turn to plastic, drums tocardboard boxes, for example. Good HarmonicBalance is very difficult to achieve, but notnecessarily expensive to achieve. It requiresthat the designer looks beyond simple IHFmeasurements. Loudspeaker designers mustbuild non-resonant cabinets. Electronics de-signers must keep track of de-stabilizing oscil-lation mechanisms and design them out. Fre-quency response extending schemes such asfeed-forward compensation and under-dampedbass “boosters” cannot be used. These tricksincrease resonances and degrade the HarmonicBalance.

Vowel Tone Colorations are the result of verypoor Harmonic Balance characteristics. Thesecolorations are constant and obvious sonicaspects of the system most easily described asthe sound of speaking a “vowel tone.” Try

saying “Aaaaah,” “Eeeee,” or “Uuuuh.” If yoursystem is always playing one, or more, of thesevowel sounds along with the music, it indicatesthere are internal resonances so severe they aredominating the character of the system. Mostlikely, your loudspeakers are the culprit.Strangely enough, I have heard highly re-garded loudspeakers, raved about in the under-ground press for excellent resolution and im-aging, that have terrible vowel Tone Colora-tions. The Spica TC-50 comes to mind as asystem with an obvious “Aaaaah” soundingcoloration. These colorations are high on mypersonal “pet peeve” list – I cannot toleratethem at all.

Imaging Character is the ability of the sys-tem to recreate the dimension and space of theoriginal performance. It has two aspects. Thefirst is the ability of the system to define eachperformer and instrument as a solid, threedimensional object in space. The second as-pect is to integrate all of the performers into alarger stage duplicating the surroundings ofthe performance. I never judge the accuracy ofthe second aspect unless I was at the recordingsession or have a photograph showing theorientation of the performers and the recordingmicrophones in relation to them, and to thehall. If one does not know what the questionwas, one has no way of knowing if the system’soverall imaging on a given performance is the“right answer.” Some people think the imag-ing can only be “right” if the performance isplaced in front of the speakers. I suggest thiswould be true only if in the original recordingsession, the microphones were placed behindthe performers. Since imaging is the “where isit” aspect of hearing, as contrasted to the “whatis it” aspect, identical channel characteristicswith respect to both frequency and phase re-sponse are the most important concern. If youwant excellent imaging, buy tightly matchedloudspeakers and audio electronics with care-fully matched channels and smooth, criticallydamped roll off characteristics.

To be continued next month, and then an inte-gration of these characteristics to more use-fully describe the sound of audio components.

Frank Van Alstine

VOLUME FIVE NUMBER THREEMARCH, 1986

Oh boy are we busy! Everybody seems toreally like our new product line and orders arecoming in at a rate of about double (at least) asin the past. One client told me, “Frank, youreally have invented a better mouse trap!”Needless to say, we are doing everything wecan to keep up, working nights, training moretechnicians, and going slightly dingy too, butour lead time to fill your order has gone out toa solid 30 days at this time. We don’t want to

Audio Basics Complete 1986 Back Issue Set Page 7

resort to “assembly line” methods. We stillassign each piece to a trained technician tocomplete as an entity. Dave and I still do all ofthe final inspection, testing, and burn in oneach unit. Our methods take time. Please bepatient with us and give us the time to producea custom built quality piece for you. There isnot much in the way of anything in the worldyou can buy any more that exhibits individualcraftsmanship in its production. We don’t wantto be like the rest of the world. We still thinkthere is a place for quality craftsmanship andindividual attention to your needs at a rationalprice. Every phone call to us asking, “Is it doneyet?” simply adds to the time it takes to finisheverybody’s equipment. Help us to completeall orders as quickly as possible with no let-down in workmanship or testing. Don’t call usabout your order unless you really need help.We don’t lose orders. We will notify you ifthere is a problem, and no, we cannot have itready two weeks early, not without breakingpromises to somebody else. We cannot be inthe “instant gratification” business and main-tain the level of individual craftsmanship thathelps make our products such a unique value.Give us the time to do it right.

Meanwhile, Dave, Aado, and I have finishedthe engineering of another new product, theTRANSCENDENCE 100 AMPLIFIER. Thisis our new Series Two Transcendence supercircuits installed in the Hafler DH-120 ampli-fier chassis. This little amplifier (70 watts/channel at less than 0.1% THD open loop)sounds just like our big Transcendence SeriesTwo amplifiers, with the same advantages ofnearly zero noise and simply awesome dynam-ics and transparency. Its 70 watts per channelis a ridiculous understatement of its real worlddynamics into a loudspeaker – it will simplydrive a conventional 200 watt per channelamplifier into the ground.

The object of the Transcendence 100 amplifieris to provide you with Transcendence musicalquality at a more affordable price if the rest ofyour system is of high enough resolution andyour loudspeakers are efficient enough so thatabsolute refinement in the amplifier is moreimportant than outright power and current drive.The price of the Transcendence 100 amplifier,$795.00 outright or $595.00 to install in yourDH-120 chassis, competes with our best sell-ing amplifier, our 140 watt per channel MOS-FET 200C. Which amplifier is for you?

Essentially, if you own loudspeakers that sim-ply require brute power to “turn on,” such asDahlquists, Magnaplanars, Acoustats, big In-finities, Ohms, Apogees, and the like, or if youwant to get the utmost in sheer sound pressurelevels from speakers such as B&W 801s and808s at a reasonable price, the MOS-FET 200Cis your choice. It is, after all simply cleanerthan other amplifiers in this price range and has

great gobs of reliable, durable, and time testedreal power.

If, however, your speakers are a bit moreefficient (or are limited as to how much powerthey can handle) and overkill power is not asimportant as the utmost in refinement andresolution, then choose our new Transcen-dence 100 amplifier.

I have some good news for owners of DynacoPAT-4 preamps and Dynaco SCA-50 inte-grated amplifiers. In our rebuild process ofthese units (to our Super Fet Series Two preampand Mos Fet Control Amp respectively) wehave been able to provide some very usefuladditional switching functions at no increasein price.

For the PAT-4 rebuild, if, and only if, you payfor the optional ($40.00) new selector switch,we will at no additional charge provide yourunit with two sets of tape inputs, two sets oftape outputs, tape to tape monitoring capabil-ity, and an additional set of line level inputstoo.

We can do this by using the Loudnessswitch (previously unused anddisconnected in our Super Fet circuit) as aTape 1 - Tape 2 switch. We then wire theobsolete Tape Head jacks as a second (andindependent) set of tape inputs. The TapeAmp inputs are the first set of tape inputjacks.

The To Tape output jacks become the firstset of Tape outputs, and we then wire theOutput - 1 jacks as the second set of TapeOutput jacks. The Output - 2 jacks becomeyour main audio output jacks to drive youramplifier.

In addition, the Special inputs becomeavailable as another set of line level inputsfor a source such as Stereo TV while theSpare inputs are for your CD player.

Now the Super Fet PAT-4 canaccommodate two tape recorders - eitheraudio or VCR, a turntable, a CD player, aStereo TV, and a FM Tuner and can tapefrom any source to either tape deck andmonitor what you are taping. We really aretrying to build you better (and more useful)products.

For the SCA-50 rebuild, at no additional charge,we are making a simple modification to theselector switch and our wiring to provide simi-lar functions.

The unused Loudness push-button isrewired as a Tape 1 - Tape 2 switch and theTape 2 position on the selector switch isungrounded to provide full tape to tapemonitoring functions “left out” by Dynaco.

Now the SCA-50 based Mos Fet ControlAmplifier can provide tape to tape dubbing

and monitoring functions too, at no increasein price.

Sorry folks, we do not plan on offering thesefunctions as a retrofit all by themselves. Toaccess the switching wiring to make the neces-sary (and rather complex) wiring changes, thepreamplifier PC cards must first be removed.

While this presents us with no additional workwhen starting with a stock unit, or when retro-fitting the new Series Two circuits (in eithercase you are already paying for the changeoverto Series Two circuits and the removal of thePC cards as necessary), the labor time (at$38.00 per hour) to do the tape monitor switchrewiring independently of our normal rebuildprocess will make the cost of the functionssimply too high to be worth the effort. I cannotcontemplate this as a “do-it-yourself” projecteither, inasmuch as we don’t feel very com-fortable about telling you to remove the PCcards from our products!

Thus, we feel it is only economically feasibleto provide you with these new functions as apart of a complete rebuild or when the SeriesTwo circuit upgrade is done.

Note that you must order the optional newselector switch if you want these functionsprovided for a PAT-4 chassis. The originalselector switch simply cannot accommodatethese more complex switching functions. Youmay order the optional switch, and have thetape to tape monitoring functions provided byadding the cost of the switch to the price of theSeries Two upgrade, but only at the time theupgrade is done. Note that tape to tape moni-toring and dubbing functions are standardequipment on all PAT-5 chassis and Hafler101 chassis equipment.

We have done something completely new aboutanother audio problem child, the “BridgedMono” amplifier. Lets talk about the problemsand advantages of this mode of operation for abit, and then see if our solution may be of valueto you.

Bridging an amplifier is a method of tying thetwo separate channels together to make theunit, in effect, into a much higher poweredmono amplifier. Obviously then, you wouldneed two stereo amplifiers, each “bridgedmono,” to provide two high powered channelsfor your stereo system.

Because of the little known laws of Electron-ics, combining the channels of an amplifier bybridging provides more power than you wouldexpect.

Let us, for example, assume that we arestarting with an honest 50 watt per channelinto eight ohms stereo amplifier. Thisamplifier will have the capability to swingabout 28 + and - volts (peak) into 8 ohms.Note that RMS power = RMS voltage

Audio Basics Complete 1986 Back Issue Set Page 8

squared divided by the load resistance(nominal 8 ohms). Note also that oneconverts peak voltage to RMS voltage bymultiplying the peak voltage reading by0.707.

Now, while you might assume that whenyou add together the two channels of a 50watt amplifier, that you would end up witha 100 watt (50 watt plus 50 watt) monoamplifier, this assumption is not correctbecause the “squared” factor wasoverlooked.

Essentially, when you bridge an amplifier,you are not adding together the separatepower ratings of the two channels. Whatyou are really doing is adding together thepeak voltage swing capabilities of the twochannels (with some reservations to bediscussed later herein).

Thus, in theory, when properly “bridged”our 50 watt per channel amplifiermentioned above, will (if it had a nearlyperfect power supply) now swing 28 voltsplus 28 volts, or over 56 volts peak into 8ohms. Now, lets convert this peak voltageswing into RMS power:

57 x 0.707 = 40 RMS volts. 40 squared =1600. 1600 divided by 8 ohms = (surprise!)200 watts! – not 100 watts. Thus, whenyou bridge an amplifier, you in theoryquadruple the power! This is because youare dealing with a voltage squared function,not a simple addition function.

This little “squared function” allows an audiodesigner to slip some really sneaky (but some-times really useful) “spec ratings” into hisdesign.

Lets look at the “good things” about using thislittle known law of physics first:

In a bridged amplifier, each “half” is stillonly operating at the original designvoltage. Our 50 watt per channel stereoamplifier still is working within 30 peakvolts per channel, not the nearly 60 peakvolts of its combined output.

The cost of high voltage parts is muchhigher (all other things being equal) thanthe cost of parts designed to operate withinlower voltage ratings. Actually, when onestarts looking for output transistors, powersupply capacitors, and fast small signaldevices with ratings of more than 100volts (remember, for our 200 watt amplifierwe must allow for a + and - 60 volt peakswing, together with an adequate safetymargin for abuse conditions – 150 voltdevices required) one will find that thesupply of available parts is limited, veryexpensive, and possibly not made at all!

Since high voltage parts and power suppliescan easily be more than twice as expensive,twice as bulky, and twice as difficult todesign and produce with, it often can beless expensive to produce an amplifierwith four small audio channels, internallybridged to make two high powered audiochannels than it is to produce two higherpowered, higher voltage channels.

It is relatively easy to provide a simple“bridge” switch on an average audioamplifier so that you can later economicallyupgrade your system to much higher powersimply by buying an additional matchingamplifier and bridging both of them.

In some applications, such as in anautomobile where one is faced with eithera maximum 12 volt supply or an expensiveswitching power supply circuit to step upthe battery voltage, “bridging” may be theonly easy way to upgrade the 6 wattsmaximum power available from a 12 voltDC supply to in excess of 20 watts.

Finally, in theory, bridging can reducesome forms of distortion. For example,since in the bridged mode, the phase of onechannel is inverted in relation to the other,any “common mode” noise can be canceledbecause the noise (primarily hum) signalswill now be out of phase with each otherand sum to zero.

That’s the good news folks, now for the badnews – all things are not equal when you bridgean amplifier – several bad things happen:

The total current demanded from theamplifier’s power supply is doubled in thebridge mode. In general, any given stereopower amplifier has a power supplydesigned to make its rated power(hopefully) in stereo. A power supply withtwice the current capacity would make thestereo amplifier much bulkier, heavier,and more expensive, and serve no usefulpurpose in the stereo mode. Thus, it ishighly unlikely that the power supply inany ordinary amplifier will be adequatefor actually supplying the doubled currentdemands of four times the rated power.

More likely, the bridged unit will “run outof power supply” somewhere between 2.5and 3.5 times its rated stereo power(depending upon the amount of overkillcapacity designed into the original powersupply).

Referring back to the “sneaky spec ratings”approach mentioned on page 3, it is possiblefor a designer to ignore the “real world”power supply demands, and simplycalculate that his bridged mono amp willgive four times its rated stereo power, andprovide you with a “spec sheet” only power

rating that falls apart under the demands ofreal world current.

Another “red flag” warning! Note that thecurrents through each internal channel ofyour bridged mono amplifier double too!While having overkill capacity in the powersupply is unlikely, having a current reservemargin in excess of a factor of two in eachaudio output channel is almost unheard of!In most cases trying to make your amplifierdrive at twice its output current design willsimply fry fuses or activate protect circuits(if you are lucky) or cook output circuitsand drive boards (if you are not).

Certainly you would be pushing your luck,and the limits of your amplifier, to use aconventional bridged amplifier into a lowimpedance loudspeaker. If, for example,your loudspeakers have a four ohm rating,they require double the normal currentfrom your amplifier already. Since bridgingdoubles the current demands again, fourtimes the current is sure to cause trouble.

Thus, looking back at that “inexpensive”design using four small channels bridgedto make a high powered stereo amplifier,the real answer is, not necessarily a goodidea after all. The designer still must makefour “small channels” with twice thecurrent capability as normal, and still mustinclude a power supply with twice thecurrent capacity too. This will increase theprice substantially – probably right up tothe cost of two high powered, high currentchannels in the first place. Be very carefulin evaluating this kind of bridged design –if its power rating seems to be too good tobe true for the money, it probably is.

One further disadvantage of the “four smallchannels bridged to make two highpowered channels design” – there is no“common ground” available, thus makingit difficult (likely impossible) to use theamplifier with stereo headphones or aspeaker switching network.

Now, another ugly electronic problem comesto light. In a bridged amplifier, the signal fromone channel is inverted and then added to thesignal to the other channel. Some kind of acircuit is necessary to invert the phase of thesignal in one channel. That circuit cannot beperfect (no electronic circuit is). Thus, in aconventional “bridge” the top half of the signalwaveform is not the same as the bottom half ofthe signal – not a very clever idea!

There are several ways of inverting thephase of one channel. The least expensiveis to diddle around inside the feedbackloop of one channel – it is simple to providea switch that changes the feedback (andinternal operation) of one channel of anamplifier from non-inverting to inverting.

Audio Basics Complete 1986 Back Issue Set Page 9

Thus, all you have to do is throw a switchto convert your amp to “bridged mono,”hook the speakers up from hot to hot, andvoila – more power.

Not such a good idea! You now have twodifferent circuit configurations per channel.The internal bandwidth, phase response,and internal distortions are markedlydifferent between the inverting and non-inverting halves of the amplifier. The tophalf and bottom halves of the music signalno longer are the same. In general, stabilitymargins are reduced too.

The usual result – an amplifier that goeslouder, but with less convincing reality,and usually with scrunched dynamics andbass. Useful for “boombox music” but notfor much else.

The other normal approach to a phaseinverter is an additional circuit ahead ofthe power amplifier itself (either anadditional card inside the chassis, or aseparate phase inverter “black box” in linebetween the preamp and the poweramplifiers).

In this scheme, the output from the preampis tapped and fed into a unity-gain phaseinverter circuit. The direct output of thepreamp goes to one internal channel, theinverted signal to the other channel, thespeakers are connected hot to hot, and theresult is high powered bridged operation.The internal feedback of the amplifier isnot changed, so this eliminates the“difference between the halves” problem,yes?

No! You simply move the problem to thephase inverter circuit. The unity gain phaseinverter circuit itself changes thecharacteristics of the signal. In most cases,the unity gain feedback generated addsgobs of transient distortion, and theamplifier drive capability direct from thepreamp compared to the phase inverter aredifferent. You still have two different signalhalves and the music does not cometogether!

So then, is Bridged Mono operation a lostcause? Not necessarily! We have done some-thing new that absolutely cures the second setof problems (two unequal signal halves andadded transient distortion) and then, bridgedmono amplifiers, rationally used, may be use-ful to make your audio system sound better.

The cure is the Transcendence Bridge – fourseparate Transcendence preamplifier audiocards with special inverting mode feedbackcircuits together with a Transcendence Pre-amp power supply. There are left and rightchannel inputs, and four audio outputs – leftchannel non-inverting, left channel inverting,right channel non-inverting, and right channel

inverting. The price – expensive – $500.00installed in your chassis box (minimum sizewe need is 8" x 10" x 3" high) (remember - wedo not make sheet metal and this is essentiallya custom product).

We resolve the “halves matching” problem ina unique way. The signal from the preamp (anypreamp) goes first to an inverting set of Tran-scendence circuits. These circuits first bufferand isolate the preamp from the amplifier andprovide the preamp with an easy load to drive.The signal is filtered and limited to audiofrequencies thus making life easy for the poweramplifiers downstream. The direct output ofthis first set of inverting Transcendence cardsis the inverted outputs. After the first set ofTranscendence circuits, the signal is also fed toa second pair of inverting Transcendence cir-cuits and inverted again. Thus the output ofthese second cards are non-inverting (havingbeen inverted twice). These second circuits arevery wide band in their internal operation. Allof the frequency limiting is done in the first setof cards. Note also that the output sections ofall four cards use our hybrid LH0002CN linedrivers, which will drive any power amplifier(and long interconnect cables) without stress.Of course, our Transcendence circuits are im-mune from the transient overload effects ofnormal unity gain inverting circuits so no addi-tional distortion is introduced. Phase - gaincharacteristics of the inverting and non-invert-ing outputs are identical over a far wider band-width than required for audio.

The result, finally, a method of operating anamplifier in a bridged mono configuration inwhich the top and bottom halves of the signalare identical! You simply have not heard thisdone before! The sonic improvements, ofcourse, are as striking as going from a toyamplifier to one of ours. With any of our poweramplifiers, the Transcendence Bridge will pro-vide you with essentially triple the normalrated power into 8 ohms and safe operationinto four ohms. It will also provide amazingimaging as the two amplifier channels arecompletely isolated (they are separate amplifi-ers!).

For some applications, the TranscendenceBridge is essential. For example, the B&W 808speakers can actually handle 600 real watts perchannel, and bridged T-400 amplifiers give usa real 600 watts per channel into 8 ohms. Theresults, a further reach into the absolute realityof live music, as the dynamic and transientlimitations of more “mundane” equipment van-ishes. In fact, I can now reproduce live “stage”performances better at home than at the con-cert! My “PA System” is simply much betterthan their PA system. Obviously, the Tran-scendence Bridge can give you more absolutepower than it is possible to build into a stereoamplifier at a rational price.

Another logical use is with a set of our muchsmaller amplifiers. The overall cost of a sec-ond amplifier plus the T-Bridge may be lessthan the cost of a new high powered amplifier.Of course, sometimes it is just plain “fun” tohave great gobs of power on tap – kind of stuffsyou back in the seat when you hit the gas pedal.Note that the T-Bridge cannot be used with analready bridged amplifier, in a common groundwiring or switching system, or with the speakerswitcher in the PAT-5 chassis. It should not beused with marginal amplifiers as more currentand heat is generated. But boy is it fun to use!We will continue with the sounds of qualitynext month now that you know what I amdoing to get the sound.

Frank Van Alstine

VOLUME FIVE NUMBER FOURAPRIL, 1986

Well, we are slowly digging ourselves outfrom under the winter avalanche of orders forour new products and have our lead time backto 3 - 4 weeks again instead of 4+ weeks. AudioBasics has been suffering a bit, simply notenough time to do a really good job so far thisyear. It is another Sunday project again thismonth. We do have a bunch of interestingthings to talk about, so stay with us.

I need your help! We are preparing a new“professional” catalogue with type set pages,and a gorgeous cover photo showing the T-200and an array of our PC cards on a translucentblack background. The package will make amuch better first impression on prospectivenew clients. My catalogue preparation advi-sors tell me that it would be useful for me toinclude a bunch of short quotes from some ofmy clients telling readers “how wonderful weare.” I have received many really nice lettersfrom you in the past (and good feedback aboutour products really helps our morale) but I amnot supposed to reprint these comments with-out your prior permission. Let me know if I canuse your written comments in the catalog.

We have made a running major improvementin the MOS-FET 120C amplifier (as of April25, 1986) with no increase in price (until myaccountant tells me the bad news of how muchmore money we are putting into it). How aboutfifty percent more power and lots more“punch”? We did it with a new power supply.In the past, we have used a regulated powersupply in the 120C simply because the rawsupply operated at +90 volts and there were nosmall sized, high capacitance, 100 volt ratedpower supply capacitors available. An adequateunregulated 90 volt supply simply would notfit in the chassis. Thus we used a small rawsupply, and regulated down to +70 volts for themain supply to stay within the chassis limits.

Audio Basics Complete 1986 Back Issue Set Page 10

We now are receiving a new 100 volt rated PCcard mounted power supply capacitor thatmakes an unregulated 90 volt supply practicalin the Dyna 120 chassis. We designed a newpower supply card for this application, whichis now in production. The new power supplyboard replaces the entire regulated supply(original chassis mount capacitors, originalpower supply card, regulator transistor andheat sink – the whole works). Our audio cir-cuits work just fine on 90 volts instead of 70volts (some decoupling capacitors had to bechanged to a higher voltage rating) and theresult is substantially higher power (60+ wattsper channel instead of 40 watts).

Sorry, we are not planning to offer a retrofit forthe power supply as the cost would be too highfor value received (about $150.00). We wouldhave to make changes on each audio card, theoutput ground planes, the output decouplingcard, and redo the entire power supply andrewire the whole thing. The labor time wouldbe extensive for the power and performancegain. The original 120C is a great amplifier.But when we can improve the value you get inone of our products in a real way, we like to beable to do it, especially if we do not have tocharge you extra for the enhancements.

We had an interesting comparison session witha Bedini 25 - 25 amplifier recently. This is oneof the little expensive “cult” amplifier that issupposed to be “just wonderful.” On our testbench it was not very wonderful. It didn’t likecapacitive loads at all. A one microfarad ca-pacitor across our 8 ohm load bank caused theamplifier to generate gobs of ringing in boththe channel the capacitive load was drivingand in the other channel too. This indicates twoserious problems. The first problem, we sus-pect, is an inadequate common power supplycausing lots of crosstalk from the channeldisturbed by the capacitive load into the otherchannel. The second problem likely is feed-back loop failure causing the oscillations toreflect back to the input, thus appearing in theinput to the other channel through our signalgenerator. Neither characteristic is somethingthat makes an amplifier “just wonderful.”

We took a look inside the Bedini and found thatit was chock full of 2N3055 bipolar outputtransistors (the same 75¢ each devices wethrow away each time we rebuild an old origi-nal Dyna St-120). The cases of the 2N3055transistors in the Bedini were colored red (bywhat appeared to be a wide felt marker). Why,I do not know. The power supply was prettyanemic – less than what we use in our low costintegrated amplifier. Someone had been mess-ing with the unit though – the undersides of theaudio boards were cluttered up with wondercaps dangling in mid-air and the outputs werewired up with something resembling weldingcable. (Lot of good that will do – 2N3055transistors will fry before they will heat up a 24

gauge wire – this “mod” is kind of like puttinga culvert after the output of a soda straw.)

The Bedini did not sound too bad. It waspleasant and smooth with good definition andno obvious colorations. Bass and transientcharacter were pretty stifled, though. Drumtransients turned to cardboard and my woofersplayed mud. Recovery time from obvious over-loads was too slow. It did not like digitaldynamics at all. If your taste is analog chambermusic on little speakers that don’t play bass, atmodest listening levels, the Bedini probablywill work as well as many other good amplifi-ers (certainly it is a large cut more musical thanthe Adcom we discussed a couple of monthsago). But if you want to hear all the music(including transients and dynamics) full rangeon real loudspeakers, you had better look foran amplifier that makes a lot more power intoreal world loads.

The internal “modifications” we saw in theBedini are typical of many amateur “golden-ear” engineering jobs. We have noted a fewcontradictions regarding golden-ear recom-mendations:

1. The “experts” claim you gotta have avacuum tube power amplifier to get gooddynamics and really musical sound. Thesesame experts demand that you use speakerwires heavier than the top support cablesof the Golden Gate Bridge to transfer allthat “good vacuum tube sound”downstream to your speakers.

2. Did you ever contemplate what conductorand how heavy its gauge is inside yourvacuum tube amplifier? Yep, you got it –your signal is not going through weldingcables, not through Monster Cable, noteven through pure gnarled copper crystals.It is going through a vacuum! Do you wantto know how good a conductor a vacuumis? Well, it isn’t! You have to heat thoseelectrons red hot and stuff several hundredvolts behind them to get them to move atall! Interesting. One consolation – at leastthe vacuum inside your power vacuumtubes is oxygen free.

Our suggestions: A. Use vacuum speaker wire.Have your local friendly neon advertising lampbuilder blow you a set of pure everything freetubes to connect from your vacuum tube ampoutputs to your speaker inputs. If vacuumworks so nice in a vacuum tube, just think whatit will do for your speaker wires. B. Rewire theinsides of all your power vacuum tubes withMonster Cable or similar. Look at how tiny allthose wires are inside those tubes. You shouldcarefully fix them.

I recently told you that B&W had started sup-plying the models DM110, 220, and 330 withback panel protection fuses. They have nowstarted shipping the DM100 models with fuses

too (no increase in prices). These improve-ments have caused us one minor problem. Thenew fuseholders interface with the crossoversand have changed the layouts of the crossoversin these models. Thus, the instructions wewere preparing for crossover improvements tothese models now need to be rewritten toinclude both the old and the new crossoverlayout configurations for each model. Thiswill set us back a couple of months before wehave the chance to tear down a set of each kindof speakers and write them all up. Note that thelarger B&W models all have electronic protec-tion circuits (no fuses required) and have allfilm crossover capacitors standard. The mod-els DM1200 and DM1400 have been discon-tinued and will be replaced with new modelsthis summer. They were the oldest (and poor-est performing from a dollar value basis) ofany of the B&W models. I will be going to thebig C.E.S. show in Chicago in early June andwill give you a complete write up of what isnew and interesting in the June issue of AudioBasics.

I have a new “toy” to play with that is reallypretty super – the Sony PCM 501 ES digitalprocessor. This is a stereo analog to digital anddigital to analog converter that allows digitalrecording and playback onto any quality videorecorder. It can be switched from 16 bit to 14bit operation (to match other external devices)and can make direct digital copies from onedigital tape to another. It can also record to twoVCRs at the same time. It has a useful peaksample and hold stereo display with 60 dB ofdynamic range in the display. Finally, it makesoutstanding tape recordings.

Hook up into an audio system is pretty simple.You have a set of audio inputs and a set ofaudio outputs that connects to your preampjust like any tape recorder. In addition, youconnect two more cables – to the video inputand video output of your video tape recorder(either Beta or VHS). The PCM 501 ES con-verts the analog output signal from your audiosystem to a digital signal that is sent on to yourVCR for recording as “numbers.” In the play-back process, the “numbers” from the VCR areconverted back to an analog signal (similar toreading and converting the information on adigital audio disc) and the analog signal is sentto your audio system for playback.

Since the information sent to, stored on, andread back from the tape are digital bits (pulseseither on or off) all tape noise, transport noise,flutter, wow, and distortion are simply ignoredby the processor as they are not “bits.” Thus thesystem records with essentially zero distortionand with no noise or speed variations. Dy-namic range and separation are about 90 dBand frequency response is ruler flat under realuse conditions. It will record the full dynamicrange of the best CDs with no overload orcompression. It is obviously superior to the

Audio Basics Complete 1986 Back Issue Set Page 11

Sony “Hi-Fi” FM video recording systemwhich, although very good, does exhibit“breathing” on translations from very quiet tovery dynamic passages. The Sony digital pro-cessor is simply noiseless under all conditions.

Musically, I simply cannot easily tell any dif-ference at all between the direct playback ofthe digital disc and the recorded copy playingback through the processor on my VCR. Itseems not to make tape copies – it makesclones! I like it.

The unit cost me about $650.00. I am using itwith an el-cheapo ($289.00) Sony 5L2300Beta VCR. Thus, the total cost of my recordingsystem is $939.00 – a whole bunch less than ahigh end audio cassette recorder or a bottomend open reel recorder and a whole bunchbetter than the very best studio analog taperecorders. There are a few “catches.” Sonydoesn’t seem to want to make any of these unitsand they are very hard to locate. I got minefrom Q Audio of Boston after a wait of aboutfour months and I think the prices are highernow due to revaluation of the Yen.

There are a couple of more reservations re-garding the use of the PCM 501 ES unit. First,you must be very careful in setting recordlevels to never exceed the zero dB indications.Unlike an analogue tape recorder, which al-ways has much higher distortion and noise butoverloads somewhat gracefully, a digital pro-cessor goes instantly to 100% distortion when0 dB is exceeded because it runs out of bits –crunch! It is not really a problem because withthe much extended dynamic range and signalto noise of the PCM unit, you simply start outat much lower record levels to insure that younever overload. You will have to change yourrecording techniques though if you are used to“pushing” an analogue tape recorder to get abetter signal to noise ratio. You cannot do thatwith a digital machine.

Second, you have to have something worth-while to record! There is not much point re-cording CDs that you already own – its easierto simply play them. I will be recording manyof my best demo records so that I don’t wearthem out but what I really need is a bunch of“loaner” CDs to record.

If any of you out there have any unique CDmaterial that you think that I, and Audio Basicsreaders should know about, simply send meyour CD for my evaluation and return. I willpay the shipping cost both ways and review theCD herein if it is really good material. I willgive you a two week turnaround on the loanermaterial. Call me first to insure that I do notalready have it. All of the recording companiesI have written to regarding Audio Basics haveignored and never responded to my letters(except Telarc). I have already purchased over100 CDs, but I cannot afford all the good

material out there and I have got to hear it togive you a reliable review.

It has come to my attention that I am getting thenewsletter out so late this month that many ofthe topics I had picked for April are no longerappropriate, such as:

How to make your vacuum tube productssound better by soldering in all the pins tothe vacuum tubes directly to the circuitboards (eliminates all those nasty soundingcontacts).

Then, how to carefully check vacuum tubesfor microphonics with a ball-peen hammer.

Testing woofers and tweeters for possibledefects with a broom handle.

How to “shock” your possibly deadelectronics back to life by sparking a deadshort across the outputs while turning themon and off with the volume control all theway up.

How to lubricate and adjust the heads onyour cassette recorder using only a vise-grip pliers and two cups of 3-in-1 oil.

The proper techniques of gob soldering.Practice first with a lit candle drippingwax onto connections from a distance ofone foot. Then repeat with molten solder.For best results, use Kester Gutter Solder.

How to make bad equipment sound betterusing the “super magic brick” (consistingof two cubic feet of lead). You place thesuper magic brick on top of the equipment,it squashes the equipment flat, and theensuing silence sounds nice.

How to pack equipment for shipment withnon-surprising results. First use a press-to-fit box. Then loosen or remove allhardware. Put in box upside down (ifshipping two units, pack them togetherfaceplate to faceplate too). Do not usereturn address or name, and ship fromyour company (General Motors or similaris best so it will be really easy to identify).The non-surprising result is, of course,damaged or lost equipment. Its really fun!

Now, back to something a bit more serious, acontinuation of our discussion (from Febru-ary) of audio system “sounds.” We previouslydiscussed Range, Balance, Harmonic balance,Vowel tone colorations, and Imaging charac-ter and you should probably re-read the lasttwo pages of the February issue at this timebefore proceeding herein.

Dynamic Range is the ability of the system toplay the entire level of the musical content inthe same loudness ratios as what was recorded.Dynamic range is a large signal character asopposed to Transient Character which describesthe ability of the equipment to play the “at-

tacks” of individual notes within the wholescore with convincing reality. Equipment withexcellent dynamic range must be quiet enoughso that the quietest passages are not obscuredby noise, and must have the stability and driveto play the loudest passages without clipping(gross distorting) or compressing the music.The equipment must separate out the quietparts that are playing at the same time part ofthe music is powerful. Some equipment re-sponds to large scale crescendos by putting outan impressive “whomp” of sound. Impressive,that is, until you realize the music doesn’t go“whomp.” This equipment is simply translat-ing large scale input transients intounderdamped output oscillations. It is “fake”dynamic range because all the music is lostwhen the big “whomps” come along. Gooddynamic range requires stable components andadequate amplifier power for the speakers inuse in your environment at the playback levelsyou like.

Transient Character is a bit tougher and isone of the really important “essences” of play-back that if executed really well, leads to aconvincing sense of reality in our audio repro-duction. It is the capability to play all of theinstantaneous power and clarity of the “attacktransients” of individual notes. Good transientcharacter will tell you what kind of a guitar isbeing played, and with what kinds of stringsand pick. Poor transient clarity makes a systemsound like a wet matchbook cover is beingused as a pick, and that the system is always“stubbing its toes” as it stumbles along. It is thebow first “biting” the string, the drum headhitting the skin (before the drum body re-sponds), the air flow being released by the pipeorgan control valves, and the sound starting inthe singer’s throat before the mouth and throatstructure shapes it. Outstanding transient char-acter seems to require outrageous amounts ofclean amplifier power. With a kilowatt of powerper B&W 808, drum sticks tapped on cymbalsand picked strings become stunningly “you arethere” real – the stage and performance havebeen moved “right here.” With less power, thetransient character is still nice to listen to, butnot as convincingly real. This need for awe-some amounts of energy seems to be indepen-dent of playback level. When you have got it,low level playback still seems real, just furtheraway. Transient character seems to be thecharacteristic most ignored in most reviews.“Detail,” imaging character, definition, andlow colorations get all the words, possiblybecause they are much easier to get right,probably because the reviewers have neverheard a playback system that does approachreality in transient character.

Definition is the ability of the equipment toplay back all of the music. This characteristicis measurable, and is inversely related to theamount of transient distortion the equipmentgenerates. If any internal stage of any part of

Audio Basics Complete 1986 Back Issue Set Page 12

the audio chain is driven to its maximum rateof change, then, while that component is satu-rated, all musical information occurring at thesame time, at any frequency, is erased. Poordefinition relates simply to how much of themusic information riding on the sides of waveforms is being clipped off and erased. It’spretty easy to get perfect definition in audioelectronics – simply never let any internalstage go into saturation or cutoff on any inputsignal of any frequency short of output clip-ping (when you get 100% distortion anyway).It is too bad hardly anybody (except us) does it.If you have perfect definition, the definition of“detail” becomes redundant, because “detail”as usually heard, is not music at all, but excesstransient noise bursts caused by saturation ofcircuits. Most people are impressed short termwith lots of “detail” which I define as a zingybright high end. When you get the circuitworking properly, the “detail” goes away, butnow you can understand all the words.

Musical Character is the aspect of perfor-mance that determines how perfectly the datais played back after you have got everythingelse down pat. You can pass all the music, withexcellent dynamic range, transient character,imaging, harmonic balance, range, and withlow colorations and still not present a convinc-ing representation of reality. It simply is asubjective evaluation of how badly you havediddled up the music. It might be compared tohaving all the best possible ingredients for agreat banquet, but the chef had better preparethem perfectly too. Good ingredients not per-fectly mixed and cooked yields a ho-hum (orworse) dinner. Interestingly enough, you canalso have excellent musical character even ifsome of the “ingredients” are missing or are“stale.” For example, a small speaker, in asmall room, with most of the bass range miss-ing can still have excellent and satisfying mu-sical character on most music.

Excellent Musical character is the absence of“sawtooth waves” riding on strings and voices.It is the absence of the “scrunch effect” onmassed strings. It is the system that not onlyplays the notes, but plays the time and spacebetween notes. It is the system that has no“background” for the music but the environ-ment of the recording session itself (and thatenvironment should be obvious). Great musi-cal character requires very low harmonic andIM distortion and absolutely zero transientdistortion at the same time. It requires a com-plete absence of spurious resonances in anypart of the electronic circuits.

Some aspects of Musical Character actually dorespond favorably to “better sounding parts,”if the characteristics of the parts that are im-peding musical character can be defined andimproved upon. For example, electrolytic ca-pacitors have internal resonant frequencies thatare probably too close to the top end of the

audible audio range. These resonances arelikely disturbed by musical transients, causinginteractions and further oscillations within themusic itself. In general, film capacitors reso-nate at much higher frequencies, further fromthe audio range. In case of doubt, an audiocircuit probably is better off if electrolytics arenot used therein. Caution is required in replac-ing capacitors. Many film capacitors have othercharacteristics worse than electrolytics, suchas microphonic and inductive resonances. Trad-ing off one form of interaction for another isnot progress. One must use parts that are realimprovements, not blind steps off another cliff.

Some aspects of Musical Character are frus-tratingly difficult to analyze from an electricalengineering sense. How does one tell, for ex-ample, what is going on between the halves ofa “matched pair” transistor. How much dam-age are the stray electrons bouncing aroundinside a tube doing? There are no models towork with. A perfect circuit cannot be done,because nobody knows where all the problemsare.

Many people honestly believe that “improved”speaker wires and interconnect cables yieldmuch better musical character in their system.I wish I could agree with them as it would be aneasy way out for us, and I would like nothingmore than to be able to recommend the “right”speaker wire and interconnect cable for ourequipment for best musical character. Sorry, Isimply cannot hear it (nor can others, includinggolden-ears I have tested when they did notknow what kind of wires were in the system).

Certainly the various inductive, capacitive,and resistive loads represented by differentkinds of wires can change the sound (espe-cially if the equipment is load sensitive) butchange and better are two different things. Ihear no improvements in musical characterwhen the speaker wires and interconnect cablesare changed.

Now think about how the aspects describedinteract to produce the sound of your audiosystem. See if you can use these terms to betterdefine a system subjectively. We will talkmore about this.

Frank Van Alstine

VOLUME FIVE NUMBER FIVEMAY, 1986

Thanks for all the kind letters of endorsementfrom so many of you. My request of last monthfor quotes for our new (in the preparationprocess) catalog achieved a very pleasant re-sponse from you. I still have room for a fewmore, so if you want to tell others about ourwork, get your opinions in to me soon.

The Sensible Sound has very fair reviews ofseveral of our products in their Spring, 1986issue (number 29). Their address is 403 Dar-win Drive, Snyder, New York 14226 and asubscription (four quarterly issues) is $18.00per year. It is worth the price for the industrynews in the “Ramblings” and “Bits & Pieces”sections alone. They even have a telephonenumber now, (716) 839-4590 you can call totrade information. They do not want “whatshould I buy?” or “what are you going toreview next issue?” kind of calls.

They did answer one question in this issue,namely, “Why do you review Van Alstine’sequipment?” Their answer – because he iswilling to submit equipment for review.

There is one other question that was not asked,that deserves an answer too:

Why don’t reviews of Van Alstine’sequipment ever appear in Stereophile orThe Absolute Sound?

An original Super Pas was sent to Stereophilenearly three years ago. Although it made theirrecommended components list, it was neverreviewed. A Super Pas Two was sent to themlate last summer. It too made their recom-mended list (higher placed) with a note that itwas “shockingly good” and that a full reviewwas coming. It has not come. We wrote to themin November, 1985 offering a Mos-Fet 200Cfor review. The letter has never been answered.

We sent The Absolute Sound a Super Pas in1980. Two years later it was returned withouta mention in the magazine. We sent JohnCooledge (their Atlanta based writer) a Tran-scendence preamplifier and a Super TunerTwo in 1982. They vanished into a black hole.No review, no acknowledgement, no nothing!

Instead of asking The Sensible Sound why theyreview our equipment, why don’t you askStereophile and The Absolute Sound why theydo not? I would sure like to know the answertoo.

We have sent Audio magazine a Transcen-dence 200 Series Two amplifier for review thisspring too. Although we had advertised inAudio for years, they left us off their audiodealer list and their audio manufacturer list intheir last equipment dictionary issue. Theireditor seemed a bit sheepish about this when Ipointed out the contradiction (they happilytook our advertising money but ignored useditorially) and did promise us a review tomake up for the oversight. We were told thatthe T-200 review should show up some timenext winter. Look for it – our hope springseternal.

My request last month for interesting CompactDiscs for review has met with only one re-sponse so far, but with a nice selection of

Audio Basics Complete 1986 Back Issue Set Page 13

material from Mr. Bob Allen of Nevada. Hesent me seven CDs and one Mod Squad Com-pact Disc Damper. Lets evaluate the DiscDamper first.

This gadget is a piece of PC card fiberglass(black) cut the same size as a CD and packed ina CD “jewel box” case. It comes with severaladhesive backed fiber washers that are sup-posed to be glued to each of your CDs to helpcenter the Disc Damper on them.

You are supposed to load this fiberglass boardon top of your CD when you play it, and it issupposed to suppress edge flutter, eliminatelight leakage, reduce digital readout errors,decrease power supply load, and reduce distor-tion caused by focus servo hunting. Interestingclaims for a chunk of fiberglass.

We tried it. We noted the following:

The CD player was much slower in comingup to play speed. The CD player alsodeveloped a small “vibration” kind of likean out of balance tire on your car.

The sound really changed – it wasobviously worse – kind of dry and hardsounding. It made my system sound muchlike a very expensive bright and zippymoving coil cartridge was being used.Yetch!

I am highly suspect of the Disc Damper. Theplatter motor and servos in your CD player areengineered for the mass of a CD only, not fora load more than twice as massive. It appears tome that the extra mass of the Disc Dampercauses tracking errors rather than eliminatingthem. The disc drive servos simply cannotmanage the extra mass. In addition, the DiscDamper was not perfectly balanced and its“out of round” loads increased vibrations andtracking errors.

Certainly disturbing the data flow from the CDwill change the sound of your system as moreerrors are introduced. Certainly this is not away to make your system sound better. We donot recommend the Mod Squad Disc Damper.

I have been doing a bit of engineering on myown Magnavox CD players with good resultsso far. I started the project to trace down anintermittent noisy channel which turned out tobe a defective .0015 µF capacitor in a pre-emphasis circuit. While I had the unit tornapart (its an original FD1000) I also replacedthe original Signetics 5532 op amps with sock-ets and T.I. TL072 fet op-amps. Although theSignetics devices are supposed to be quiet, theresidual noise was cut in half with the T.I.devices. I also replaced the polarized electro-lytic output capacitors with the same 3.3 µFPanasonic film capacitors we use in our Super-Fet Two preamplifiers. The sonic improve-ments were obvious, a smoothing of musical

character and a more liquid and natural sound-ing high end (and it was good, stock). I thenreworked my second unit, a FD2020, with thesame results.

This can be a pretty easy do-it-yourself projectfor those of you with a Magnavox CD playerand some technical skills. You will need toorder the service manual for your machinefrom North American Philips, Technical Pub-lications Department, Box 555, Jefferson City,TN 37760 (they are $15.00 I think) so that youwill know how to get into it safely. You willalso need to acquire two 8-pin dual in-linesockets, two TL072 op amps, and two 3.3 µFfilm capacitors. (We are not stocking theseparts yet.) I also have ordered for each of mymachines, two Panasonic 3300 µF at 25 voltcapacitors to upgrade the power supply a bit.These will directly replace the stock 1500 µFpower supply capacitors. These simple changeswill give you pleasantly purer CD sound. Haveat it!

We are working on a much more sophisticatedMagnavox CD player project right now – acomplete new Transcendence audio output andfilter section to replace all of the originaloutput circuits in any Magnavox machine. Weare running the computer analysis of the filtercircuits right now to be able to set the circuitparameters exactly right. The stock filters area compromise and don’t match each otherexactly under all conditions.

This will be an external package in its ownindependent chassis with a Transcendencepower supply and line - filter circuits. We willcome right out of the A to D converters in the

Magnavox, bypassing all the downstream cir-cuits. With an isolated power supply for theaudio circuits, filters of exactly the right val-ues, and the extraordinary clean current driveof the Transcendence circuits for the filters andinterconnect loads, we anticipate a new stan-dard in CD performance at a rational price. Wewill tell you how well it works (and how muchit is going to cost) next month.

Anyway, back to Mr. Allen’s CDs:

The Nylons, One Size Fits All, (Open AirRecords Div. of Windham Hill OD-0301 DIDX187). Excellent vocal recording of deep anddark male voices reminding me of the InkSpots of years ago. The numbers are mostly1950’s and 1960’s stuff very well done. Excel-lent vocal blending and tonal quality.

The Manhattan Transfer, Vocalese, (Atlantic 781266-2). More modern vocal jazz, again wellrecorded and natural sounding. I like the CDbetter than Manhattan Transfer “Original Mas-ter” vinyl recording I have.

Dire Straits, Brothers in Arms, (Warner Bros.9 25264-2). A good example of bad studiorecording techniques. This modern boring rockalbum is miked too close, with the high fre-quencies first lifted and then chopped. It tellsyou that an all digital production can be poorlyexecuted too. Not my idea of good music,neither in the recording process or in the talentor tunes.

Philip Glass, Glassworks, (CBS MK 37265).A digitally produced modern instrumental re-cording centering around a keyboard and syn-thesizer. I like the recording fidelity and the

Audio Basics Complete 1986 Back Issue Set Page 14

variety of the music – kind of a cross betweenFresh Aire and George Winston.

Michael Hedges, Aerial Boundaries, (WindomHill WD-1032). Excellent and accomplishedacoustical guitar performances of modernthemes. Like many Windom Hill recordings,this floats along free and easy (and that is notbad at all!).

Mark Isham, Vapor Drawings, (Windom HillWD-1027). More modern keyboard with someinstrumental accompaniment. A good bass line.Not as interesting as Glassworks. AlthoughWindom Hill has excellent fidelity, don’t playtoo many of their releases one after another ifyou plan on staying awake.

James Newton, Echo Canyon, (Celestial Har-monies CEL 012). Flute and crickets and moreflute and crickets. The crickets are more inter-esting than the flute. Yawn!

Growing Up in Hollywood Town, (SheffieldLab “Direct from the Masters” CD-13). This isa compressed and limited version of a greatDirect Disc record. The CD sounds like it wasmade from a cassette deck. It is obviously aploy to jump on the CD bandwagon in spite ofhaving nothing much useful to offer the CDcustomer. Try again Sheffield, with a digitalrecorder. If you can do it direct to disc, you cando it on a Sony PCM 501 ES too. A disappoint-ment.

Thank you, Mr. Allen.

One of my readers, Stuart Krivis, of Ohio, hassent me the best “Wonder Cap” I have seen yet.He made it himself out of aluminum foil andthe plastic film from a Wonder Bread wrapper.Actually, it is a Wonder Bread Cap! It has acustom capacitance value – you can change thevalue by squeezing on it. Mr. Krivis tells me itis a “bypass cap” because much to his disap-pointment, so far, everyone has passed it by.Anyway, one loaf of Wonder Bread and oneroll of Reynolds Wrap is probably all you needto Wonderize your whole system. Helpful hint– eat the bread first, peanut butter and jelly donot help the sound of the capacitors too much.

On a more serious note, Mr. Krivis informs methat a simplification of my loudspeaker standbuilding article of several years ago in AudioBasics can be made. He suggests, if you do nothave access to a router, that a water closetfitting can be fitted to the top and bottom of thebase and then the pipe will slip over, and can beglued to these fittings. Check with yourplumber.

O.K., how about a do-it-yourself project now?The crossover upgrade for the B&W DM100loudspeakers. These instructions are for thenon-fused versions only (all production beforeSpring, 1986).

You will need the following parts:

2 7.0 µF 100 volt film capacitors

2 8.0 µF 100 volt film capacitors

2 10.0 µF 100 volt film capacitors

Digi-Key, Box 677, Thief River Falls, MN56701 (1-800-344-4539) has suitablePanasonic E-Series capacitors available. PartNumber E1685 (6.8 µF 100V), Part NumberE1825 (8.2 µF 100V), and Part Number E1106(10 µF 100V). These values are well within thetolerance required. The prices, in single lot, are2.35, 2.86, and 3.23 each respectively. There isa 75¢ service charge on orders this small, plusshipping.

You will also need the following tools andsupplies:

A Phillips screwdriver, a soldering pencil androsin core solder, a wire cutters, a hot glue gunand glue, and a flat bladed screwdriver.

Cautions! Although this project does not re-quire exceptional skill, it is rather easy todamage your speakers with a slipping screw-driver or excess force. B&W will not providewarranty repairs for drivers with holes pokedin them. You must also be able to make goodsolder connections. If in doubt, enjoy the speak-ers as they are.

You may use other brands of film capacitors asyou choose. The capacitance values should bewithin 10% of specified (matched pairs arebest) and the voltage rating must be no lowerthan 100 volts. In general, choose capacitorsthat are non-polar, small, non-microphonic,and non-inductive.

Lets get started.

1. Lay the DM100 on its back on a cleanworkbench and remove the grill. Removethe four Phillips screws securing thewoofer. Gently lift up the woofer andunclip the two leads noting the orientationof the wires (brown goes near the red dot).Write down the location of the red dot asit is possible, but not likely, that it may falloff while you are handling the woofer. Setthe woofer aside (cone up).

2. Note that there are eight screws on the faceof the tweeter. Do not touch the fourinner screws! These hold the magnet onand if you loosen them you will destroythe tweeter. Remove the four outer screwsonly and lift up the tweeter. Note that thered wire goes to the red lug. Unclip thewires and set the tweeter aside (dome up).

3. Note how the dacron fiber is packed in thebox. Remove the fiber and set it aside.

4. Note the orientation of the crossover in thecabinet (red wire at the top). Turn the boxon its side. Carefully push the crossover -speaker terminal plate out the back of the

box. It is a stiff press fit. Set the speakercabinet aside.

5. Compare your crossover with the drawing.It should match the drawing exactly,although some of your parts may bemounted “values down” so that you cannotread the values printed on them.

6. Begin with the 7 µF capacitor. Unsolderone end from the ground solder lug and theother end from the brown wire and chokewire. Pry the capacitor loose with the flatblade screwdriver. Hot melt glue the new7 µF film capacitor in place. Solder onelead to the ground solder lug and the otherlead to the junction of the brown wire andthe choke.

7. Unsolder the leads from the 10 µF and 8 µFcapacitors. Use the screwdriver to removethe 10 µF cap from the top of the 2.2 Ωresistor and to remove the 8 µF cap fromthe terminal plate. Hot glue the new 8 µFcap onto the plate and then hot glue thenew 10 µf cap onto the resistor and the 8 µFcap. Make sure the resistor is secured tothe plate too.

Solder the lead on the outside end of the 10µF cap to the adjacent resistor lead. Solderthe outside lead of the 8 µF cap to the redwire. Connect the leads from the insideends of the 8 and 10 µF caps together andsolder them to the choke lead next to the 8µF capacitor.

This finishes the wiring work. Your crossoverconnections should be exactly as shown in thesketch.

8. Press the crossover plate back into thespeaker box with the red wire up. You mayuse four dots of hot melt glue to secure theassembly in the box (from the inside) butdo not overdo it as you may want to removethe crossover again.

9. Gather the speaker wires to one side andreplace the dacron fiber back in theenclosure. If there was a gasket on thetweeter, fit it back in place.

10. Reinstall the tweeter with the red wire tothe red lug, the black wire to the black lug,and the clips pushed firmly on. Tighten thefour mounting screws firmly but not tootight.

11. Connect the brown wire to the red dot (+)lead of the woofer and the blue wire to the(-) lug. Align the woofer on the enclosureand secure it with the four large screws –not too tight! Replace the grill and you arehalf way done.

12. Now connect both speakers to your system(the stock one and the rebuilt one).Compare them carefully. If there are grossdifferences between the two you may have

Audio Basics Complete 1986 Back Issue Set Page 15

made a mistake. If you are simply gettinga smoother frequency response and betterdefinition from the modified speaker, youare ready to go back and begin on the otherspeaker system.

The finished pair should be obviously superiorin musical quality and be well worth your timein doing this project. Thank you GreggMcArthur, my Chicago area rep, for preparingthe basic instructions for this project. We willmove on to other models in the near future.

Stop the press! A very interesting product justcame in the door while I was writing this.Audioquest, 629 Camino de los Mares, #306,San Clemente, CA 92672 (714) 240-0604 hassent me a couple of sets of their SorbothaneTube Dampers and their Sorbothane Isola-tion Feet. I just took a 15 minute break and canreport to you that these accessories work asadvertised!

The Tube Dampers are very clever. You sim-ply slip one over each signal tube in yourvacuum tube preamplifier (they are not forpower output or rectifier tubes) and they “re-move” a layer of extraneous “haze” that youdidn’t even know was there. We did a quick A- B with a new Super Pas Two and really likethe results. The sorbothane ring around thetubes damps out mechanical vibrations gener-ated by the tubes themselves and makes thepreamp run quieter and clearer. These littleguys will cost you $12.00 for a set of four (allyou need for a Super Pas Two) and we wouldhave to say, based upon our first listen, is thatwe highly recommend that you get them. Weare going to stock them, but for now you canorder them directly from Audioquest. [1990Note: The most recent batch of Tube Damperswe used tended to melt on the tubes in thepreamp - not a pretty sight. I don't know if theyhave changed the mix or if our current 12AX7Atubes run a bit hotter, but we are not using thedampers any more.]

Audioquest’s Sorbothane Isolation Feet maywork wonders for you too. They are about thesize of hockey pucks and, like a meat ball,won’t bounce! A set under the Super Pas Twohelped it some more (not as dramatically as theTube Dampers though) and I already haveanother set under this word processor whichgives the keyboard a nicer feel and makes theprinter much quieter. In my system, with myturntable mounted on 1000 pounds of concreteand sand, they made no change there, but theymay help isolate many of your components(CD Players, Turntables, Power Amplifiers,and even your TV set). They are a bit moreexpensive, $10.00 each, and I doubt if I willstock them for now. But they probably havemany more useful applications.

Audioquest also makes the sorbothane mate-rial in 6" x 6" x 1/10" self sticking sheets. You

can cut and place this material in a variety ofplaces where it is desirable to absorb and dampout unwanted mechanical energy, both in au-dio systems and in other every day applica-tions. The sheets cost $15.00 each. Order thesedirectly from Audioquest and let me knowwhat useful applications you find for the mate-rial and I will report your findings here. Got togo now, next month the C.E.S. show report.

Frank Van Alstine

VOLUME FIVE NUMBER SIXJUNE, 1986

Due to business and other commitments, I willbe out more often than in during the nextmonth. Dave and Aado will be here running thebusiness with the same care and capability Iput into it. Remember, Aado designs most ofthe equipment and Dave is my manager whoinsures that each order is properly filled, andthat each unit is properly built and tested. Theyknow as much as I do about the equipment,maybe even more. Thus, when you call usduring the next few weeks, don’t ask for meonly and waste your time and ours. Let Daveor Aado help you; they can help you as well asI can. We operate as a team, not as a “onepersonality” organization. Take advantage ofour capabilities. I must have the time to visitfactories, evaluate new products, and deal withsuppliers. I cannot be here to answer the phoneall the time. If you only are willing to talk to (orplace an order with) me, then you keep ourteam from serving you best, and interfere withour abilities to serve you best in the future.Thank you!

I had an interesting customer complaint lastmonth. The fellow listened to, and purchased,a Super Fet preamp and Mos-Fet 150C ampfrom us. A week later he called to lament abouthard, glassy, grainy, and two dimensional soundwith the equipment in his home system. Inas-much as this is a very unusual response to ourequipment, I dug deeper with him to find outwhat else was being used with our equipment.

I found out that since he had really been im-pressed with the CD performance of our demosystem, he had gone right out to a high endsalon and purchased a CD player. And, sincewe got such musical performance with a$149.00 Magnavox CD player, just think howmuch better his system would sound if hepurchased a really good (and expensive) CDplayer. Besides, the salesman at the salon toldhim that the Magnavox units were not anygood. Thus, he was the proud owner of a new$600 Yamaha CD player.

I asked him to bring it out for evaluation in ourreference system. He did. With the Yamaha, Itoo had the same hard, glassy, grainy, and twodimensional sound he had described. The

Yamaha CD player was simply awful! Wetook it apart and found it was built even cheaperthan the lowest priced Magnavox units, withnowhere near the engineering excellence ofthe Magnavox. We patched the Magnavoxback in and all was well again musically. Thereare differences between CD player brands. Ina nutshell, nearly all Japanese units I haveheard sound like Japanese mid-fi receivers!This should not come as a surprise to you; afterall, their audio stages are right out of theirreceivers.

I have now had “hands on” experience with thenewest (lightweight) Magnavox 2041 and 1041units. I have good news – they perform just asnicely as the older massive Magnavox units.Although they are nearly all plastic, there havebeen many very clever engineering improve-ments. The disc drive mechanism is probablybetter shock isolated than the older units. Themuch simpler looking PC card is actually muchmore sophisticated. It is a shielded card withhundreds of chip devices mounted directly tothe foil paths on the under side of the board.North American Philips has actually put all thenecessary circuits on one simple board in lessspace, and at less cost, than in their old twoboard shielded cage installation. The price forthese units is $200 or less. I highly recommendthem.

Aado, Gregg McArthur, and I spent the firstweekend in June at the giant Consumer Elec-tronics Show in Chicago. This is the annualhome electronics trade show at which nearlyevery supplier of home entertainment productsdisplays their wares to possible buyers. We getto see and hear nearly everything there is all atonce – it’s kind of overwhelming!

McCormick Place, the giant three level expo-sition hall (you could play about ten footballgames at the same time inside) on Chicago’sLake Shore was stuffed with every car radio,satellite receiver, TV set, VCR, and boom boxever made. The nearby McCormick Inn had allits meeting halls and three floors of hotelrooms full of mainstream audio equipmentdisplays. Downtown, there were two hotelsfull of “esoteric” audio products, and anotherfootball field sized exposition annex held acresof porno film purveyors and home computerremnants. There were many other “privateshowings” of equipment scattered throughoutother Chicago downtown and airport area ho-tels. No single human could possibly see it allin the four days the show ran. We concentratedon those products of interest to you.

I guess my first general overall observationregarding audio equipment is that there is anever widening chasm between the mainstream“mid-fi” equipment and the esoteric “hi-fi”equipment, in performance, price, and avail-ability, that in general serves the lover of musicvery poorly!

Audio Basics Complete 1986 Back Issue Set Page 16

The “marketing” of mass produced audioequipment is rapidly being dominated bythe “Super Stores” who care not whatanything sounds like but are only inbusiness to “move” boxcars full ofmerchandise at supposedly discount prices.

These Super Stores are driving theindependent home entertainment storesout of business.

Thus the suppliers to the smaller stores,the NADs, the ADCOMS, the CARVERS,the INFINITIES, the B&OS, (and similar)are seeing their retail base being seriouslyeroded out from under them.

This forces these producers of rationalequipment into a box from which there areno really good choices for you, the personwho appreciates music more than blinkinglights and fads.

The good quality audio supplier can goahead and sell to the discount super stores,but there is a catch. Since there are notrained audio salesmen or rational listeningfacilities in these “electronics barns,” thepotential customer will have no expertguidance to help him separate the qualityfrom the plastic. In general, the buyingchoice will be based upon price andfeatures. Good equipment simply does notsell to the uninformed buyer if his choiceis “flashier” equipment with more featuresat a lower price! Thus, the producer will beforced to build “Super Store type”equipment – cheap circuits, lots of buttonsand lights, and worse sound. You lose!

The caring supplier’s other choice is tocontinue to supply good quality equipmentto independents, watch them go out ofbusiness due to overwhelming pricing andadvertising pressure from the Super Stores,and then go out of business themselvesbecause of a lack of markets. You loseagain!

It will be interesting to observe the nextfew years and see if the best of the qualitysuppliers and their dealers can effectivelydeal with this threat. Meanwhile, ourposition as a direct mail supplier of highquality equipment to informed and caringmusic lovers does not seem to be too bada place to be.

Anyway, lets talk about some of our mainsuppliers first.

Hafler showed nothing new, except samplesof their $400 car amplifier (to be available“this fall”). All of the products we build intoHafler chassis, and stock Hafler componentsthemselves, will continue as you know them.When we get the car amplifier, we will installit (along with B&W MASS speakers) in myAudi Quattro and report on the performance,

both before and after we engineer Transcen-dence audio circuits for the car amplifier.

Harman-Kardon , unfortunately, is discon-tinuing nearly all of its turntable models, in-cluding the T-30. They have about a threemonth’s supply of inventory left, but after that,they will be all gone, unless they can find a newsupplier to make them. Their previous turn-table supplier (who built the units under con-tract to H-K) is getting out of the turntablebusiness completely – the CD strikes again!We have inventory and can supply you withour T-30 special units for now, but not longterm. If you want to get that one last qualityrecord playback system before there is simplynothing left to play your records with, actsoon!

Grado, as usual, was not at the show. Theyspend not a penny on advertising or promotion,and simply build better cartridges for the moneyas there are no advertising costs built into theprice of their products. The Longhorn Gradowill continue to be available.

We looked very carefully at the new top of theline Dual turntable. It has some promise, in-cluding a 78 rpm speed for you antique recordcollectors. I have asked the Dual factory repre-sentative to get me a sample. I hope that manyof the engineering improvements we made tothe T-30 will also work on the Dual. If so, wewill let you know. It will be more expensive.

B & W Loudspeakers had an outstandingdisplay of three brand new loudspeakers at aprivate showing at the University Club in down-town Chicago. The new loudspeakers are theMATRIX 1 , the MATRIX 2 , and the MA-TRIX 3 .

These three new speakers share the followingrather revolutionary new technology:

Their cabinets are filled with a complexseries of interlocking cross bracing panelslooking much like an egg crate. Thesepanels lock into, and are bonded to, thetop, bottom, front, rear, and sides of thecabinet. The spaces in the matrix ofinternal bracing are then completely filledwith bars of acoustical foam. The highlysuccessful results of this constructioninnovation is to provide a loudspeakercabinet that is absolutely inert. Actually,the cabinets are stiffer than if made ofconcrete, and are much more inert than thevery expensive Celestion Aerolam metalcabinets (which “ring” at high frequencies).Acoustic output from the cabinet structureis simply eliminated.

The drivers used in the Matrix speakersare all new too. The cast frame becomesthe whole face of the speaker, rather thanbeing bolted to the box. All the channels inthe frames are filled with damping

compound! They have put into productionthe very same damping techniques Ishowed them when I visited their factoryin 1981 and which I have been telling youabout for years! The Matrix series arereally a partially Van Alstine designedsystem!

Cone materials are new. Although B&W’sKevlar cones are optimum, the productionyield is low and thus the cost is very high.B&W needed an equivalent performingmaterial that could give you a better price- performance ratio than Kevlar.

They have produced a nearly ideal conematerial, a homopolymer polypropylenewith much better internal damping andstiffness than the more usual copolymerpolypropylene used by other speakermanufacturers. Because the homopolymermaterial is unsuitable for packagingmaterials (the most widespread applicationfor copolymer polypropylene) it is rarelyavailable. Thus, B&W had to contractdirectly with a plastics manufacturer inEngland to produce the new cone materialfor them.

The new polyamide dome tweeters areferrofluid filled, have all mounting platecavities filled with polyurethane elastomer,and are built into castings that are anintegral part of the cabinet face. The stepfunction linearity of these new tweetershave been improved from 6 volts to 14volts, substantially improving dynamicrange of the systems.

The crossovers, although complex (andcontaining electronic protection circuits),are simplified from some previous modelsbecause the out of band roll-offcharacteristics of the Matrix drivers moreclosely approach an ideal 12 dB per octave.They are built with all film capacitors(except for the large DC blockingcapacitors to the woofers).

Even the stands are improved. There aremassive marble base stands available forthe Matrix 1 and Matrix 2 with filled anddamped steel vertical supports. These arestrongly recommended for optimumperformance of the speakers.

The Matrix 1 is 9" wide, 16" high, and 12 5/8"deep. It is a two way system weighing 22pounds with a 150 mm woofer. Its sensitivityis 85 dB and its maximum clean output is about106 dB. It is a 4.5 Ω system recommended for50 to 120 watt amplifiers (at 4 Ω – any of oursmaller amplifiers). Its list price is $499 eachplus $199/pair for the stands.

The Matrix 2 is 10 1/4" wide, 23 1/2" high, and12 1/2" deep. It is a two way system weighing35.2 pounds with a 200 mm woofer and a moremassive magnet structure. Its sensitivity is 87

Audio Basics Complete 1986 Back Issue Set Page 17

dB and its maximum clean output is about 110dB. It too is a 4.5 Ω system and is recom-mended for amplifiers between 50 and 150watts. Its list price is $699 each plus $229/pair for stands.

The Matrix 3 is 10 1/4" wide, 35 3/4" high, and16" deep. It is a three way floor standingsystem with two (more massive yet) 200 mmwoofers. Its sensitivity is 90 dB with maxi-mum clean output of nearly 120 dB! It is a 4.5Ω system for amplifiers of 50 to 200 watts (anyof ours). Its list price is $999 each (stands notrequired).

Obviously, after we have completed an “inhouse” evaluation of these products (samplesare now on order) we will set our own lowerprices. Call us for details.

Now for the obvious question, “How do theysound?” In a word, superb!

Given the constraints of a strange roomand different electronics and sourcematerial than I am used to (B&W’s ownbig mos-fet amplifiers and PCM videotaped program material) the quality ofthese new systems was obvious.

My initial impression is that the Matrix 1will outperform the DM2000 in all respects(range, dynamics, and clarity) for a lot lessmoney and in a lot less space. I suspect theMatrix 2 will do the same thing to theDM3000. Finally, the Matrix 3 obsoletesthe 802 and probably will give the 801FSpecial a lot of trouble too. The onlyexpensive previous generation model thatstill emerges as a clear winner is theawesome 808. Note that 2000, 3000, 802,and 801 speakers still remain available.

The clarity, dynamic range, transientcharacter, and overall range of thesespeakers is very surprising! All in thelarge demo room nearly fell off their chairsupon first hearing the Matrix 1 put outdynamic deep and clean bass we normallyexpect from cabinets five times as large. Itseems as if the Matrix cabinet structuregreatly extends clean bass response asmore “flexible” conventional cabinetdesigns simply “eat up” bass energy andturn it into cabinet vibrations and heat.Imaging and staging was lifelike. It seemsas if having all the sound coming from thedrivers, and none from the cabinets, putsall the music where it is supposed to be,without extraneous output from thecabinets and surfaces near the cabinets.When you hear the music, all the music,and only the music, imaging improvementscome automatically without need forelectronic gimmicks.

Obviously, my initial impressions aresubject to conformation with more realistic

tests in my own studio, but, I did get onefurther comparison.

B&W had set up, in an adjoining room,their Active 1 self powered systems, a$3400/pair three way systems similar insize to the Matrix 2. I stuck my head in thedoor to this demo room and gave a quicklisten. After the Matrix demonstration, theActive 1 room sounded like I was walkinginto a mud factory! Enough said.

Only one piece of slightly bad news at B&W.Due to the recent decline in the value of theU.S. dollar in relation to the Pound, there hasbeen small price increases (effective immedi-ately) on the 100 series loudspeakers. We willnow be selling the DM100s for $240/pair, theDM110s for $350/pair, the DM220s for $520/pair, and the DM330s for $675/pair (still undera new higher list price). 100 series stands arenow $60/pair. The recently improved 100 se-ries speakers (all are now fuse protected andhave more “open” grill assemblies) remaingreat values.

Needless to say, the B&W Matrix series waseasily the best example of advanced engineer-ing at the entire C.E.S. and was really the onlyone in which advanced engineering actuallyresulted in major improvements in sonic real-ity.

Of course, B&W was not alone in offeringgood sound, but the examples were, to my ears,few and far between. In almost all “high end”rooms, I could have walked in with a Mos-FetControl Amplifier and a set of B&W DM110sand simply wiped out many thousands ofdollars of overpriced and bizarre equipment.But let’s talk about the nice things I heard first.

Bob Carver showed prototypes of a simplyamazing loudspeaker, called, of course, theCarver Amazing Loudspeaker. It looks some-thing like the dreadful Apogee Scintilla, butsounds markedly “live” and dynamic as com-pared to the compressed and bland Apogees.The Carver speaker looks like a “planar”speaker, but is not. It uses several square woof-ers and something that looks like a ribbontweeter, but isn’t (according to the Carver repI talked to). Details are not yet available. Theyare supposed to sell for about $1500/pair and tobe easy to drive. I suggest you keep checkingwith your nearest Carver dealer and give thesea listen.

DCM had a nice display of the Time Frameloudspeakers. These too are thin (7" deep) andlook like planars, but actually are closed trans-mission line systems. They sounded musicalenough to recommend to you that you listen tothem for yourselves. Their display of the smallermodels sounded much better than the roomdedicated to the largest Time Frame.

Audio Research easily had the best (mostmusically convincing) display at the “highend” hotels, but only with their most expensiveSP-11 hybrid Fet-Tube preamp ($5000!) andtheir most recent version of the D250 vacuumtube amplifiers ($6500!) driving Infinity loud-speakers. It should sound good, for the systemprice, you could afford to buy the orchestra!Their “cheap stuff” ($2000 or so each) drivingDahlquist DQ-20s, sounded grainy and flat –like ho-hum solid state equipment.

Quad displayed their electrostatic speakersalong with all Quad electronics and producedfamiliar Quad (civilized and musical) sound.They haven’t changed anything and probablywon’t for many years. Next door, KEF had amost uncivilized display, bright and brashsounding. It appears as if they are trying toappeal to the upper end of the Super Storeshopper.

Bob Fulton was back, with a display of newloudspeakers featuring “Oval Windows.”“They are not tuned ports!”, says Bob. Sure.They also have “Acoustical Yokes.” In spite ofthe literature (a yoke), they sounded sweet andnatural, as most of Fulton’s products have overthe years. He really gets a lot out of O.E.M.drivers and certainly is more of a musical artistthan a musical engineer and is fun to listen to.

Richard Shahinian displayed his Obeliskloudspeakers very effectively and got musicalsound in hotel room conditions that were be-yond the capabilities of most other companiesto deal with. Again, Shahinian Acoustics prod-ucts are worth evaluating.

Outside of audio, Sony displayed very highresolution digital TV sets and pushed 8 mmVCRs. It is obvious that they are giving up onBeta. Their 8 mm cameras had excellent reso-lution, better than Kodak’s 8mm system un-der similar show conditions.

Sharp showed a 3-D VHD (video disc) Sys-tem. It works just fine, with electronicallycontrolled liquid crystal shutter glasses youneed to wear while watching your TV set.Now, all that is needed is some 3-D moviesmore modern than The House of Wax!

Kloss displayed the highest resolution bigscreen projection TV I have yet seen. If youwant a projection TV, Kloss is the way to go.

The Satellite Receiver business is dying!(Down 90% since scrambling.) There is a bigscam going around you need to be warnedabout. Some unknown outfits are selling “boot-leg” de-scramblers guaranteed to pick up HBOfor high ($700) prices. They work! The catchis that they are simply M/A-COM decoders(available for $395 anywhere) repackaged!The fly by night outfit simply prepays HBO forsix months of service before sending you their“black box.” When the subscription expires, so

Audio Basics Complete 1986 Back Issue Set Page 18

does your de-scrambling ability! There is areal universal de-scrambler available, calledthe Black Box Solution, but it handles videoonly. Audio signals are digitally encrypted andwill be much more difficult to de-code. TheBlack Box Solution is illegal unless you paythe broadcaster for viewing rights.

Getting back to audio, most of the rest of theesoteric equipment simply is not worth talkingabout. It is vastly overpriced and in generaltotally lacking in convincing dynamic charac-ter and musical intensity. Good tonal balanceand resolution alone is not worth thousands ofdollars per product.

One great new product was not at the show,because we just finished it today – THE TRAN-SCENDENCE CD PLAYER! It is $795.00complete. It has profoundly better bass, dy-namic range, musical intensity, and resolu-tion than any other CD player (or any othersource) you have heard. Call us about it andallow 6-8 weeks for delivery. It’s got five ofour new circuit boards inside a Magnavox2041 chassis. You won’t believe it ‘till youhear it. Out of space for now – next issue willbe in early August.

Frank Van Alstine

VOLUME FIVE NUMBER SEVENJULY, 1986

We are late this month because I just got backfrom a trip to Europe with the family. Wepicked up a new VW Quantum Syncro (fourwheel drive) and meandered around the conti-nent for a month visiting Holland, Belgium,France, West Germany, Italy, England, and afew other places. I could write this whole issueabout driving in Europe (takes about 100 timesthe concentration as in the U.S.A.) and whatinteresting things we saw and did, but I won’t.This is supposed to be an audio newsletter, nota travel guide.

I will mention that it is nice that the U.S. newsagencies scared all the panicky tourists awayfrom Europe with vastly over exaggerated re-ports on terrorism. It made it easy for us to findhotels and visit uncrowded areas everywhere.At a reader’s request, I would like to talk a littleabout Audio Test Clinics this month. Theseare those great occasions when some manufac-turer sets up his test equipment at a pet dealerand has you bring in your amplifier to measure(and always, to show you how bad it is com-pared to the manufacturer’s brand).

I have three observations regarding these clin-ics:

1. They make lots of unusual business forrepair shops such as, “My amplifier has aspec. of .01% THD and at the clinic itmeasured .02% THD so it has twice asmuch distortion as normal so you better

fix it!” Sorry, dear panicked customer, theprecision of testing at a typical clinic is farworse than the precision of your amplifier– like trying to read 6 place accuracy on abroken slide rule. These “numbers” aremeaningless unless done in accordancewith repeatable standards – such as havingthe test equipment isolated from theequipment being tested and using aregulated 120 volt bench power supply,for starters, which I have never seen done.

2. It is really easy to “null” the test equipmentso that the distortion in the manufacturer’sequipment is canceled, but at the sametime the reading is much higher than normalfor any other brand of equipment. Afterall, who is running the test?

3. The best “trick” though is to test for somespecial characteristic that only themanufacturer’s equipment has (eventhough that special characteristic isvalueless).

For example, McIntosh is now runningclinics that claim to show that theiramplifiers do not distort when grosslyoverdriven, and that other brands do badlydistort, thus claiming that only McIntoshis “digital ready.” Of course, any amplifierwill exhibit distortion when driven beyondclipping. You can, however, keep theoutput distortion looking low by simplyclipping the input signal first. You willstill get the same amount of distortion (aclipped signal is clipped) but if you measureonly the output, you won’t measure thisdistortion (but you will hear it still!). Sorry,McIntosh, moving your distortion to adifferent place does not remove it, nordoes it make your equipment “digitalready,” it only makes it “advertising clinicready!”

Your audio system can only be as good as yoursource material.

Those many pages of agonizing prose in TheAbsolute Sound and Stereophile purporting toexactly describe all the marvelous nuances anddelights of the supposedly true to life megabuckequipment rest on one assumption – that theplayback source material being used to evalu-ate the equipment is high fidelity. It isn’t! Allthe experts are doing is evaluating how theirbung source material is interacting with theirbung equipment. They are endorsing equip-ment that has no chance at all of reproducingthe dynamics and intensity of live.

Instead of listening to equipment, let’s go to alive concert and spend a bit of time listeningthere to the differences between live and “highfidelity” audio playback. Let’s see if we canverbalize the obvious differences we hear.

Live is smooth! There are no rough edges.Sure, there are “rough and raspy” sounding

instruments, but the sound still is smooth –there is no unnatural harshness – only thepleasing combination of harmonics producedby that instrument. The raucous sound of somereed and antique instruments is pleasing, notfatiguing like the residual harshness of audioplayback systems.

Live is powerful! The softly drawn bow of aviolin in the hands of an artist simply fills thehall in a way no audio playback system can. Ihad the fortunate experience a couple of weeksago to attend an organ and violin concert in agreat 12th century stone cathedral in Germany.There were only two musicians – violinistErno Sebestyen from Munich and OrganistHans Joachim Erhard from Aschaffenburg.The program featured works of Handel, Bach,Holler, Mendelssohn, and Vitali. To be honest,I had expected the violin to be overwhelmed bythe newly built (1967) great pipe organ. I wasa big dummy! It was not – the violin playedwith equal power. That tiny instrument carriedand filled the cathedral with some of the mostlush string sound I have ever heard, matchingperfectly the acoustical output of the hugeorgan. The concert was magnificent! To acertain extent, it sounded like a human being,the violinist, had been captured and made alive part of the great organ – it sounded like theorgan was alive. It was a unique experience(there are not too many 12th century cathedralsin the U.S.A.).

Live is clear! It is the clearness of the violinbow starting to play a note, the organ stopopening and the air beginning to flow justbefore the tone of the pipe is audible. It is theclearness of the singer starting to form theshape of the note before it is really sung. It is allthe little clues we hear live that simply are notthere in recorded playback. Sure the very bestplayback system kind of gives us hints of theseclues, but it is not the same as live.

Live music has an intensity of dynamics, evenin low level passages, that is utterly lacking inaudio playback systems. Listen carefully to theattack of a lightly tapped cymbal, the transientsin a bowed string bass, the quickness of aplucked guitar. It becomes obvious that eventhe finest audio system is simply loping off andscrunching most of the dynamic attacks of live,even at low listening levels.

Live music has duration ! Each note “hangs”for a while in the air. It is not cut off as soon asit is played. Listen again to the tapped cymbal.Listen to how long it plays, and to what acomplex set of harmonics it plays, slowlyfading out. Until very recently, I had neverheard an audio playback system handle theduration of live correctly.

I think you have to agree with me that there stillremain big differences between live and audiosystem playback quality.

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Where are the most serious remaining prob-lems? There are lots of possibilities. Perhaps itis the interconnect cables and speaker wires?Gosh, maybe they do have to be made ofUnobtainium and only under a full moon. Ifthis is the line of research you want to invest in,you had better find another source for advice.This reminds me of an interesting experimentI proposed to a magic wire producer at theC.E.S. Show.

These people were selling speaker wires thesize of fire hoses at solid gold prices. I inves-tigated to find out what could possibly be sovaluable about a chunk of wire. I was informedthat the wire was “tri-axial” in its construction– that it has three different kinds and sizes ofconductors in it woven in a most wonderfulpattern. There were many very fine small wiresfor the highs, somewhat fewer and coarserstrands for the mid-range, and really heavystuff for the bass.

I asked the obvious question, “Well then, whatkind of a three way electronic crossover do youuse after the amplifier to get each of the threesonic ranges into the “right” part of the wire,and again after the speaker wire (before theloudspeaker) to get all the sound back togetheragain at the speaker terminals?” You see, I wasreally worried about this problem. After all, Ican surely assume that without an electroniccrossover ahead of the speaker wire, that therewas a dire chance of accidently getting highsinto the bass frequency wires or getting mid-range into the bass wires, etc., and really ruin-ing the sound. And, I am sure that if you gotthose big nasty bass signals into that itty-bittyhigh frequency strands in the cable that youprobably would permanently damage the wiresand they would no longer be good for anythingmore useful than connecting the output ofatomic power plants to transmission line grids.I need not have worried! I was assured by themanufacturer that an electronic crossover forspeaker wires was unnecessary. It seems likethe sounds are really smart! The highs knowjust where to go – to the high frequency strandsonly. Likewise, with his wires, the mids andbass are magically and mysteriously directedonly to their appropriate sized conductors. Nointeraction was possible.

I restated the question, “You claim then thatyour high frequency strands will not pass basssignals, only highs?” I was assured that thiswas correct.

I then posed another question, “Would youthen assume that signals below 100 Hz are bassand would not go through your high frequencystrands? I was assured that was true. I thenproposed an experiment to confirm all thisgood data:

1. Take a section of the magic wire in questionand strip out two lengths of the high

frequency strands only and remove theinsulation from the ends.

2. Put one length in each hand of themanufacturer (after wetting hands withsalt water to assure good conductivity).

3. Plug other ends into a 110 volt 60 Hzpower outlet and see what happens!

Obviously, since the wire was claimed to notconduct low frequencies, and since 60 cycles isa low frequency, the manufacturer would notbe harmed and this would be a dramatic proofof his claims.

To my utter astonishment (ha - ha) the cablemanufacturer did not leap to perform myexperiment! Actually, he got red in the face,turned about, and stalked off! He was nothappy with my idea at all! I wonder why not?Could it possibly be that his “high frequency”strands will conduct lows (thus electrocutinghim) in spite of his claims? Could it be that hisclaims are false? Could it be that the highs,lows, and mid-range are getting all mixed up inhis expensive cables? Could it be that the entireconcept of hyper-priced “tri-axial” speakerwires is actually only hyper-bull? What do youthink? Caution! Don’t try this experimentyourself!

O.K. then, if you are still with me, you prob-ably agree that our worst remaining audiosystem problems are not the speaker wires orcables. What about your electronic audioequipment? You can read many advertisersupported high fidelity magazines and find outthat all audio equipment is essentially perfectand cannot be improved upon. You can readthe underground magazines and find out thatunless the equipment costs in excess of$20,000.00 that it is not even fit for use by yourGreat Aunt, unless it is at her summer cottageand she is not there hardly ever. (Class C.) Youcan get really confused and not know what tobelieve or who to rely on.

In general, we would advise you that the audioelectronics in your system is not perfect. Thelower priced receivers are not much better thanclock radios, and even much of the expensiveequipment is not capable of reproducing everynuance of “live.” However, there is a price topay for perfection, and you may not choose topay that price.

To be rational, we would suggest that you haveavailable, with careful selecting, audio elec-tronics, within your budget constraints andyour desires, that at the very least, is not theworst case problem in the reproduction chain,and thus, is likely good enough.

Is it the loudspeakers then, that is our worstproblem? They used to be, but not any more ifyou select carefully. Certainly even fine loud-speaker designs have their own individual limi-tations and distortions (otherwise they would

all sound identical) and your final choice isstill subject to your own subjective “likes” anddislikes – a kind of “pick your poison” prob-lem. But, there are really fine loudspeakersavailable at modest prices that are more ca-pable of realistic music reproduction than whatis demanded of them – they are higher fidelitythan the signal that drives them. And, fortu-nately, the limitations and colorations of goodloudspeakers seem to exist independently ofthe music – it is easy to tune these problems outand enjoy the music anyway. No, competentmodern loudspeakers are not the worst caseproblem.

The worst case problem in your system caneasily be your listening room. Ideally, youraudio system should be located in an anechoicchamber – a room completely free of reflec-tions and sound of its own. Not many peopleunderstand this concept, they assume that roomreflections are desirable, and also point outthat when a person is in an anechoic chamberand speaks, that his voice sounds strange,muffled, and dead. This is true, your voicedoes sound strange in an anechoic chamberbecause you are always used to speaking in areflective environment, but:

With an audio system, our sourceenvironment is not the anechoic chamber,but the environment of the space therecording was made in. We want to hearthe acoustics of the original environment,not the acoustics of our listening room,which was not part of the originalenvironment and thus is wrong. Obviously,if you record yourself talking in a reflectiveroom, and then play the recording back inan anechoic chamber, you will hearyourself speaking in the recorded room,and the sound will be natural.

Thus, your obvious goal in making yourlistening room sound better is to make itnot sound at all! We want to hear only thesound captured in the recording, notmodified by the acoustics of our listeningroom. With a little care it is pretty easy tomake our listening room “dead” andrelatively non-reflective. Then it isdefinitely not our worse case problem.

Next, we better consider our source material– our FM reception, tapes, records, and ourcompact discs. Is our playback quality prima-rily limited by the quality of our source mate-rial?

FM reception is actually a “second hand”source. It is obviously dependent upon thequality of the source the broadcasting station isusing and upon the engineering excellence oftheir transmission and your FM tuner. FM is an

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original source only for live broadcasts. Fortu-nately, I can assure you that if the live broad-cast is carefully engineered, if the station broad-casts for maximum fidelity and dynamic range(instead of for maximum car radio coverage),and if your FM tuner is of outstanding quality,then FM broadcast is not your worst caselimitation, it can be good enough to “put youthere.”

Analog tapes that we can actually purchase,especially cassettes, definitely are a worst caselimitation. Consider that the original masterrecording was done on a multi-thousand dollarstudio machine built like a tank, using one-halfinch tape running at fifteen inches per second.I have heard the playback of many real originalmasters made by master recording engineerssuch as Russ Borud and Bob Fulton. Let me tellyou that their originals are no problem at all.Unfortunately, you cannot buy the originals(in fact, you can only play them back a fewtimes before they start to obviously deterioratein quality). You can only buy “dubs.” In gen-eral you have only cassettes available. Theyare one-eighth inch wide and run at one andseven-eighths inches per second. A little mathtells you that the amount of data you can storeon cassette per unit of time is 32 times less thanwhat you can store on open reel. If it takes aprofessional open reel machine to make highfidelity recordings, what do you think you getwhen you cut the information by a factor of 32?You get low fidelity mud, of course. Cassettesare a worse case limitation. Luckily, we don’thave to use cassette as our sole source (unlesswe are a mid-fi audio store salesman).

We can turn to those tried and true (tired andwarped?) records. I don’t know where thesonic limitations of the best records are, butthere certainly are real barriers (mass) thatlimits our ability to get the information backoff the record – namely the mass of the play-back stylus and the mechanical limitations andresonances of the entire turntable - tonearmsystem. Records are a worst case limitation toaudio fidelity. Sure, each year there comesalong several more exotic, finicky, outra-geously expensive, and obscure record play-back systems alleged to eek a bit more resolu-tion from your records (assuming you have notalready worn them out on last year’s equip-ment). The trouble is you have got to push astylus around with soft plastic and there arereal world limitations as to how fast and howhard the record can push the stylus before thestylus starts eating the record and losing lots ofinformation. Obviously now, no stylus - arm -table is going to track the real dynamics of livemusic unless a zero mass retrieval system isperfected. Even then, we still have the massand energy limitations of the record cuttingmachine – what we really need is a zero masslaser record mastering and playback system.Wait a minute! We have that right now!

It is called the Compact Disc! We know wecan store music digitally encoded on a Com-pact Disc with really flat frequency responsebeyond the range of human hearing, with dy-namic range in excess of the capabilities of areal world listening room, and with vanish-ingly low distortion, channel interaction, andmechanical limitations. Any competent engi-neer knows we can reach 30 dB beyond thecapability of a vinyl record in every respect!The Compact Disc, itself, is not a worst caselimitation. In fact, it is easily our best methodof storing music.

Why then do so many “golden ears” hate thesound of CD playback? It is because theyhave been listening to a worst case limitation –the playback quality of all of the CD playersthey have ever been exposed to. The “experts”are making a great error – they are blaming theCD technology itself for flaws that only existin all of the totally inadequate CD players theyhave heard. They are throwing the baby outwith the bathwater.

What is the real problem? It is that all “off theshelf” CD players are executed to essentiallythe same low quality standards. Sure, the me-chanical and computer sections work just fineand really are capable of the sonic promises ofthe format. But when it comes to taking thedigital data stream, transferring it back to ananalog signal, filtering out the residual switch-ing data, and driving real world loads down-stream (such as your preamp), the CD design-ers have completely “dropped the ball.” Theyhave designed in tired old “Japanese receiver”60 dB dynamic range analog stages thatabsolutely strangle the music coming out ofthe CD player. Your CD player may have a 90dB dynamic range “specification” but only onsimple sine waves. On real music, your CDplayer is “stealing” and scrunching off 30 to 40dB of dynamics and resolution from every discyou play! Cheap IC output stages simply can-not supply the dynamic current to drive thenecessary internal filters fast enough withoutgoing into hard internal slewing and currentlimiting. In addition, you simply cannot usehigh Q filters with high frequency resonantpeaks in an audio application. Furthermore,you cannot “fix things” by tacking on addi-tional circuits after the original CD audio-filtercircuits as is done in several very expensiveBritish CD players. The damage has alreadybeen done!

What must be done is to replace all of theaudio and filter circuits with complete newaudio and filter circuits that have the followingcharacteristics. The audio circuits must be 100dB dynamic range truly high fidelity designs,not “mid-fi” afterthoughts. The audio circuitsmust be able to drive the required filters with-out limiting under dynamic music conditions.The filters must be critically damped (Q=0.5)

with no ringing at all. The audio circuits musthave an independent power supply, free ofdigital switching trash. When you experienceCD playback that is finally “right,” you willimmediately know that a great step toward“you are there live” has been made. You willrealize that previously the source playbackhad been your worst case problem!

There is a CD player available right now thatmeets the above described criteria – the Tran-scendence CD Player. It costs $795.00 out-right or $595.00 to install our five new circuitboards in selected Philips (Magnavox) units.Call us for application details before ship-ping! When you hear it, you are going to throwall your records away because it will makethem sound like Edison cylinders! It puts you“in the record booth” with studio recordings,and “in the hall” with good live acoustic per-formances. Sure, you will hear all the engi-neering flaws in poorly executed material, butas a “visitor to the session” not as a captive ofa hi-fi system. It is a new experience. It isprobably our best new product, and worksgreat even when the rest of your system isn’toutstanding. And although it greatly extendsthe range of your system (much more powerfuland clean bass and clear highs) with outra-geous transients and dynamics, it seems tomake your amplifier sound more powerful. Itdoesn’t stress your system; it unleashes yoursystem.

Your audio system can be no better than yoursource material, and your ability to play backthat source material. We now recommend thatyou start with the Transcendence CD Playerfirst, no matter what the rest of your system is.With stunningly better source playback, youwill think you installed an all new system.

We have got one other new product to an-nounce now, the Transcendence 110 Pream-plifier. We have installed five new Transcen-dence circuit boards in the Hafler DH-110preamp: a new shunt regulated power supply,two new Transcendence phono preamplifiers,and two new Transcendence line preamplifi-ers. We interface with and salvage all of Hafler’sswitching and control functions. It sounds, ofcourse, just like our other Transcendence Se-ries Two preamps, but is prettier and has com-plete full functions. The price is $895.00 out-right, or $545.00 to install our new circuits inyour stock Hafler DH-110. It is available rightnow!

Frank Van Alstine

VOLUME FIVE NUMBER EIGHTAUGUST, 1986

One reader wrote to me last week regarding theJuly, 1986 issue of Audio Basics wonderingwhy I did not say more about treatment of yourlistening room.

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The reason; I did not want to repeat myself. Ihave already discussed the basics of room“taming” in the July, 1983 issue (VolumeTwo, Number Seven). Yearly back issue setsof Audio Basics are still available at $15.00 peryear delivered in the continental U.S.A.

I have talked to many of my clients and readersover the years about their listening rooms on anindividual basis. These conversations pointout a common problem – people simply do notwant to do what is necessary to make theirrooms sound better. They like their glass, tile,chrome, and hardwood surroundings. Whilethat can be just fine as a human environment,it is not fine as an audio system environ-ment. In a bright, reflective listening room, the“sound” of the room will always dominateover the sound of the system and high qualityplayback equipment just won’t do you muchgood at all. If you want good sound, you mustcreate a good sounding room first – actually aroom that does not "sound" at all.

I have got a bunch of products that I havelistened to in house recently that will not helpyou get good sound.

I will start with Reference Recordings. I havementioned in the past that I was underwhelmedwith vinyl records made by Reference Record-ings because I thought the special tape re-corder used sounded like a Sony 350 with wornheads. Now I have had a chance to listen to anew RR Compact Disc, RR-12CD “DAFOS.”I find I was wrong about the tape recorder used.Keith Johnson’s “unique focus gap analoguerecorder” doesn’t sound like a Sony 350 withworn heads, it sounds like a cassette recorderwith worn and magnetized heads. There is nodynamic range, the bass is pure rubber, and thehiss level on a CD reminds me of my $49.00Sharp RT-100 cassette recorder using RadioShack tape and with Dolby off. You have tohave more than just good harmonic balanceand definition to qualify for realistic audioreproduction in my book. You have to get thedynamics right too! I have yet to hear a Refer-ence Recording that qualifies as “high fidel-ity.”

Another tape recording format that just doesnot make it, I am sorry to report, is the currentgeneration of Kodak 8 mm PCM video tapedecks. I have discussed the technical details ofthis system previously in Audio Basics, but lastweek was my first chance for a hands onevaluation. I did not evaluate the system forvideo performance, just to see how well itcould be used as a digital audio tape recorder.

As I previously mentioned 8 mm PCM videouses an eight bit digital record and playbacksystem, with built in compression and expan-sion circuits, giving, in theory, a 80 dB dy-namic range audio recording capability withflat to 15,000 Hz frequency response. If ex-ecuted properly, this should be good enough to

give much better audio results than any analogcassette deck.

In practice, Kodak’s version of 8 mm PCMvideo is useless for high fidelity audio repro-duction. They have made a big mistake. Thereare no record level meters or audio level con-trols on their deck. Instead, you get an auto-matic record level control built in!

An automatic level control is what you get onlittle $20.00 hand held cassette recorders. It isa circuit that drastically compresses loud pas-sages to not overload the tape, and drasticallyexpands quiet passages to make them louder tocover up tape hiss. It is fine and dandy doingcausal voice recording on a toy portable cas-sette recorder for “talking letter” purposes,especially when used by somebody who doesnot understand how to record.

For high fidelity purposes, the automatic levelcontrol circuits are fatal! All of the dynamicrange of the music is killed. It turns a CD intotable radio music, with all contrasts betweenloud and soft removed, and with all big dy-namic transients removed. Thus the Kodak 8mm PCM system cannot record high fidelitymusic at all!

It is not possible to tell how well the 8 mmdigital record and playback circuits are work-ing. You simply cannot “hear past” the auto-matic level control, which is ahead of thedigital circuits. For your information, Sonydoes make one model of their 8 mm PCM deckthat does have record level controls and ametering system. Automatic level control cir-cuits are not used. It may have a chance ofworking for high fidelity audio recording pur-poses. I have not had the opportunity to evalu-ate the Sony system. I will report further hereinwhen I do.

I should remind you that the Sony PCM 501 ESdigital audio processor works just great forhigh fidelity recordings. When used with agood video tape recorder (need not be a hi-fistereo model or high video resolution model)you can record clones of CDs! I now have over140 Compact Discs digitally recorded on PCMvideo tapes. This extension to my music col-lection has paid for the Sony processor manytimes over.

I am still happy with the Sony Beta Hi-Fiprocess for high fidelity audio recording. Com-pared to the original CD playback, it veryslightly dulls the top and very slightly com-presses the most dynamic bass passages, andyou can sometimes hear the “swish - swish”sound of the internal noise reduction circuitsworking when high frequency attacks comeout of a silent background. But, the 80 dBdynamic range of this format does give accept-able musical results. In contrast, an audio cas-sette deck simply cannot record a CD, thedynamic contrasts are “out of range.”

Yes, I know that the last issue of Stereophilestated that Hi-Fi Beta was not as good as a goodcassette recorder. But they are all screwed up!Case in point – my “adventure” at the June,1986 C.E.S. show at the Krell display. Therethey were, two mono amplifiers (costing$10,000) as big as, and weighing as much as,steamer trunks full of lead scraps. They weredriving Apogee ribbon planar loudspeakers.Unfortunately, the system sounded like it wasbeing driven by two steamer trunks full of lead(with a Sony Walkman somewhere inside con-nected to the loudspeakers). The system hadthe dynamic range of a clock radio. I askedpolitely if the Krell amplifiers were in useelsewhere at the show as I wanted to hear themon full range dynamic loudspeakers. I alsomentioned that the “cello” music sounded aw-fully pinched and compressed (my sister, amusic teacher, plays the cello). I was immedi-ately “jumped on” and told, by the group therethat it was not a cello playing, but a string bass!You sure could have fooled me! In fact, thesystem did – it was so terrible that I reallycouldn’t tell the difference between a cello anda bass (the system had no bass!).

Since the esoteric experts there seemed to behappy with their table radio dynamics andrange, I left for more promising exhibits. Ofcourse the new editor of Stereophile has glee-fully used this incident to malign me in his firstissue, writing it up with somewhat differentemphasis and choice of adjectives (I seem to benasty, vicious, and deaf). Anyway, the point isthat if your “ideal” is a pale, compressed ver-sion of live, then an audio cassette recorderwill do just fine (as it does for Stereophile).But, if you demand that an audio system de-liver the dynamic contrasts and attacks of live,then an audio cassette recorder doesn’t hack itat all.

One other “curious” thing about the last issueof Stereophile. This was their C.E.S. showreport issue and the show was written up inde-pendently by several different reviewers. Al-though all kinds of obscure products werenoted, an interesting, and well promoted newproduct “did not exist” as far as Stereophilewas concerned. B&W and the new Matrixdesigns were not mentioned at all!

Sure, the show is big and nobody can possiblyevaluate everything there carefully, it is nothumanly possible. Thus, I can understand thata writer might miss B&W by accident, but alltheir writers “missing” B&W?

This omission reminds me of a statement madeto James Bond by Goldfinger after Bond hadbeen captured for “snooping.” Goldfinger said,“once is chance, twice is happenstance, butthree times, Mr. Bond, is enemy action!”

I am getting a better feeling of why so manyesoteric writers and manufacturers do not likeCompact Disc as a musical source. Several

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clients have brought in pieces of esoteric equip-ment recently for us to evaluate and it is be-coming obvious to me that the dynamic poten-tial of CD is getting a lot of highly regardedequipment into real trouble.

A recent Belles preamplifier scrunched thedynamic range and lifelike transient capabilityof our CD player back down to that of a vinylrecord, but with a reduction of definition and“space” to even worse than on the record. Atleast the line section was pretty smooth andneutral. The phono section of the Belles wasnot even that good, sounding “detailed” (hardsolid state edge on everything). The problemswere not terribly obvious, just enough to changelistening to music to listening to a hi-fi system.

A Conrad-Johnson PV-4 preamplifier soundedvery much like an original Super-Pas pream-plifier, with perhaps, a little more coloration(not unpleasant). It did not have the stabilityand freedom from on or off transients that theSuper-Pas does, and it costs a whole bunchmore. Needless to say, it did not keep up withan improved Super Pas (plans for same laterin this newsletter!) or a Super Pas Two, and it

did not “like” a CD player at all. It might haveliked a very expensive new Nakamachi CDplayer we recently evaluated. This was prob-ably the smoothest and highest resolution stockCD player we have heard. Unfortunately, theNakamachi compressed dynamics and tran-sients substantially, and lost the solid bassfoundation. It might be a good match for audio-phile having better bank accounts than ears. Ifyou have invested megabucks into smooth, butprofoundly underdynamic equipment like Krelland Apogee, and pay no attention to “live” (ifyou get to occasional concerts at all) then a CDplayer like the Nakamachi might suit you justfine – you will never know what you aremissing.

Gee, this issue is starting to sound pretty nega-tive. Lets talk a bit about a new product that Ifind to be very (but not completely) positive. Ifinally, at long last, have received my firstshipment of B&W Matrix 1 loudspeakers.They are great loudspeakers performing evenbetter than my impressions of them at theC.E.S. show. They do have some use limita-tions we need to tell you about first:

1. They have a four ohm impedance ratingand are only 85 dB efficient. Thus, theysimply cannot be used on a marginalamplifier or with most receivers. Theirpower demands will likely be more thanmost low powered amps or receivers canhandle safely. If you push them hard on anamp or receiver with marginal current orheat sink capabilities, you will riskoverheating and damaging your amplifier.

2. You will really need a big amplifier (ourMos-Fet 200C or better) to drive two pairsin parallel – as this is a 2 ohm loaddemanding overkill heat sink design andgobs of power at the same time.

3. The special purpose marble base standsfor the Matrix 1 are not yet available.Evidently they had a lot of breakageproblems in early production and theperfected stands have not yet arrived in theU.S.A. Thus, you will have to put up witha less than ideal location for the speakersuntil the stands come in. These speakersreally do like to be kept away from surfaces(walls, floor, and other components) to

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avoid putting back into the sound field theresonances and colorations that have beenremoved from the Matrix cabinetthemselves.

Enough of negatives, now you need to knowwhat the Matrix 1 loudspeakers do correctly –essentially, just about everything.

The Matrix 1 is a small loudspeaker (16" highx 9" wide x 12 5/8" deep) weighing 22 pounds.It uses a 150 mm homopolymer polypropylenewoofer-midrange and a 25 mm polyamide dometweeter. Its sensitivity is 85 dB and its imped-ance is 4.5 Ω (resistive). It has a very flatfrequency response (+ and - 2 dB from 80 Hzto 25 kHz) with unusually linear dispersioncharacteristics (its response is constant even300 off axis). Our selling price is $900/pair(Matrix 1 stands are $180/pair extra).

For those of you familiar with the B&W line,I can point out that the Matrix 1 is simply abetter loudspeaker in all respects than all pre-vious models up to and including the DM2000s,which we sold for $1200/pair!

The first impression is that the Matrix 1 hasextraordinary resolution. It resolves small sig-nal detail (from top to bottom) like an 8" x 10"portrait camera resolves landscape detail (asused in Arizona Highways). Not “detail”bright and hard , but detail soft and clear –simply “more of the music” laid out for you toperceive.

Second, the Matrix 1 provides extraordinarymusical space. It does not play what is notthere. Thus, it “plays” the time and spacebetween notes and performers better. You geta better sense of the music “floating” in yourlistening room with no audio system there atall. Essentially, it images better.

Third, it plays much wider range than youwould ever suspect a box this size could do. Itsounds like a big loudspeaker. The depth, defi-nition, reach, and solidity of the bass responseis striking. It reaches down further than aDM3000, but with less “power.” It also playswith excellent dynamic authority, not “shut-ting down” when played loudly or compress-ing dynamic transients. The DM3000 will playlouder and with greater dynamics yet, but notwith the absolute clarity of the Matrix 1 (herewe reach a trade-off in performance). Note thatthe Matrix 1 does have electronic protect cir-cuits that turn off the tweeters under overstressconditions – which clues you in to quit doingbad things to your system.

Thus the Matrix 1 is a really useful product. Itwill give you “big and expensive” loudspeakerperformance at a lower price than possiblebefore, without demanding the space of a bigloudspeaker. It does demand a high qualityamplifier! Any of our Mos-Fet or Transcen-dence amplifiers will work just fine (higher

power will give you greater dynamic transientcapability) for a single pair of Matrix 1s. If youwant to run two pairs at the same time, theminimum amplifier recommended is the Mos-Fet 200C or Transcendence 200 as the extracurrent and heat sink capability is necessaryfor the sustained 2 ohm load at high power.

One further thought. The higher resolutioncapability of the Matrix 1 allows you to hearbad program engineering “better” than ever.Poorly produced source material will soundjust terrible with the Matrix. It is for qualityprogramming only!

Now, for something completely different – anupgraded do-it-yourself circuit for our origi-nal Super-Pas preamplifier only! The fol-lowing circuit improvements will give youroriginal Super-Pas nearly the dynamics andresolution of the Super-Pas Two (within thelimitations of the power supply and boardlayout). The necessary parts are going into thecomplete original Super-Pas do-it-yourself kitright now, at no increase in price (still $125.00).The new parts required for upgrading the audiocircuits of the Super-Pas described herein areavailable from us for $35.00. Note that therehave been several upgrades to the Super-Pas inthe past, including the photo-flash power sup-ply parts and the LED pilot light improvement.Those parts are still available separately aspreviously described. Very old Super-Pas units(1979 thru 1981 production) may need othercircuit changes. If your board layout does notmatch the diagrams included in this issue, callus for advice.

Note also that the following improvementsapply to an existing Super-Pas unit only. Ifyou are starting with a stock PAS preamp, youwill need our complete Super-Pas kit and plansset instead of the following instructions.

Note also that you must have the electricalassembly skill to remove parts from the circuitboards and to solder in new ones withoutdamaging the foil paths or shorting anythingout. This upgrade will not fix a defective unitand mistakes can ruin a unit now workingproperly. We cannot guarantee your work-manship.

1. Remove your Super-Pas from your system,remove the top and bottom covers, anddischarge the power supply capacitorsby shorting the eyelets marked B+ on thesketches (on PC-5 and PC-6 cards) tochassis ground through the 100 ohm 2watt resistor supplied. Touch one lead tothe chassis and the other lead to the B+eyelets for several seconds (hold theresistor by its body). Always repeat thisprocedure any time you work on theunit. The photoflash power supplycapacitors “hold” an awesome charge evenafter the unit has been turned off andunplugged for a long time. It is unsafe to

work on the boards with the power supplycaps charged.

2. Locate the two 10 ohm resistors on theback panel between the audio output jackground lugs and the next ground lugs over(Brown-Black-Black). Remove these tworesistors and replace them with jumperwires taking care that the jumper wirescannot short to the “hot” side of the jacks.This change will substantially reduce“crosstalk” between unused sources.

3. Now you will be replacing 16 capacitorson the two audio boards and 2 capacitorson the blend switch (or on the balancecontrol on some units) as follows. Refer tothe board layout sketch and note that thereare two of each “C Number” to bereplaced.

A. Locate your PC-6 board (under theselector switch) and the attachedsketch thereof. Locate and remove thetwo C7 capacitors and replace themwith two 0.33 µF 50 or 100 volt filmcapacitors (334).

B. Locate and remove the two C8capacitors and replace them with two0.1 µF 250 or 400 volt film capacitors(104).

C. Locate and remove the two C11capacitors and replace them with two2.2 µF 250 or 400 volt film capacitors(225).

D. Locate the two 10 pF C12 disc or micacapacitors on the blend control or onthe balance control. Remove themand replace them with two 100 pFmica capacitors.

E. Now refer to the sketch of the PC-5line board and the board itself. Locateand remove the two C13 capacitorsand replace them with two 0.33 µF 50or 100 volt film capacitors (334).

F. Locate and remove the two C14capacitors and replace them with two0.047 µF 250 or 400 volt filmcapacitors (473).

G. Locate and remove the two C15capacitors and replace them with two2.2 µF 250 or 400 volt film capacitors(225).

H. Locate and remove the two C16capacitors and replace them with two10 pF mica capacitors.

I. Locate and remove the two C17capacitors and replace them with two3.3 µF 250 or 400 volt film capacitors(335). You will get a better “fit” onthe new parts by locating thembetween Eyelet 11 and the hole just

Audio Basics Complete 1986 Back Issue Set Page 24

beyond Eyelet 12, and betweenEyelet 4 and the hole just beyondEyelet 5 respectively, instead of intheir original physical locations. Notethe new C17 R locations on the sketchto be used instead of the original C17locations.

This completes the project. All test voltageswill remain the same as before. You shouldnotice a big improvement in dynamics, range,bass extension, and resolution.

Frank Van Alstine

VOLUME FIVE NUMBER NINESEPTEMBER, 1986

It has been a very busy month for me, espe-cially with paperwork. I have been buried inthe stuff putting the final touches on our newcatalog.

We are changing our name to Audio by VanAlstine. We are doing this to end the confusioncaused because everybody knows about VanAlstine made audio products but nobody knowswhat “Jensen” has to do with this. Actually,Paul Jensen was my partner for years startingin the early 1960’s until 1973. Now, I get fartoo many calls from people wanting repairs ordiscount prices on Jensen car speakers andJensen car radios. Some even get upset with uswhen we give them the bad news that we do notdo warranty work on Jensen car radios. Chang-ing our name to Audio by Van Alstine willend this problem, I hope.

You know that we keep telling you to call usbefore returning equipment for service sowe can help you find out if the problem is“real” or not. We also ask that you tell abouteverything in your system if you have a prob-lem to help us diagnose what the cause is. Thismonth, we had two rather strange service prob-lems that we could have solved easier if wewould have had all the data first:

We updated a client’s Transcendence 200amp and Transcendence preamp to ourSeries Two circuits. When the clientreinstalled them, he really did not like thesound. He even went to the considerableeffort of hand carrying them back here(two 100+ mile round trips) for us to checkout again. Of course, both units tested andperformed perfectly here. The client reallywas not very happy with us. But with thedata he gave us, we could find no goodreason for his negative evaluation of theupgraded equipment. A few weeks laterwe learned the real reason why the systemsounded bad. The client had installed aPioneer electronic crossover in the systemat the same time as he reinstalled ourequipment. He didn’t tell us that! Of coursean audio system will perform to the quality

standards of the worst piece of equipmentin the system (like the weak link in achain). When the client removed thePioneer unit, the sonic quality immediatelyimproved. If we had been given all the datawe would have saved that client (andourselves) a lot of time and trouble. Weneed all the data to serve you best!

Another client called us to complain thathis amplifier was intermittently going“beep” every 30 seconds or so. He claimedthat the problem had been isolated to ouramplifier. Although we could see nopossible cause for this problem, we didauthorize the client to return the unit to usfor testing. He had it all packed up to shipto us when he realized that the systemwas still going “beep” even with theamplifier out of the system! It turned outthat the “beep” was coming from a nearbysmoke detector with a low battery (theintermittent “beep” is the signal the smokedetector makes to tell you it is time toreplace its battery).

It is so easy to jump to conclusions instead ofcarefully evaluating the situation when youraudio system doesn’t seem to work right. Weknow it is very frustrating when you don’tseem to get the sound you paid for. However,when things seem to go wrong, don’t get mad,instead, get analytical! You will get a betterfix.

Next is a little technical formula to tell youhow much power a given fuse size will pass.This will allow you to install the smallestpossible quick blow speaker fuses in yoursystem to provide maximum protection to yourspeakers and amplifier. The formula is:

POWER = CURRENT SQUARED TIMESRESISTANCE. P = I2xR

Power is the continuous average power thefuse will pass. Current is the rating of the fusein Amperes. Resistance, in this case, is therating of your speakers, in Ohms (usuallyeither 8 ohms or 4 ohms). Thus, a 2 amp fusewill pass 32 watts into an 8 ohm loudspeaker(22x8=32) while a 4 amp fuse will pass 128watts. Note that the power goes up exponen-tially with fuse size, not linearly. Thus usingtwice as big a fuse does not pass twice thepower, but four times the power. If you arenot aware of this, it is easy to install far too biga fuse and fail to protect your system.

In our reference system, we can use 2 ampquick blow fuses on the T-500 driving theB&W 808s to outrageous dynamics withoutever blowing fuses. This is because even whentransients are at very high levels, the averagepower is much less than the 32 watt capabilityof the fuse. You don’t need sustained highpower for realistic musical reproduction, youneed sustained high quality and stability.

Good news for those of you looking for a SonyPCM 501 ES digital audio processor. QAUDIO , 95 Vassar Street, Cambridge, MA02139 (phone 617 547-2727) has them avail-able. This is a company I have dealt with foryears, owned by Bob Heenan. They are reli-able and keep their promises. I now have over500 hours of Compact Discs transferred todigital video tape with the Sony unit, and amgetting record and playback quality that isnearly a clone of the original CDs. I highlyrecommend this unit as the best possible methodof tape recording for you. Its cost, along withany good video deck (need not be a “Hi-Fi”deck as the Sony PCM unit uses the videosection, not the audio section) simply wipesout any consumer audio cassette or open reeltape recorder and at a lower total price than theso called high end cassette recorders.

Did you know that it is very easy to set therecord levels on the Sony PCM unit whenrecording from a Compact Disc so that it willbe impossible to overload the PCM tape? Youneed to know two things.

The maximum “0 dB” level on a CD cannotbe exceeded because once all 16 bits areturned on, that is an absolute maximumoutput level.

You can purchase test CDs (Denon#33C39-7441 & Denon #38C39-7147) thathave “0 dB” levels on them.

Thus, you can pre-set the record level using thetest CD and be assured that no music CD yousubsequently record with that CD Player canhave an output in excess of the previously set0 dB level from the test disc.

There is one “catch.” The Sony digital pro-cessor does use about 10 dB of high frequency“pre-emphasis” and “de-emphasis” in record-ing and playback. Thus, if you use a 1 kHz testtone for setting levels, there is a rare chancethat a very high level, very high frequency tonecould still overload. To be really safe, presetthe record level using the 0 dB white noise or3 kHz tones. Of course if you switch CDPlayers you will have to re-calibrate, as theoutput levels from different CD players canvary.

I have previously “panned” Compact Discsfrom two different companies, Sheffield Labs,and Reference Recordings. My negative com-ments apply only to their analog masters. Ihave recently heard several digital mastersfrom both companies, and the sonic and engi-neering quality is excellent and recommended!

If you have been a steady reader of AudioBasics, you will know that it is very rare for an“off the shelf” piece of audio electronics toarrive here that we think very much of. Wellfolks, an audio amplifier has arrived here thatis simply great! It is the new Hafler MA-1Mobile Amplifier.

Audio Basics Complete 1986 Back Issue Set Page 25

This is a 100 watts per channel (into 4 ohms) –about 70 watts per channel into 8 ohms – caramplifier. It is very, very good. It is so goodthat many users will not realize just how musi-cal it is because the rest of their automobilesystem will not be its equal. I am listening tomy second sample of the MA-1 right now as Iwrite this (the first was already delivered to aclient preparing a rally car for a cross Canadaand Alaska 4000 mile endurance rally – wewill know soon how the MA-1 stands up underthat use condition)!

I am not using the Hafler MA-1 in my car, yet!For now, it is hooked up in my home referencesystem driving my B&W 808 loudspeakerswith a Transcendence CD player as a source. Itdrives the 808s better than any other “outside”amplifier we have tried them with. Yes, it iscleaner than Hafler’s stock home amplifiers(and they are all quite good and are goodvalues).

It has just outstanding bass dynamics and drive(no boom, no mud, and it never gives up). Themidrange is clear, with spacious imaging andexcellent transient detail with no obvious col-orations at all. The highs are very extended,very pure, and very free from nasty edges. Itsounds amazingly solid, and handles big dy-namic transients just fine – it sounds muchmore powerful than its rating.

It is not as high a definition as our amplifiers,but without a side by side comparison, thedifferences are not severe. Certainly it is amore honest amplifier than anything else I canthink of, price not considered. Lets put it thisway, its level of performance is great enough(especially considering its price) that I don’thave a high priority for tearing it apart andrebuilding it with our circuits. Its already goodenough (especially when you consider that thecar electronics ahead of it and speakers after itprobably are now the “weak links” in anyevent).

The Hafler MA-1 is a discrete power mos-fetdesign with a switching power supply to effi-ciently “step-up” the car voltage enough tomake some real power. Of course the currentdraw from your battery at full power is large (inexcess of 15 ampere) so don’t plan on “all daysound at a beach party” from it with yourengine off – you will end up with a deadbattery! It is a flat little package (about 12"long x 8" wide x 3" high) and the entire case isan extruded finned heatsink. (It doesn’t getexcessively warm driving the 808s or the 4ohm Matrix 1s.) One end has gold plated RCAinput jacks and level controls. The other endhas an output terminal block, battery connec-tions, a LED indicator lamp, speaker and powersupply fuses, and a connection for remote turn-on and turn-off from your radio head. It willnot be available as a kit. There simply is not

enough for a kit builder to do to give any costsavings.

The Hafler MA-1 Mobile Amplifier has a listprice of $400.00. It is available right now! Itmakes other car radios look and sound like,well, car radios. Mine will be going into theQuattro very soon to drive the B&W MASSLM60s. I can hardly wait!

I have now had the opportunity to evaluate theentire new B&W Matrix line, the Matrix 1 (ourprice $900/pr), the Matrix 2, and the Matrix 3.

As discussed last month, the Matrix 1 is a realwinner – a clear, dynamic, big sounding speakerthat transcends its size and price. It outplaysthe older B&W models up to and including theDM2000 and has higher resolution than theDM3000 too (although not as big and dynamicsounding).

The Matrix 2, essentially sounds just like theMatrix 1, perhaps a tiny bit more efficient andcapable of playing a little bit bigger and louder.However, it costs a lot more than the Matrix 1and I cannot justify its increased price versusits small (if any) increase in performance. Idon’t plan on stocking the Matrix 2 because theMatrix 1 works so well for less money.

The Matrix 3 is a completely different kind ofloudspeaker sonically. It is a much more “Brit-ish” sounding piece, reminding me of Pro-Ac,JSE, and KEF sound. It has excellent defini-tion, detail, and imaging, but is much more“restrained” than loudspeakers I really like. Tome, it is too “polite” – it doesn’t go “crash-bang-boom” when I think it should. Many willviolently disagree with me about the Matrix 3,especially those that favor electrostatics andmoving coil cartridges – they will probablyreally like the Matrix 3s best of all. I don’t.

I don’t plan on stocking the Matrix 3 loud-speakers because they simply do not “fit in”with the overall sonic character of an audiosystem that I want to present. My demos are forsale at a very large discount (call for details). Ineed the floor space for products I do favor. Ofcourse the demo Matrix 3 units are in brandnew condition, with all paperwork and acces-sories, and in their original cartons and willcarry a new warranty.

One additional new B&W product does workexactly the way I like – the heavy marble basestands for the Matrix 1 loudspeakers. They area “bitch” to assemble (you will need a bigPhillips screwdriver) but once installed, theymake the Matrix 1s sound even clearer andmore solid than ever. They are worth our $180/pair price. They are coming in very slowly (we

have received only one pair so far and thosehave been delivered) so wait patiently for them.

I just got in a big shipment of an older (but verygood) model B&W loudspeaker stand, theSTAV-22 (made for the discontinued DM22loudspeakers). These stands have a round,brown fabric covered base, a tubular pedestal(about 14" high) with a metal speaker base-plate. They are sturdy and easy to use, and canbe sand or lead shot filled for additional stabil-ity. They work very well with DM100s,DM110s, DM220s, Matrix 1s, and Matrix 2s(and other brands of speakers too). We got aspecial deal on them we will pass along to you– $35.00/pair delivered in the continentalU.S.A. or, better yet, free, with the purchaseof DM110, DM220, or Matrix 1 speakers(while our supply lasts).

Now I would like to tell you about a nasty littleproblem affecting the compatibility betweencertain CD Players and certain CD discs them-selves, a problem that can cause some CDs tonot load properly in some CD players. First ofall, take a very close look at the bottom (play)side of several of your Compact Discs – espe-cially in the area between the hole and wherethe data starts – the area where the disc restsupon the hub inside the player. Notice thatmany discs are not flat and smooth in thisarea! They have ridges, grooves, and recessedareas. The radius of these ridges and recessesvary from sample to sample. If the radius of aridge, groove, or recess randomly happens tobe about the same as the radius of the hub inyour particular CD player, then it is very pos-sible for that CD to sit “crooked” on the hub,wobble when spun, and require more laserfocus servo-adjust than the machine can pro-vide.

In this case, the CD will not load, or if it loads,it will cause many play errors – especially onthe later (outside) tracks where the “wobble”error is much larger.

Randomly, that same disc may load just fine,or, with a few discs, never load properly at allin your particular machine. That same CD maywork just fine in another CD player becausethat CD player has a slightly different size hub.

Philips, for example, has made minor changesin their hub size in production several times toovercome this problem – but each time theyhave been “defeated” by yet another CD press-ing plant making yet another random change inthe size of the groves or recesses in the CDsthey make. It seems as if the CD player manu-facturers and the CD manufacturers are notcommunicating well!

In any event, if a certain CD doesn’t work wellin your CD player, do not assume that the CDor the CD player are defective. The chances arethey are simply incompatible. Another load

Audio Basics Complete 1986 Back Issue Set Page 26

problem is caused by CDs that have too largea center hole. This can cause an “out of round”load condition with a lateral “wobble” againoutside the capability that the laser servo-drivecan follow. North American Philips engineerstell me they are seeing more “out of spec” CDcenter holes as more pressing plants come online and as production increases.

Another problem that can cause unreliable CDloading and performance is simple to cause,but hard for the consumer to fix. It is dirt –especially dirt specks on the play side of theCD. If there is a bit of foreign matter on thebottom of your CD, and if it is transferred to,and sticks to, the hub of your machine whenthat CD is loaded, then every CD sitting on thehub in your machine will sit “crooked” and behard to load and play until the debris is re-moved. The cure is to clean the hub. To do this,you must have access to the top of the hub,which, in front loading machines, is “buried.”Owners of old top-loads have it made – theycan inspect and routinely clean the hub easily.With front load machines you must remove thecover and the hub clamping mechanism –typically a job for a repair shop. The marketplace has demanded front loading machinesand I don’t think there are any top loadersbeing made any more. The moral you mustalways inspect the bottom side of your CDsbefore loading them and clean off any dirtspecks before they get transferred to thehub inside your machine. A little care herewill really help keep your machine playingreliably.

We are seeing more advertisements for “spe-cial CD discs” to be stuffed into your machinealong with the CD you are playing. Theseblank discs are claimed to improve the perfor-mance by “shutting off light leaks,” “stabiliz-ing and damping” the player, and so on. Do notbelieve these claims and do not use thoseafter market blank discs (or stack two CDsin the player) at all.

Your CD transport is designed for the thick-ness, mass, and inertial loads of a single CDonly! Doubling the thickness the mechanismhas to handle may deform internal clamps andtheir tension springs. It may cause excess mo-tor bearing wear. It will screw up the motorservo-drive which was not designed to handletwice the inertial loads of normal – causingexcess read errors. The extra mass and thick-ness can cause your machine to jam com-pletely, and you also risk scratching your CDs.

These excess strains and loadings certainlymay change the sound of your CD playback.They certainly won’t make the playbacksound better. If you really believe that screw-ing up the system gives you better results, thendo I have a great deal for you – a handful ofsand to dump into the oil filler of your car

engine – guaranteed to change the perfor-mance of your engine!

The Carver Company has a big advertisingpush going right now claiming that they havean amplifier that Bob Carver has made soundidentical to some esoteric and expensive monovacuum tube amplifiers (Conrad-Johnson sothe rumor goes), and that the engineering wasdone in a hotel room while Bob Carver wasproving his claim that he could duplicate thesound of these vacuum tube amplifiers to theeditors of Stereophile, on the fly, while visitingthem. These claims, and the reprint fromStereophile verifying them, appear to be veryimpressive. I have several observations:

1. Bob Carver is a very good engineer andis a very good salesman. His level oftechnical competence is so much higherthan that of most audio writers that hisvisit to them must be like the early explorersshowing flashlights to the natives ofBoreno.

2. Carver’s job was not to come up with abetter amplifier , but a much easier task –simply to match the sonic effects of thedistortions of another imperfect amplifier.

3. A lot of different shades of gray lookexactly the same when you are in the dark.Carver did not have to get an exact match,only a match better than the distortions inthe rest of the system. Obviously, anydistortions in the source material, in therecord player or CD player, in thepreamplifier, and in the loudspeakers thatwere greater than the difference indistortions and colorations in the twoamplifiers under test would mask out thedifferences between the amplifiers. Anextreme example – if you wanted to use akiddy phonograph as a source, you couldget an exact sonic match between anynumber of amplifiers used after it withouttrying at all. This is the reason that wealways tell you to “start at the source andwork downstream” when improving youraudio system. We know, but most“underground” writers seem not to know,that a properly designed CD player makesvinyl records functionally obsolete. Isuspect Mr. Carver would have a muchtougher time getting an exact subjectivematch with our CD player as the source.We would shine some light on those shadesof gray.

4. Getting a “null” match between the inputand the output of an amplifier (or betweentwo different amplifiers sharing a commoninput signal) does not mean that alldistortions or differences have beeneliminated. At least one common andsevere source of distortion has beenoverlooked and is not taken care of by the

apparent “null” – namely dynamic inputimpedance distortion.

As we have discussed herein in the past,one distortion that happens when thefeedback loop of an amplifier fails is thatthe input impedance of the amplifier goesto flanders – going to some low or highvalue and loading down the source. Wehave shown that when many amplifiers tryto drive a capacitive load, for example, theringing that occurs at the outputs reflectsall the way back to the inputs, causingringing to occur in the driving signal too!In other words, the internal distortioncauses the input signal to distort too!Now, even if you can null any differencesbetween the input and the output, or nullthe differences between two amplifierssharing that input, you have not nulledthe input distortion! You can get the twoamps to sound the same, but only whilethey are sharing the same predistortedsignal. In general the sonic effects are acombination of the worst case subjectivedistortions of both amplifiers. However,the placebo effect continues to operate.Once the evaluators are convinced that nodifferences can be heard, differences won’tbe heard.

5. Finally, none of the above observationsdeny the possibility that Bob Carver didnot get an exact match between the soundsof the amplifiers after all. He may havereally done it. However, I am not so surethat I want an amplifier that sounds justlike an expensive tube amplifier. I wouldprefer an amplifier that has no sound at all,that just reproduces exactly the sourcemusical material.

Frank Van Alstine

VOLUME FIVE NUMBER TENOCTOBER, 1986

Hello again dear readers! We are getting intosomething new this month. Among the neatthings in the UNIX system is a text editor thatmakes it much quicker and easier for me towrite this, and a dandy and very fast spellingprogram that should remove many of my spell-ing blunders. However, we still need to add alaser jet printer to the system to get really highquality printing – you will have to put up withthe system’s thermal printer until we can af-ford to add the laser jet printer. Then, we willbe able to do typeset quality on everything.

It has come to my attention that we need toupdate the Harman-Kardon T-60 power sup-ply project in the December, 1985 issue, be-cause some of the power supply boards in theT-60 do not have numbered pins and thus ourinstructions referring to numbered pins aredifficult to follow.

Audio Basics Complete 1986 Back Issue Set Page 27

So, refer to the December, 1985 issue of AudioBasics, and make the following changes if, andonly if, you are rebuilding a T-60 that does nothave numbered pins on the power supply board:

Page 5, instruction referring to Pins 6 and 9:Unsolder the secondary power transformerleads (both blue) from the power supply board.

Page 5, instruction referring to Pins 7 and 8:Unsolder and remove the two white wires atthe power supply board (the small black switchis located on the main casting near the tonearm) and leave the switch in place. It, and thetwo white wires, will be re-used.

Page 5, instruction referring to Pin 14: Installan insulated wire from the AC pin with theshield side of the new shielded cable to the pinin the gray block closest to the side of thechassis. A black wire to the main control boardis already connected here.

Page 6, instruction referring to Pin 10: Connectone white switch wire to the AC pin with theshielded cable center conductor. Connect theother white switch wire to the fourth pin fromthe edge of the chassis in the gray block.Another white wire to the main control boardis already connected here.

Note: When you have completed the powersupply board work on a T-60 with a boardhaving unnumbered pins, there will be nowires connected to the second gray block hav-ing five pins.

All other December, 1985 instructions applyas written then. H-K changed the power supplyboard layout and we did not know it. If indoubt, call us before starting work. It is betterto not do the project than to do it wrong.

Now, I would like to talk a bit about “TIP-TOES” – those “spikes” that many recom-mend that you attach to the bottom of yourequipment to firmly locate the equipment onthe shelf or floor which are supposed to im-prove the sound quality. Well, maybe!

Essentially these “spikes” firmly couple theequipment to the shelf or floor it is sitting on.This may, or may not, help the sonic quality ofthe system depending upon the equipment be-ing coupled, and depending upon the characterof the shelf or floor. You need to know what isreally going on to understand if the Tip-Toeshave changed the sound for better, or for worse(and for worse will happen in many instances).

Things to understand first:

Most electronic equipment is microphonicto some extent. This means that vibrationsfed into the equipment will “rattle” theinternal parts, and produce an output thatwas not at the audio inputs. Worst caseexamples include vacuum tubes and largefilm capacitors. Obviously too, turntables

and CD players can mistrack if exposed tosevere external vibrations. Solid stateequipment is microphonic too, especiallyif poorly laid out, but to a much lesserdegree.

Most electronic equipment is supplied withsoft rubber feet of some type that to agreater or lesser degree, isolates theequipment from the vibrations around it.

The equipment is setting on “something,”and that something may, or may not, inand of itself, be solid and resistant toexternal vibrations, or be more like a “peachcrate” and be very sensitive to externalvibrations.

So let’s look at the situation now a little morecarefully, as it now becomes obvious that youmay have several different iterations of equip-ment, original isolating feet, and support struc-ture. Your equipment may be very subject tovibrations, or very resistant to vibrations. Itsoriginal feet may isolate it from vibrationsvery well, or very poorly. And the shelf orsupport the equipment is sitting on may be veryresistant to vibrations, or may be very subjectto vibrations. In your own system, each possi-bility is likely to be somewhere between theextremes, and the designer of the equipment,and the supplier of “spiked feet” did not knowwhat your particular combination was.

In an ideal situation, we would want equip-ment absolutely immune from vibrations, builtwith infinite mass buried in concrete and leadso that no external vibrations (even from anearthquake) would reach it at all. This is notvery practical to attempt (although my sandfilled concrete turntable base comes prettyclose – you can kick the base while the turn-table is playing without anything bad happen-ing).

If we change the feet on the equipment to“spikes” what we are really doing is removingthe original isolation from the shelf, and in-stead coupling the equipment hard into theshelf.

If the original feet did a good job of isolatingthe equipment from vibrations, and the shelf orsupport itself is “shaky” and is picking up lotsof vibrations, then, the hard coupling willintroduce more vibrations (from the shelf) intothe equipment, and the sonic results will beworse than with the original rubber feet.

If the shelf or support is rock solid (like mysand filled concrete turntable base) then hardcoupling with spiked feet will probably givepositive results (or make no difference at all).If the original equipment was absolutely im-mune from external vibrations internally, then,who cares what it is sitting on or how it iscoupled.

Obviously, combinations “in between” withslightly “shaky” shelves or supports, andslightly microphonic equipment will give ran-dom results. Usually, switching to spiked feetwill change the sound, but the change will mostlikely be simply a change, not a better, as youare substituting vibrations coupled into theequipment from the support for vibrations in-troduced directly into the equipment.

Note that “magic bricks” change the sound ofequipment too, but not by performing anymystical changes to magnetic fields. They sim-ply add mass to the system, making the equip-ment more isolated from external vibrations,and compress the feet (because of the addedmass) coupling the equipment harder into theshelf, which may, or may not, cause the equip-ment to pick up more, or less vibrations fromthe shelf.

In general, highly microphonic vacuum tubeequipment will exhibit major differences insonic quality (for better or worse) when spikedfeet or magic bricks are used. Well designedsolid state equipment will exhibit little or nochange at all.

Our recommendations: Try and locate yourequipment where it is subject to as little exter-nal vibrations as possible (out of “direct line offire” from the loudspeakers, for example). Makeyour support structure as massive, solid, andvibration resistant as practically possible. Then,go ahead and play with “Tip-Toes” if you want(they are not very expensive) to see if hardcoupling the equipment into vibration freesupports gives you sonic results you like bet-ter. Also try the other extreme – “sorbothane”isolation feet (available from Audioquest).These will help isolate the equipment from theshelf and tend to damp out vibrations inducedinto the equipment. Depending upon your sys-tem conditions, they may be more useful thantying the equipment hard into the shelf withTip-Toes.

Using Tip-Toes on loudspeakers presents otherconstraints.

If the loudspeaker is setting on soft carpet andis wobbling around, then spiked feet cuttingthrough to the firmer flooring beneath may bequite useful, depending on the structure of thefloor.

Essentially, Newton told us long ago that forevery action, there is an opposite and equalreaction. Thus, the energy dumped into yourloudspeaker voice coils that move the cone (orpanel in planar speakers) in one direction, triesto move the entire speaker system in the oppo-site direction. In other words, if the speakersystem is not massive and firmly “tied down”then a lot of music energy is wasted and losttrying to shake the speaker system around.

Audio Basics Complete 1986 Back Issue Set Page 28

Thus, Tip-Toes may be very useful if theyfirmly tie the loudspeaker system to a verysolid and inert floor structure instead of lettingit wobble around on the carpet.

However, if the floor is not really stiff (a woodupper floor or over crawl space, for example)then bad things may happen. You may end upfirmly affixing the loudspeaker to a giant sound-ing board – the “flexible” floor itself. Then,you may end up introducing a nice fat “boom”to your sound. Spiked feet on loudspeakersmay, or may not, be of value, again, dependingupon your room conditions.

We suggest you try this alternative if you havelow mass loudspeakers located on carpet – seta very heavy weight on top of the loudspeaker(a concrete patio block is fine for a startingexperiment). You may want to insert the blockinto a vinyl “slip cover” to prevent scratchingthings. This will increase the reaction mass(and give you obviously clearer and moredynamic sound) without hard coupling thespeaker system into the floor and adding“sounding board boom.”

Now, I would like to tell you about anotherinteresting and valuable audio product we re-cently evaluated, the Sony EV-S700U 8mmvideo recorder. Not only is this a very good andfunctional high resolution video recorder, butit is also a very high quality digital stereo audiorecorder with some very interesting capabili-ties.

Unlike the Kodak 8mm video deck we wereunderwhelmed with when reported on herein,the Sony top of the line 8mm video deck doeshave record level controls and meters. Thus,the dynamic range destroying automatic recordlevel circuits can be bypassed. You can set therecord levels yourself and make truly highfidelity audio recordings.

A subjective sonic evaluation tells us the Sony8 bit 30 kHz sampling rate system is certainlynot as good as our separate Sony PCM501ES16 bit 50 kHz system. But, it is a hell of a lotbetter than any analog audio cassette recorderI have ever heard, at any price, and you can gettwelve hours of stereo audio on one little 8mmcassette! I would judge its sonic quality to beequal to Beta Hi-Fi or perhaps a bit better. It iscertainly good enough to record vinyl recordswith no obvious loss, but it does show some“grain” and “compression” (especially somebass compression) that is obvious, but notsevere, as compared to the direct playbackfrom the Transcendence CD player or fromPCM501ES digital tapes. Sony is planning anautomobile deck using this format, and thatwill allow you to make better tape recordingsfor your car than ever before, and with thepossibility of twenty four hours of music onone tape (in the slow speed) it will make your

car source material really easy to carry around,and will make a car CD player redundant.

Since the market price of this unit is lower thanthat of “high end” audio cassette players (about$850.00 right now) and since it is a fine videorecorder too, it is a really useful “tool” toenhance the usefulness of your audio system.Remember, you can use it with the SonyPCM501 ES 16 bit digital audio processor too,for higher resolution stereo audio, just like anyother video tape recorder (with a two hour pertape time limitation). If you are shopping for avideo recorder, or for a high quality audiorecorder, we strongly urge you to consider theSony 8mm EV-S700U deck.

I want to inform you of one more option younow have in ordering a preamplifier from us, orwhen having your preamplifier rebuilt – a“delete phono circuits” option. Now that CD issimply “winning” in sonic quality compared tophonograph records (it is no contest), there isno good reason to force you to pay for a phonopreamplifier circuit you may never use. Thus,we now offer a delete phono circuit option onour preamplifiers. This reduces the price onTranscendence preamplifiers by $100.00, orreduces the price on Super Fet and Super Paspreamplifiers by $50.00. The old phono inputswill be wired up as additional line level inputs.Next month, a very worthwhile “budget” DynaPAT-4 do-it-yourself rebuild project is com-ing.

Frank Van Alstine

VOLUME FIVE NUMBER ELEVENNOVEMBER, 1986

We have, as promised, a major constructionproject for you this month – a significant up-grade to the performance of the Dynaco PAT-4 solid state preamplifier. There are severalother things to call to your attention beforestarting the project.

First of all, it is time to start thinking aboutrenewing your Audio Basics subscription again.Look at the date code on your mailing label. Ittells you the date of the last issue you have paidfor. Please help us by getting your renewal inearly so we don’t get buried in paperwork justin time for Christmas. The renewal price for1987 will remain at $16.00 for the year ($20.00for foreign air mail subscriptions). We alreadyhave all kinds of interesting topics ready to gofor the 1987 issues. You won’t want to missthem. Thanks for your kind support. Note thatmany have used Audio Basics as a useful andlow priced Christmas present for a friend. Mywife even includes a Christmas Card for therecipient of your gift at no extra charge.

Note also that we need your feedback. Pleasewrite or call us regarding topics you would liketo have covered in detail in Audio Basics. Skim

your back issues first, however, to make surewe have not already covered what you areinterested in. Again, I would be happy to evalu-ate any Compact Discs you think everybodyshould know about, and I certainly want to beinformed about interesting audio equipment.We cannot write about it if we don’t knowabout it. Your advice and help are welcomed.

A good friend of mine, Barney Feingold, 8Bittersweet Road, Fairport, New York 14450,wrote a very interesting booklet a few yearsago called, HOW TO BEAT THE HI FI RIP-OFF. It is very interesting reading and is espe-cially useful for those just starting out in audio.It is just as valuable now as when written in theearly 1980’s. Barney still has a few copiesavailable at $5.00 each. I suggest that you writeto him and order a copy before they are allgone.

I need to call to your attention a MAGNAVOXCD PLAYER model that we CANNOT USE inbuilding the Transcendence CD Player – themore expensive CDB650 model. This is thefirst generation of the 16 bit times fouroversampling machine, with additional “sizzle”added called Favorite Track Programing. Ithas several problems.

1. The additional memory, logic circuits, andpower supply circuit, for the favorite trackprograming circuits “gobble up” the chassisspace we need for our Transcendencecircuit board set (five new boards). Thus,there is no place to add our circuits.

2. The transport and load program in theCDB650 are from earlier generationmachines, and are not as sophisticated noras reliable as that in the newer CDB460(although we expect new productionCDB650 machines to be improved asPhilips runs out of older transports andboard sets).

3. The additional output filtering in theCDB650 is simply more of the same – twomore stages of the same tired old Op-Ampfilters that we already know don’t workwell. Adding two more bad filter stagessimply makes the linearity (and the sonicresults) worse. As we have mentionedbefore, the filters, and their drivers, mustbe replaced, not added onto, as everybodyelse is doing. Circuits added after thedamage has been done do not buy youbetter sound at all, only different sound.

We are now standardizing on the most currentand sophisticated Philips design, the 16 bittimes four oversampling CDB460 model forbuilding the Transcendence CD Player. Ithandles a wider variety of “out of spec” CDswell, and has a digital output port (that couldnot be done with the previous 14 bit models).Of course we can continue to install our cir-

Audio Basics Complete 1986 Back Issue Set Page 29

cuits in the 2041 model, if you already ownone, with excellent results. But we get a better“yield” with the CDB460 and so have stan-dardized on it for new production, and that isthe machine you should buy if you are lookingjust for a stock CD player. It is probably thebest stock machine on the open market and ispriced at under $200.00 in discount catalogs.

Now we have an easy and interesting con-struction project for you – a major upgradeof the Dyna PAT-4 preamplifier. Althoughthis is not our Super-Fet circuit set (the projectis an upgrade of the existing circuits) it willgive you a very impressive improvement indynamics, definition, clarity, and refinementand make your tired old PAT-4 at least as niceas anything new you can find in the $300 - $500price range (except for the even better Super-Fet and Transcendence all new internal cir-cuits).

This project will not repair a defective pream-plifier (unless only your existing power supplycapacitor is defective). It is not a cure forbroken hardware. You must start with a PAT-4 that is in working order. Note that StereoCost Cutters, Box 551, Dublin, Ohio 43017,has many original Dyna replacement parts (wedo not). Write them for their Dyna parts cata-log if you need to replace controls, jacks,switches, etc., before starting this project.

As always, we cannot guarantee your work-manship. The results you get are totally depen-dent upon your ability to follow directions andto do neat and reliable solder work. If in doubt– don’t do it!

Before starting the project, we advise you tocheck the following inside your preamp (withit unplugged from the AC power line of course):

Check the .02 microfarad 1000 volt capacitoron the power switch and replace it if it showssigns of overheating or burning.

Check the U Brackets holding the main PCCards. They should be attached to the compo-nent sides of the PC cards, not the foil sides. If

the brackets are improperly installed, they canshort out the circuits.

Check the condition of the four AC outlets onthe back panel. It is not unusual to find brokenones, which can cause electrical hazards. Re-place any broken AC outlets and make sure theAC wiring is safe.

Clean all controls, switches, and jacks with ahigh quality contact cleaner such as CramolinRed. Spray into each control and then operatethe control several times to clean the oxidationaway. Note that we can supply you withCramolin Red spray cans for $18.00 each (in-cluding shipping in the continental U.S.A.) butallow 4-6 weeks for delivery depending on ourstock.

Firmly tighten all hardware in the PAT-4,including the nuts and bolts holding the jacksets on, to insure good ground contacts andreliable future operation.

O.K. then, you have got a cleaned, tightened,and basically working PAT-4 preamp. Nowlet’s make it a lot better.

PARTS REQUIRED:

2 3300 MICROFARAD 80 VOLT ELECTRO-LYTIC CAPACITORS

1 6800 MICROFARAD 25 VOLT ELECTRO-LYTIC CAPACITOR

4 220 MICROFARAD 16 VOLT TANTA-LUM CAPACITORS

2 10 MICROFARAD 16 VOLT TANTALUMCAPACITORS

6 10 MICROFARAD 100 VOLT FILM CA-PACITORS

2 1 MICROFARAD 50 VOLT FILM CA-PACITORS

1 3300 OHM 1/4 WATT 5% TOLERANCERESISTOR

1 THUMBSCREW PHONO GROUNDHARDWARE SET

Note that we can supply you these parts as acomplete set for $60.00 including shipping inthe continental U.S.A. (tantalum and largefilm capacitors are expensive!)

We are going to break this project into fourparts, each of which can be completed, inorder, and evaluated before proceeding. Weurge you to do the work in the order suggested,and to try out and test the preamp at the comple-tion of each section. This will greatly help you“troubleshoot” problems as you will knowthey can only be with the section you justcompleted. If you do it all at once, then you willhave a hard time locating problems.

STAGE ONE (OPTIONAL, BUT VERYSTRONGLY RECOMMENDED) TONECONTROL DEFEAT.

The tone control circuits in the PAT-4 do notwork very well. The action of the control potscreates an excessive boost and cut with only asmall rotation of the controls. Flat response isnearly impossible to achieve unless you haveaccess to a square wave generator and dualtrace oscilloscope. You must set the controlknobs on the shafts so that when they pointstraight up, they are really flat and out ofcircuit, not “almost flat.” If the tone controlsare turned on even a little bit, the channelbalance and frequency response will be “allover the place” and good imaging and balancewill be impossible to achieve. Almost always,a PAT-4 will sound, and perform, better, withthe tone controls permanently out of circuit,and this is really easy to do.

Note also that the later stages of this project aremuch easier to do if the tone control circuits aredefeated, because many wires will be elimi-nated that get in your way doing the circuitboard upgrades. Note also that the later stagesof this project will improve the bass and treblelinearity so much that you won’t miss the tonecontrols – they are a “crutch” for “brokencircuits.”

Audio Basics Complete 1986 Back Issue Set Page 30

1. Locate, unsolder, and remove the twelvewires from Eyelets 13, 14, 15, 16, 17, and18 of each audio board running to the dualbass and dual treble controls.

2. Solder jumper wires across the top of eachcircuit board shorting together Eyelets 13,14, and 15 (one wire per board).

3. That is all there is to this stage, except tolisten to the preamp to make sure it stillworks. You now probably have flatresponse for the first time ever, and shouldnotice a much better balance to the sound.

STAGE TWO, JUMPING OUT FOUR EX-ISTING CAPACITORS.

There are four 1 microfarad electrolytic ca-pacitors in the signal path that must be elimi-nated (replaced with jumper wires) for best

sonic results. Two are easy to reach, two arevery difficult to reach.

1. Locate the two 1 microfarad capacitors(grey or black little “firecracker” shapedparts) on the back panel of the PAT-4.They are located between a 2 lug terminalstrip and the Tape Out jacks. Remove eachand replace with a jumper wire. Thesewere the easy ones, now for the hard ones!

2. Locate the two identical 1 microfaradcapacitors on the front panel of the preamp.They run between the front panel InputJack and the Tape Monitor switch (buriedbelow the vol-bal controls in front of thePC cards). Remove each of these andreplace with wires in the same locations(lots of luck).

NOTE: Some of you might want to remove thePC cards completely to access the parts men-

tioned above. If you do, first make a very goodsketch of where the wiring goes back in, and,first do the next section, the power supplyupgrade. If you are going to remove the cards,then wait until we describe the PC card workitself to do that, and then you can access thetwo front panel 1 microfarad capacitors at thesame time without having to remove and rein-stall the cards twice.

Now is the time to try the preamp again, beforestarting on the “meat” of the project.

STAGE THREE, INSTALLING AN UP-GRADED POWER SUPPLY.

A significant “weak link” in the PAT-4 is thepower supply capacitor – the “silver can” lo-cated in front of the power transformer. First ofall, it is probably so old that it is now defective– causing excess hum and “soggy” perfor-mance. Second, even when this capacitor isworking, it is inadequate. There is substantialaudio signal carried on the power supply feeds,generating unwanted feedback loops andcrosstalk, and there is not enough energy avail-able for good dynamics and bass performance.So, we shall replace the power supply capaci-tor with three separate capacitors that willmake the power supply many times strongerthan new and give you obviously cleaner andsolider sound. You will need the two 3300microfarad 80 volt capacitors and the 6800microfarad 25 volt capacitors, and the new 300ohm resistor to execute this stage.

1. Cut the wires to all lugs of the originalpower supply capacitor very close to thelugs (the wires will all be re-used). Savethe 220 ohm 3 watt resistor for later re-use,with as long a leads as possible. Removethe capacitor (and its bracket) from thechassis.

2. Refer to our sketch of the Power SupplyUpgrade. Using a bit of double-backedfoam tape, fasten the three new capacitorstogether in a triangular arrangement asshown, with the ground (-) leads pointingtowards each other (inward).

3. Solder a wire connecting the ground (-)leads of all three capacitors.

4. Connect the 220 ohm 3 watt resistor(salvaged from before) from the plus (+)lead of one 3300 microfarad 80 voltcapacitor to the plus (+) lead of the other3300 microfarad capacitor. Solder.

5. Connect the new 3300 ohm 1/4 watt resistorfrom the plus lead of one 3300 microfaradcapacitor to the plus lead of the 6800microfarad capacitor as shown in oursketch. Solder.

6. Make a “trial fit” of this array in the PAT-4 chassis in the same area where the originalcapacitor was located. You will be

Audio Basics Complete 1986 Back Issue Set Page 31

installing this array with double backedfoam tape and you will need more than onethickness of tape in some areas to make upfor the “bump” inside the chassis whereone previous mounting screw was located.

7. When you have got a good fit, firmly affixthe three capacitor array in the chassis asshown in our sketch. If you have a verydirty chassis, you may want to “degrease”it first with lighter fluid or similar so thatthe tape will stick firmly.

8. Now wire in the new power supply arrayas shown in the sketch.

Note that the four black wires from the PCcards go to ground.

Note that the Red/Yellow transformer leadgoes to ground.

Note that the Red wire from the diodebridge goes to “+ 50 Volts.”

Note that the Red wires from each Eyelet12 go to “+ 35 Volts.”

Note that the Red wires from each Eyelet4 go to “+ 17 Volts.”

9. It is possible that your 1/10 ampere slowblow fuse may fail at turn-on due to theextra current required to first charge thebigger new capacitors. You may replacethis fuse with a 1/4 ampere rated slowblow fuse. If this blows, you definitelyhave a wiring error.

10. You can now try the preamplifier again. Ifyou have a voltmeter, you should measureabout +50 volts, +35 volts, and +17 voltsat the power supply capacitors, keeping inmind that the voltages will come up slowly.It may take several minutes for the 6800microfarad capacitor to fully charge thefirst time the preamp is used. Avoid“shorting out” these capacitors. You willmake very large sparks and bangs!

When you play the preamp, you should noticemuch clearer and more dynamic sound, withbetter power. You will also notice that thepreamp turns on slower and turns off slowerthan before, with less stress. You should alsonotice a substantial reduction in “hum,” espe-cially on phono. If not, you have made a wiringerror.

STAGE FOUR, UPGRADING THE TWOAUDIO CIRCUIT BOARDS.

Finally, we will complete this project by re-placing fourteen capacitors on the audio cir-cuit boards. Replacing these capacitors willresolve several problems at the same time:

1. All parts to be replaced are old electrolyticpolarized capacitors, now likely to bedefective. They are apt to be leaky,allowing DC to appear on the controls and

switches, causing switching pops andcontrol noise. They are apt to be runningout of high frequency response, causingscrunched musical response. They are aptto have drifted in value, throwing off polepoints and causing the two channels tomistrack. The DC leakage and value driftalso screws up the biasing of the semi-conductors and causes the circuits toincrease in distortion.

2. Even if they were new and workingproperly, these electrolytic capacitors arestill not suitable for their circuitapplications. Their internal self resonantfrequency is in the 30,000 Hz range, closeenough to audio frequencies to causeinternal ringing and distortion to occur ontransients. They will be replaced withcapacitors with engineering characteristicsmuch more suitable for the applicationsneeded.

Refer to the sketch of the circuit board (bothboards are identical).

We will be replacing C1, C3, C4, C13, C15,C16, and C21 on each circuit board. It ispossible to replace the parts without removingthe PC boards from the chassis, if you arecareful. It is easier to do if you remove theboards. If you remove the boards, you mustfirst make a wiring diagram sketch so that youcan get all connections back to the boards doneproperly. If you do decide to remove the boards,now is the time to replace the two 1 microfaradcapacitors at the front panel input jack withjumper wires.

It is necessary to heat each solder connectionand gently lift the lead without lifting or tear-ing the circuit foil paths (which will be re-used). You can open the holes for new compo-nent leads with a round wood toothpick pushedthrough the hole from the foil side while heat-ing the pad with your solder pencil. We willstart with the hardest parts to reach first so youcan decide whether or not to remove the boardsfrom the chassis right away.

1. Remove C21 (50 microfarad 25 voltelectrolytic) from each circuit board andreplace each with a 10 microfarad 100 voltfilm capacitor (106). The film capacitorsare not polarized and it does not matterwhich way they go in the circuit.

2. Remove C15 (250 microfarad 6 voltelectrolytic) from each circuit board andreplace each with a 220 microfaradtantalum capacitor. Note that these newtantalum capacitors are polarized and thatthe (+) lead, the end with “silver blob”must point down towards the bottom of thePC card. We cannot use a film capacitor inthis application because there simply arenot any made of this needed high

capacitance value that would fit in thechassis.

3. Remove C16 (50 microfarad 25 voltelectrolytic) from each circuit board andreplace each with a 10 microfarad 100 voltfilm capacitor.

4. Remove C13 (5 microfarad 15 voltelectrolytic) from each circuit board andreplace each with a 1 microfarad 50 voltfilm capacitor (105).

5. Remove C3 (100 microfarad 6 voltelectrolytic) from each circuit board andreplace each with a 220 microfaradtantalum capacitor. Again the (+) end ofthe new tantalum capacitor must pointdown towards the bottom of the circuitboard.

6. Remove C4 (50 microfarad 25 voltelectrolytic) from each circuit board andreplace each with a 10 microfarad 100 voltfilm capacitor.

7. Remove C1 (5 microfarad 15 voltelectrolytic) from each circuit board andreplace each with a 10 microfarad tantalumcapacitor. Note that these new tantalumcapacitors are polarized – the long lead isthe + lead, and that the (+) lead must pointdown towards the bottom of the PC card.Although it looks like this might be a goodapplication for a smaller value filmcapacitor, it cannot be done because thesephono input capacitors are part of thephono feedback loop and making thecapacitor value smaller screws up the loopoperation and actually creates a large bassboom and unstable low frequencyoperation.

Congratulations, you have finished the PCcard work. Now resolder every connection inthe preamplifier. In particular, pay attention tothe wires connected to the PC cards. In manypoorly built kits, the leads are soldered to therivets at the eyelets only, without flowing thesolder to the actual foil paths. This causesintermittent operation. Make sure all wires aresmoothly flow soldered solidly to the foil traces.

The final step is to install the ThumbscrewGround terminal. Remove the original goldsheet metal ground screw. Drill out the hole sothat a #6 32 screw will clear from pointing outfrom the inside of the chassis. Firmly tighten a#6 32 kep nut from the outside. Screw on a #632 thumb nut onto the protruding screw andyou now have a much more convenient to usephono ground.

You now own a first class preamplifier withmuch smoother, clearer, and more musicalperformance than before. Enjoy it.

Frank Van Alstine

Audio Basics Complete 1986 Back Issue Set Page 32

VOLUME FIVE NUMBER TWELVEDECEMBER, 1986

Here we are at the end of five years of AudioBasics and still going strong. I never wouldhave thought that there was so much to writeabout when I started this back in late 1981. Iwould have thought that the major and under-ground publications would have improved sincethen, becoming more objective, having a clearermethodology towards finding the “truth” aboutaudio, and making my writing redundant. In-stead, we now find the underground maga-zines emulating the major audio publications,accepting manufacturer’s advertising, and thusbecoming exactly the opposite of what theyclaimed was their only real reason for exist-ence – an alternative from advertiser supported(and for all practical purposes, written) equip-ment reviews and audio data. We are findingthe major magazines drifting in the oppositedirection – towards subjective reviews withsonic virtues unsupported by any observable,verifiable, and repeatable engineering data.Nobody seems to want to learn, to gain knowl-edge, data, and to correlate facts and improvethe state of the engineering of audio. Every-body seems only to want to speculate, to haveopinions, and to have feelings, wants, andwishes about audio.

Unfortunately, the wishes and wants, the feel-ings and opinions, and the desires and needsdon’t get the job done. One gets better resultsby doing a better job. One gets closer to realityby more carefully observing and correlatingthe data, and by being willing to learn moreabout the subject, even when the learning pro-cess is difficult and the “facts” don’t turn out tobe what you really wanted them to be.

So – we will keep going with Audio Basics fora few more years – until the bigger publica-tions show signs of giving you that real datayou deserve to know, and for as long as yousupport me with your kind comments andrenewals. Thanks for your kind interest in us.We would really appreciate having you with usfor another year. However, if you are going to“go away,” please let us know why. We cannotdo “what you want” if you never tell us whatyou want.

A thought rergarding last month's Pat-4 up-grade project – we are running out of thetantalum capacitors and when we are out wewill not be able to supply the parts kit. Thedemand for this kit is running much heavierthan we expected and our remaining stock of220 and 10 microfarad tantalum capacitors isrunning low. These are very expensive partsthat we do not plan on restocking as we don’tuse them any place in our own internal produc-tion. We can only do 15 - 20 more kits and willneed to supply good recycled tantalums to fillout those. Order soon to avoid disappointment.

Note that we did get two letters complainingthat we wrote the PAT-4 project, wonderingwhy we wasted their time and Audio Basic’sspace. We also got about 30 parts kit orders,and calls from more of you doing the project onyour own. We cannot please everybody all thetime, but the PAT-4 rebuild sure seems to havepleased a lot more people than it has upset.

We have received several calls and letters frompeople confused about our comments regard-ing the Magnavox CDB650 CD player, espe-cially from people who have noticed the excel-lent Stereo Review evaluation of the CDB650and from those who have used the CDB650themselves with outstanding results.

To clarify – yes, the CDB650 is a fine CDplayer and the 16 bit times four oversamplingtechnology it uses is superior in every respectto the older 14 bit times four technology, and tothe oriental 16 bit brick wall analog filtermachines and the only slightly better 16 bittimes two machines. Yes indeed, compared towhat else they have seen, the MagnavoxCDB650 probably is the best CD player StereoReview has seen, so far!

HOWEVER, THE CDB650 is the “first gen-eration” of Magnavox 16 bit times fouroversampling CD players. THE CDB460 IS ANEWER “SECOND GENERATION” MA-CHINE AND IS BETTER YET:

THE CDB460 HAS A BETTER LOADPROGRAM THAT HANDLES MORE“OUT OF SPEC” DISCS FASTER.

THE CDB460 HAS A NEWER,IMPROVED TRANSPORT DESIGNWITH USEFUL STRUCTURALREINFORCEMENT.

THE CDB460 HAS MANY DETAILIMPROVEMENTS TO THE LOGICBOARD.

THE CDB460 HAS ROOM FOR OURADDITIONAL FIVE PC CARDTRANSCENDENCE CIRCUIT SET.THE CDB650 DOES NOT HAVE ROOMFOR OUR CIRCUITS.

THE CDB460 IS MUCH LESSEXPENSIVE. If you cannot find a stockCDB460 in your area, and you might notbecause it is a brand new model, we willsell you a stock CDB460 that has gonethrough and passed our incominginspection for $250.00 including shippingto you in the continental USA.

I KEEP HEARING FROM PEOPLEWHO SAY THEY HAVE PURCHASEDA CDB650 BASED UPON OURRECOMMENDATIONS AND NOWWANT US TO REBUILD IT. WE HAVENEVER AND DO NOT NOWRECOMMEND THE CDB650. WE

RECOMMEND AND USE THE CDB460.Please re-read our comments in the 11-86and 12-86 issues.

And, for those of you who write to wonder“how can your Transcendence circuits in theCDB460 possible sound any better at all thana stock Magnavox CDB650?” rest assured thatour circuits can, and do sound better. Perhapssome of you that already have a TranscendenceCD player should write me a note we canpublish herein in the next month or so toconvince those that doubt we are telling thetruth.

We did get some interesting feedback from oneof my Chicago field rep’s customers. Afterauditioning the Transcendence CD Player, hedid purchase one from Gregg McArthur. How-ever, he had reservations, and told Gregg,“Although this is the best CD player I haveheard, when I get it home my best LPs are stillgoing to outplay my best CDs.” A few dayslater Gregg heard from the client again, lettingGregg know that the Transcendence CD Playerwas working a bit better than expected. Greggwas informed that with the T CD Player, notonly did the client’s best CDs outperform hisbest LPs, but that even his worst CDs outper-formed his best records, and that all the CDproblems he previously thought he had, hadvanished!

Here are a few “last minute Christmas choices”somebody on your Christmas list might enjoy.The following is a listing of some CompactDiscs I like a lot and find myself playing againand again.

Nutcracker, Compete Ballet Score, TelarcCD80137 (two CD set). If you don’t have thiscomplete and lovely Nutcracker to play at thisholiday season, you are really missing some-thing lovely!

William Tell and Other Favorite Overtures,Telarc CD80116. Fun to “show off” your sys-tem with, even to those who don’t like “classi-cal music” (“Hi-ho, Silver!”).

B&W Presents the Academy of Ancient Music,Christopher Hogwood, BW001. An assort-ment of classical works played on authenticinstruments and recorded very, very well.Available at most B&W loudspeaker dealers.We have it for $15.00 including shipping in theUSA (allow 30 days for delivery).

Pachelbel: Kanon, and Tchaikovsky, Serenadefor Strings, Telarc CD80080. Simply beautifulstring sound, the way it should always be butrarely is.

Brahms: Ein Deutches Requiem, TelarcCD80092. Robert Shaw directing the AtlantaSymphony and Choir. Soft and spacious voicesblending so well with the orchestra.

Audio Basics Complete 1986 Back Issue Set Page 33

Berlioz: Symphonie Fantastique, TelarcCD80076. The last two movements separatethe real audio playback systems from the pre-tenders.

Cats: Complete Original Broadway Cast,Geffen 2031-2 (2 CD set). Although not asgood as our front row center seats at the realplay last summer in London, it actually iseasier to understand the words on the CD thanit was there live! This CD captures the energyand vitality of the live performance, but makesone wish for a high fidelity stereo video ver-sion too.

Warren Bernhardt Trio ‘83, DMP CD441. Stateof the art recording of cymbals – or – yousimply cannot do this on a vinyl record at all!Fine jazz trio performance throughout.

Billy Barber, Lighthouse, DMP CD455. Again,things done here you cannot do on records –jazz piano with some very unusual accompani-ment.

Linda Ronstadt, For Sentimental Reasons, Asy-lum 960474-2. The last CD Linda did withNelson Riddle before he died, and probably thebest.

Digital Dixieland, Verve VCD107. A veryinexpensive CD label with lots of fine Dixielandjazz, performed and recorded just fine.

West of Oz, Amanda McBroom, Sheffield CD-15. Just really fine vocal and instrumentalwork, very carefully recorded.

Tom Browne, Browne Sugar, GRP D9517.Although the front says “digital recording”and the program notes say “analog recording”it is a fine recording capturing the power, taste,and dynamics of the brass instruments.”

GRP Digital Sampler #2. GRP D9529. Thiswill give you a really good “sample” of thecapabilities of GRP. In this case, if you like thesample cut, you really will like the CD it camefrom (I have nearly all of them).

Denon Audio Technical CD, Denon 38C39-7147. You really ought to own this CD. It has99 tracks of technical data that can turn yourCD player into a very competent audio signalgenerator. It has white noise, sine waves, fre-quency sweeps, amplitude sweeps, phasesweeps, 20 Hz tones (actually 21.5 Hz), tran-sients, square waves, impulse signals, IM tests,just about everything you ever wanted, andmore. It makes it easy to set up, balance, adjust,and with a little too much enthusiasm, destroyyour system. If you cannot find it, call Denonand bug them for it. You need it.

Lets think about a couple of excellent sourcesfor low cost (how about free!) Compact Discs:

The first source should be obvious to you– your local public library. Many librariesare carrying Compact Discs now, available

for check out just like books andphonograph records. The Compact Discshave one very large advantage over loanerphonograph records – they have not beendestroyed by being played on a kiddierecord player and most likely, they havenot been passed around at a beach sidepizza party. Because Compact Disc is a“new” development, and not yet availableto the boombox crowd (hardly) the usersof CDs are more likely to be people at theleading edge of technology, and more likelyto take care of borrowed goods. In addition,its harder to damage a CD by playing it ona bad system. Note that distilled water(available at your local drug store) and Q-Tips make a good CD cleaner – gentlybrushed from in to out with a radial motion.I don’t trust any CD cleaning device orchemical cleaner yet.

If you live in the Boston area, you canrecord CDs onto your VCR that are beingbroadcast on UHF TV by a local publictelevision station. The catch is that you aregoing to need a digital audio processor(Sony PCM501ES or similar) to play backthe CDs you have recorded. The CDs arebeing converted to video data by the stationbefore transmission. What you record withyour VCR is identical to having the CD,CD Player, and Digital Audio Processor athome. All broadcast distortions “drop out”as the noise, bandwidth, distortion, anddynamic range limitations of broadcastsound simply are not part of the digitaldata. You actually get all of the CDcapability with no significant distortionsadded. Note that you should RECORDAND SAVE THE BROADCASTS NOWON YOUR VCR even if you don’t own aDigital Audio Processor yet. Check withyour local public television station and seeif they are planning this broadcast servicetoo. It would be a good reason to supportthem.

Now for some GOOD NEWS FOR DYNA St-400, St-410, AND St-416 OWNERS! We havefinally perfected a “budget priced” power mos-fet circuit set for your amplifiers – the brandnew MOS-FET 400C AMPLIFIER! Althoughour Transcendence 400 amplifier has long beenknown for its very high quality, it has unfortu-nately been known for its relatively high pricetoo – $1500.00 to install in your St-400 or St-416 chassis and not available at all in the St-410 chassis. The high price being caused by theneed to furnish and install 16 new power mos-fets, and the complete heatsink and faceplatemachine work necessary to do this projectproperly. Well, now we have something muchless expensive, and just as great sounding(within its current limits), the Mos-Fet 400Cfor just $650.00 installed in your 400, 416, or

410 including return shipping to you in thecontinental USA and our limited two yearparts and labor warranty.

Several things have happened to make theMos-Fet 400C possible.

The first good thing that has happened is thenew “large die” Hitachi power mos-fet deviceset, the 2SK176 and 2SJ56. These output mos-fets have 1.25 times the die area of the standard2SK135 and 2SJ50 devices, and for all practi-cal purposes, 8 of the new devices equal 10 ofthe standard devices. Thus, we can have safe200 watt per channel operation with just eightof these heavy duty mos-fets (as long as welimit operation to normal 8 ohm and 4 ohmloudspeakers – not for 1 ohm and 2 ohm ribbonspeakers). This means we do not have to ma-chine the heat sink for 16 power mos-fet out-puts, and the output wiring labor time is alsocut in half (and, we can use the 410 heatsinkassembly that was not usable at all for a 16mos-fet output circuit). An additional virtue ofthe new mos-fets is their lower bias currentrequirements. They need only 75 milliampereper device, instead of 100 milliampere as in thestandard mos-fets. In the 400 chassis, the totalcurrent is now 8 x 75 milliamps = .6 ampereinstead of 16 x 100 milliamps = 1.6 ampere.This substantially reduces the ripple on thepower supply (requires a less expensive powersupply) and reduces the heat output of theamplifier (no fan required).

Second, we can directly use the new Mos-Fet500C driver cards developed for the even morepowerful Hafler 500 chassis with no duplica-tion of engineering efforts. Except for a slightrebiasing for 75 volt instead of 90 volt opera-tion, everything done for the higher power,higher voltage DH-500 application works justfine, and provides even better safety margins,in the St-400, 416, 410 chassis.

Third, we rethought our power supply require-ments for this application, and have concen-trated on additional very stiff decoupled sup-ply sections for the driver boards. This isgiving us excellent stability, drive, and lownoise without significant cost and without caus-ing excess stress on the power switch. Theoriginal power switch handles the load withoutbreakdown, eliminating the need for expen-sive electronic switching operation.

Finally, we have limited our efforts to the allnew circuits only (no cosmetic improvements).The Mos-Fet 400C retains the original face-plate and controls (only the power switch andpilot lamp are functional). If your unit haspower meters or power leds, they will be sal-vaged and will function if they were receivedby us in working order. We do not have thefacilities or parts to repair those functions ifthey are defective.

Audio Basics Complete 1986 Back Issue Set Page 34

Thus, the Mos-Fet 400C is a complete newamplifier inside your Dyna chassis. You get anew power mos-fet output circuit, new groundplane output networks inside the heatsink, newaudio circuit cards of our design, and a newaudio power supply (independent sections foreach channel). All original circuit boards, tran-sistors, and wiring are thrown away. Obvi-ously, there will be no additional charge forrepairs, no matter how badly your amp isblown up. Note however that you must supplya complete unit with a good power transformerwith basic mechanical integrity. The way itlooks now is what you are going to have to lookat. The way it sounds now, who cares, you willget back one of the very best sounding ampli-fiers in existence.

Regarding the sound of the Mos-Fet 400C, it isjust a little bit different than our other products,a touch more “romantic.” If what you reallywant is a $6000 tube amplifier, you probablywill decide that our $650 mos-fet amplifiercircuits are better yet! It is the high poweredsolid state amplifier for folks who simply don’tlike high powered solid state amplifiers. Its gotgobs of guts and control, but it is sweet andspacious sounding too. Many will feel that thisis our most cost effective product and it isavailable right now.

Of course the more expensive Transcendence400 continues in production, especially forthose of you who need continuous 2 ohm drivecapability at very high power. But, for thosewith rational loudspeakers who want musicwith power and authority at a real world price,the Mos-Fet 400C is just for you.

I would like to talk a little now about anotheramplifier, a new SUPERPHON POWER AM-PLIFIER, that did not work well at all for us.

A client brought this unit in to compare withour Mos-Fet Series C amplifiers and we gaveit a good listen and a bench check too.

We listened to it first, and it sounded prettygood. It was smooth, clear, and without majorcolorations or annoyances. It did not havemuch “ommph” for its power and size (its 100watt per channel did not come close to a Mos-Fet 120C’s 60 watts per channel) but it didseem to work better than a similarly pricedAdcom GF555. I felt it might be a product weshould recommend, until we got it to the testbench!

The Superphon looked to be a simple, but wellbuilt bi-polar amplifier that easily made itspower rating and looked pretty stable, until wegot beyond simple resistive load testing andstarted observing how it behaved with a ca-pacitive load. Normally we start our capacitiveload testing with a really small capacitor, a .01microfarad 100 volt film capacitor in parallelwith our bench 200 watt non-inductive load

resistors. This is a capacitive load that any oldcrummy circuit should drive with no trouble atall, perhaps with a hint of leading edge over-shoot if the amp circuit was old fashioned. TheSuperphon didn’t generate a slight leadingedge rise on a .01 microfarad load in parallelwith 8 ohms, it WENT INTO FULL BOREOSCILLATION! And, not only did the chan-nel with this tiny capacitive load oscillate, butthe other channel, connected only to a resistiveload, went into total oscillation too. The oscil-lations existed even if the input signal wassimple sine waves for only a couple of wattsoutput at 1 kHz.

This is the worst capacitive load drive we haveyet seen on a “modern” amplifier. It shows thatthe Superphon will sound very different de-pending upon the loudspeakers (and speakercables) used, and suggests that the amplifiermay have future problems if its stability mar-gins decrease with age at all. A close examina-tion of the circuit showed that the designersthought they could get away without the use ofoutput inductors. They cannot! An output in-ductor simply decouples an amplifier from theworst effects of external capacitive loads, andare absolutely necessary with bi-polar outputstages to avoid the oscillations we see with theSuperphon. Needless to say, the client, afterhearing the difference and seeing the differ-ence on the scope, purchased a Mos-Fet 120Cinstead of the Superphon. And, needless to say,we cannot recommend the Superphon for youeven though it is pretty nice sounding on someloudspeakers (including many B&W models)because it may turn into a complete oscillatoron other speakers and destroy itself and yoursystem.

Enough for now. Have a happy Christmas andNew Year, and look for us again each monthnext year.

Frank Van Alstine