Ngun n p tuyn tnh

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Ni dung : Tng qut v mch ngun n p tuyn tnh c hi tip, Phn tch mch ngun n p tuyn tnh trong Ti vi en trng, trong Ti vi Ni a nht. 1. S khi ca mch n p c hi tip .

S khi ca mch n p c hi tip . * Mt s c im ca mch n p c hi tip :

Cung cp in p mt chiu u ra khng i trong hai trng hp in p u vo thay i hoc dng tiu th ca ti thay i , tuy nhin s thay i ny phi c gii hn. Cho in p mt chiu u ra c cht lng cao, gim thiu c hin tng gn xoay chiu.

* Nguyn tc hot ng ca mch.

Mch ly mu s theo di in p u ra thng qua mt cu phn p to ra ( Ulm : p ly mu) Mch to p chun => gim ly mt mc in p c nh (Uc : p chun ) Mch so snh s so snh hai in p ly mu Ulm v p chun Uc to thnh in p iu khin. Mch khuch i sa sai s khuch i p iu khin, sau a v iu chnh s hot ng ca n cng xut theo hng ngc li, nu in p ra tng => thng qua mch hi tip iu chnh => n cng xut dn gim =>in p ra gim xung . Ngc li nu in p ra gim => thng qua mch hi tip iu chnh => n cng xut li dn tng => v in p ra tng ln =>> kt qu in p u ra khng thay i.

2. Phn tch hot ng ca mch ngun c hi tip trong Ti vi en trng Samsung in p u vo cn gn xoay chiu in p u ra bng phng

Mch n p tuyn tnh trong Ti vi Samsung en trng . * ngha cc linh kin trn s .

T 2200F l t lc ngun chnh, lc in p sau chnh lu 18V , y cng l in p u vo ca mch n p, in p ny c th tng gim khong 15%. Q1 l n cng xut ngun cung cp dng in chnh cho ti , in p u ra ca mc n p ly t chn C n Q1 v c gi tr 12V c nh . R1 l tr phn dng c cng xut ln ghnh bt mt phn dng in i qua n cng xut. Cu phn p R5, VR1 v R6 to ra p ly mu a vo chn B n Q2 . Diode zener Dz v R4 to mt in p chun c nh so vi in p ra. Q2 l n so snh v khuych i in p sai lch => a v iu khin s hot ng ca n cng xut Q1. R3 lin lc gia Q1 v Q2, R2 phn p cho Q1

* Nguyn l hot ng .

in p u ra s c xu hng thay i khi in p u vo thay i, hoc dng tiu th thay i. Gi s : Khi in p vo tng => in p ra tng => in p chn E n Q2 tng

nhiu hn chn B ( do c Dz gim t chn E n Q2 ln Ura, cn Ulm ch ly mt phn Ura ) do UBE gim => n Q2 dn gim => n Q1 dn gim => in p ra gim xung. Tng t khi Uvo gim, thng qua mch iu chnh => ta li thu c Ura tng. Thi gian iu chnh ca vng hi tip rt nhanh khong vi giy v c cc t lc u ra loi b, khng lm nh hng n cht lng ca in p mt chiu => kt qu l in p u ra tng i phng. Khi iu chnh bin tr VR1 , in p ly mu thay i, dn n Q2 thay i , dn n Q1 thay i => kt qu l in p ra thay i, VR1 dng iu chnh in p ra theo mun .

3. Mch ngun Ti vi ni a nht.

S mch ngun n p tuyn tnh trong Ti vi mu ni a Nht .

C1 l t lc ngun chnh sau cu Diode chnh lu. C2 l t lc u ra ca mch ngun tuyn tnh. Cu phn p R4, VR1, R5 to ra in p ly mu ULM R2 v Dz to ra p chun Uc R3 lin lc gia Q3 v Q2, R1 nh thin cho n cng xut Q1 R6 l in tr phn dng, l in tr cng xut ln . Q3 l n so snh v khuch i p d sai Khuch i in p d sai Q1 n cng xut ngun => Ngun lm vic trong di in p vo c th thay i 10%, in p ra lun lun

c nh .

Mch n p c nh, IC n p

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Ni dung : Mch n p c nh dng Diode Zener, Mch n p dng Transistor khuych i, IC n p LA7805, LA7808, ng dng ca IC n p trong cc mch cp ngun. 1. Mch n p c nh dng Diode Zener.

Mch n p to p 33V c nh cung cp cho mch d knh trong Ti vi mu

T ngun 110V khng c nh thng qua in tr hn dng R1 v gim trn Dz 33V ly ra mt in p c nh cung cp cho mch d knh Khi thit k mt mch n p nh trn ta cn tnh ton in tr hn dng sao cho dng in ngc cc i qua Dz phi nh hn dng m Dz chu c, dng cc i qua Dz l khi dng qua R2 = 0 Nh s trn th dng cc i qua Dz bng st p trn R1 chia cho gi tr R1 , gi dng in ny l I1 ta c I1 = (110 - 33 ) / 7500 = 77 / 7500 ~ 10mA Thng thng ta nn dng ngc qua Dz 25 mA

2. Mch n p c nh dng Transistor, IC n p . Mch n p dng Diode Zener nh trn c u im l n gin nhng nhc im l cho dng in nh ( 20mA ) . c th to ra mt in p c nh nhng cho dng in mnh hn nhiu ln ngi ta mc thm Transistor khuych i v dng nh s di y.

Mch n p c Transistor khuych i

mch trn in p ti im A c th thay i v cn gn xoay chiu nhng in p ti im B khng thay i v tng i phng. Nguyn l n p : Thng qua in tr R1 v Dz gim c nh in p chn B ca Transistor Q1, gi s khi in p chn E n Q1 gim => khi in p UBE tng => dng qua n Q1 tng => lm in p chn E ca n tng , v ngc li ... Mch n p trn n gin v hiu qu nn c s dng rt rng di v ngi ta sn xut cc loi IC h LA78.. thay th cho mch n p trn, IC LA78.. c s mch nh phn mch c mu xanh ca s trn.

C n p h LA78..

IC n p LA7805

LA7805 LA7808 LA7809 LA7812

IC n p 5V IC n p 8V IC n p 9V IC n p 12V

Lu : H IC78.. ch cho dng tiu th khong 1A tr xung, khi rp IC trong mch th U in > Uout t 3 n 5V khi IC mi pht huy tc dng. 3. ng dng ca IC n p h 78.. IC n p h 78.. c dng rng ri trong cc b ngun , nh B ngun ca u VCD, trong Ti vi mu, trong my tnh v v...

ng dng ca IC n p LA7805 v LA7808 trong b ngun u VCD

Khi ngun nui0 Comment Size- Size+ 21/12/2009 Other... RSS

Ni dung : Nhim v ca khi cp ngun, s tng qut, mch chnh lu v mch lc, Mch n p tuyn tnh, Cc h hng thng gp ca khi cp ngun v phng php kim tra sa cha. 1. Khi ngun nui Nhim v ca khi cp ngun l cung cp ngun 1chiu 12V n nh cho my hot ng, in p vo l ngun xoay chiu 220V AC khng n nh.

S khi - khi ngun nui

Bin p c nhim v i in 220V AC xung in p 18V AC Mch chnh lu cu v lc chnh lu in p xoay chiu AC thnh in p mt chiu DC Mch n p tuyn tnh : c nhim v gi cho in p ra c nh v bng phng cung cp cho ti tiu th .

Mch gim p, chnh lu v mch lc .

Bin p v mch chnh lu cu, mch lc

Bin p ngun : in p vo = 220V 50Hz , in p ra = 18V D1, D2, D3, D4 l mch chnh lu cu , chnh lu in AC thnh DC T C1 : 2200F/25V l t lc ngun chnh

Bin p v mch chnh lu cu, mch lc trong thc t. Mch n p tuyn tnh : Nhim v : Mch n p tuyn tnh c nhim v => To ra in p u ra n nh v bng phng, khng ph thuc vo in p vo, khng ph thuc vo dng in tiu th S tng qut

S tng qut mch n p tuyn tnh

in p vo l ngun DC khng n nh v cn gn xoay chiu. in p ra l ngun DC n nh v bng phng Mch ly mu l ly ra mt phn in p u ra, in p ly mu tng gim t l vi in p u ra . Mch to p chun : l to ra mt in p c nh Mch d sai : so snh in p ly mu vi in p chun pht hin s bin i in p u ra v khuch i thnh in p iu khin quay li iu chnh m ca n cng xut, nu in p gim th p iu khin , Khin cho n cng xut dn mnh, v ngc li . n cng xut : khuch i v dng in v gi cho in p ra c nh .

S chi tit ca mch n p tuyn tnh my Samsung

Mch n p tuyn tnh trong Ti vi Samsung 359R

Mach to p ly mu gm R5, VR1, R6 , in p ly mu c a vo cc B n Q2 . Mch to p chun gm Dz v R4, in p chun a vo cc E n Q2 Q2 l n d sai , so snh hai in p ly mu v in p chun to ra in p iu khin a qua R3 iu khin hot ng ca n cng xut Q1 Q1 l n cng xut R1 l in tr phn dng T 2200F l t lc ngun chnh .

Nguyn tc n p nh sau : Gi s khi in p vo tng hoc dng tiu th gim => in p ra tng ln=> in p chun tng nhiu hn in p ly mu => lm cho in p UBE n Q2 gim => n Q2 dn gim => dng qua R3 gim => n Q1 dn gim ( v dng qua R3 l dng nh thin cho n Q1 ) => kt qu l in p ra gim xung, vng iu chnh ny din ra trong thi gian rt nhanh so vi thi gian bin thin ca in p, v vy in p ra c c tuyn gn nh bng phng. Trng hp in p ra gim th mch iu chnh theo chiu hng ngc li. 2. H hng thng gp ca khi cp ngun 1) Khng c in vo my, khng c ting, khng c mn sng.

My khng mn sng, khng hnh, khng vo in Nguyn nhn :

Chy bin p ngun, hoc t cu ch. Chy cc Diode ca mch chnh lu

Kim tra :

Kim tra bin p ngun : ng h thanh x1 v o vo hai u phch cm in AC, nu kim ng h khng ln => l bin p ngun b chy, nu kim ln vi chc ohm l bin p bnh thng. o kim tra trn cc Diode chnh lu cu Cui cng ta cp in v o trn hai u t lc ngun chnh phi c 18V DC

2) Hnh nh b un o, c ting loa .

Hnh nh b un o Nguyn nhn :

Bn cht ca hin tng trn l do in p cung cp cho my b nhim xoay chiu 50Hz v vy nguyn nhn l :

Hng t lc ngun chnh 2200F/25V Hng mt trong s cc Diode chnh lu cu Hng mch n p tuyn tnh

Kim tra :

Kim tra cu Diode, nu cu Diode bnh thng th o st p trn 4 Diode phi bng nhau, nu in p ny lch l c 1 hoc 2 trong s 4 Diode b hng o in p DC trn t lc ngun chnh phi c 18V DC, nu in p ny gim < 18V l t lc ngun b kh . Kim tra in p DC u ra ca ngun n p tuyn tnh c khong 11V => 12V, v iu chnh bin tr ngun (VR1) in p u ra phi thay i, nu in p ra qu cao khong 15V hoc qu thp khong 7V v iu chnh bin tr VR1 khng tc dng l hng mch n p tuyn tnh.

Tr ni tip, song song - ng dng ca R

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Ni dung: in tr mc ni tip, in tr mc song song, in tr mc hn hp, ng dng ca in tr trong mch in Trong thc t , khi ta cn mt in tr c tr s bt k ta khng th c c , v in tr ch c sn xut khong trn 100 loi c cc gi tr thng dng, do c mt in tr bt k ta phi u in tr song song hoc ni tip. 1. in tr mc ni tip .

in tr mc ni tip.

Cc in tr mc ni tip c gi tr tng ng bng tng cc in tr thnh phn cng li. Rtd = R1 + R2 + R3 Dng in chy qua cc in tr mc ni tip c gi tr bng nhau v bng I. I = ( U1 / R1) = ( U2 / R2) = ( U3 / R3 ) T cng thc trn ta thy rng , st p trn cc in tr mc ni tip t l thun vi

gi tr int tr . 2. in tr mc song song.

in tr mc song song

Cc in tr mc song song c gi tr tng ng Rtd c tnh bi cng thc. (1 / Rtd) = (1 / R1) + (1 / R2) + (1 / R3) Nu mch ch c 2 in tr song song th Rtd = R1.R2 / ( R1 + R2) Dng in chy qua cc in tr mc song song t l nghch vi gi tr in tr . I1 = ( U / R1) , I2 = ( U / R2) , I3 =( U / R3 ) in p trn cc in tr mc song song lun bng nhau

3. in tr mc hn hp

in tr mc hn hp.

Mc hn hp cc in tr to ra in tr ti u hn . V d: nu ta cn mt in tr 9K ta c th mc 2 in tr 15K song song sau mc ni tip vi in tr 1,5K .

4 . ng dng ca in tr : in tr c mt mi ni trong thit b in t v nh vy in tr l linh kin quan trng khng th thiu c , trong mch in , in tr c nhng tc dng sau :

Khng ch dng in qua ti cho ph hp, V d c mt bng n 9V, nhng ta ch c ngun 12V, ta c th u ni tip bng n vi in tr st p bt 3V trn in tr.

u ni tip vi bng n mt in tr. - Nh hnh trn ta c th tnh c tr s v cng xut ca in tr cho ph hp nh sau: Bng n c in p 9V v cng xut 2W vy dng tiu th l I = P / U = (2 / 9 ) = Ampe cng chnh l dng in i qua in tr. - V ngun l 12V, bng n 9V nn cn st p trn R l 3V vy ta suy ra in tr cn tm l R = U/ I = 3 / (2/9) = 27 / 2 = 13,5 - Cng xut tiu th trn in tr l : P = U.I = 3.(2/9) = 6/9 W v vy ta phi dng in tr c cng xut P > 6/9 W

Mc in tr thnh cu phn p c c mt in p theo mun t mt in p cho trc.

Cu phn p ly ra p U1 tu .

T ngun 12V trn thng qua cu phn p R1 v R2 ta ly ra in p U1, p U1 ph thuc vo gi tr hai in tr R1 v R2.theo cng thc . U1 / U = R1 / (R1 + R2) => U1 = U.R1(R1 + R2) Thay i gi tr R1 hoc R2 ta s thu c in p U1 theo mun.

Phn cc cho bng bn dn hot ng .

Tham gia vo cc mch to dao ng R C

Mch to dao ng s dng IC 555

Chnh lu in xoay chiu

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Ni dung: Tng qut v b ngun, Mch chnh lu bn chu k, Mch chnh lu c chu k. 1. B ngun trong cc mch in t . Trong cc mch in t ca cc thit b nh Radio -Cassette, mlpy, Ti vi mu, u VCD v v... chng s dng ngun mt chiu DC cc mc in p khc nhau, nhng ngoi zc cm ca cc thit b ny li cm trc tip vo ngun in AC 220V 50Hz , nh vy cc thit b in t cn c mt b phn chuyn i t ngun xoay chiu ra in p

mt chiu , cung cp cho cc mch trn, b phn chuyn i bao gm :

Bin p ngun : H th t 220V xung cc in p thp hn nh 6V, 9V, 12V, 24V v v ... Mch chnh lu : i in AC thnh DC. Mch lc Lc gn xoay chiu sau chnh lu cho ngun DC phng hn. Mch n p : Gi mt in p c nh cung cp cho ti tiu th

S tng qut ca mch cp ngun. 2. Mch chnh lu bn chu k . Mch chnh lu bn chu k s dng mt Diode mc ni tip vi ti tiu th, chu k dng => Diode c phn cc thun do c dng in i qua diode v i qua ti, chu k m , Diode b phn cc ngc do khng c dng qua ti.

Dng in p u ra ca mch chnh lu bn chu k. 2. Mch chnh lu c chu k Mch chnh lu c chu k thng dng 4 Diode mc theo hnh cu (cn gi l mch chnh lu cu) nh hnh di.

Mch chnh lu c chu k .

chu k dng ( u dy pha trn dng, pha di m) dng in i qua diode D1 => qua Rti => qua diode D4 v u dy m chu k m, in p trn cun th cp o chiu ( u dy trn m, di dng) dng in i qua D2 => qua Rti => qua D3 v u dy m. Nh vy c hai chu k u c dng in chy qua ti.

Tng K cng sut - Audio Amply

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Ni dung : Tng khuch i cng xut dng Transistor, Phn tch nguyn l hot ng, Tng khuch i cng xut s dng IC, c im v tr khng v in p trn cc chn IC, Phng php xc nh IC v cc chn quan trong, Phng php o kim tra loa v tng khuch i cng xut. 1. Tng khuych i cng sut dng Transistor S tng khuych i cng sut s dng Transistor Nhim v ca cc linh kin :

Q3 : l Transistor tin khuch i v o pha tn hiu. Q4 : l Transistor cng sut khuch i bn chu k m Q5 : l Transistor cng sut khuch i bn chu k dng Volume : l Trit p iu chnh m lng C8 : l t ni tng cho tn hiu m tn qua, ngn p mt chiu li C9 : l t ra loa R9 v R10 l in tr nh thin cho n Q3, ng thi l mch hi tip m, hi tip tn hiu u ra tr li u vo, nhm tng cng tnh n nh cho mch cng sut R8 l in tr gnh ca n Q3 , ng thi nh thin cho n cng sut Q5 C7 : l t lc ngun cho tng cng sut C6 : l t lc ngun cho cc tng pha sau R7 : l in tr cp ngun cho cc tng pha sau D1 v D2 c phn cc thun to ra s st p khong 1,2V phn cc cho hai

n cng sut

Tng khuych i cng sut dng Transistor Phn tch nguyn l hot ng ca tng cng sut

Tn hiu m tn ra khi mch Equalizer c a vo u trit p Volume, tn hiu ly ra im gia trit p c bin thay i tu theo mc iu chnh ca ngi s dng => tn hiu c a qua t C8 i vo n Q3 khuch i, Q3 l n khuch i v bin in p, Q3 c nh thin sao cho UCE ca Q3 0,5Vcc ( t c gi tr ny ngi ta iu chnh R10 ) Hai n cng sut c mc y ko khuch i cho hai na chu k ca tn hiu, tn hiu vo B ra E do hai n cng sut khuch i v cng dng in Tn hiu ly ra t chn E ca hai n cng sut c cng mnh c ghp qua t C9 a ra loa Ngun nui ca mch trn c th thay i t 6V n 12V, khi thay i ngun nui ta ch vic thay i R10 thu c UCE ca hai n cng sut cn bng. Cc bn c th lp mch trn theo cc thng s ghi trong phn t lp Cassette.

2. Tng khuch i cng sut dng IC Khi nim v IC cng sut : IC l vit tt ca t Intergated Circuit ngha l mch tch hp : l mch in t gm nhiu linh kin tch hp trong mt khi duy nht thc hin mt hay nhiu chc nng , th d IC cng sut m tn th lm chc nng khuch i cng sut m tn, IC tng trong Ti vi mu c th thc hin hng chc cc chc nng khc nhau.

IC khuch i cng sut m tn trong Cassette Vi mch s dng IC khuch i cng sut ta cn nm c cc im chnh sau :

Chn cp ngun Vcc cho IC Chn nhn tn hiu vo Audio in Chn a tn hiu ra loa Audio out

c im v in p v tr khng ca cc chn IC

IC cng sut m tn thc cht l mt t hp Transistor c mc theo kiu trc tip, trong hai n cng sut c mc y ko v vy in p u ra loa ( Chn s 2) lun c gi tr = 1/2 Vcc Nu ta o tr khng ( bng thang x1) gia chn cp ngun vi Mass th chiu o thun ( que en vo +Vcc, que vo mass) phi c tr khng ln , khi o li => c tr khng nh. Khi cp ngun, nu dng tay cm Tvt chm vo chn Audio in phi c ting loa. => Tri vi cc c im trn l du hiu ca IC cng sut b hng

Phng php x nh IC cng sut v cc chn quan trng

IC cng sut l IC c to nhit . L IC c ng lin lc ra loa.

Chn cp ngun Vcc l chn ni vi cc dng ca t lc ngun (t ho to nht khu vc cng xut ) Chn ra loa : xc nh chn ra loa, ta phi d ngc t Loa v qua t ra loa . Chn Audio in : Ta c th xc nh chn ny bng cch d t im gia ca trit p Volume qua t i vo chn Audio in ca IC

IC khuch i cng sut m tn Phng php kim tra loa v tng khuch i cng sut Hng loa : Biu hin ca hng loa l khng c ting hoc ting b d.

Kim tra : ng h thang x1 qut qut vo hai u mi hn trn loa, nu c ting st st v o thy tr khng bo t 4 - 8 l loa cn tt . Trng hp loa b d => thng do loa b chm cn, ta th bng cch n nh tay ln mng loa, nu loa b chm cn th nghe c ting st ct.. Hng IC cng xut : IC cng sut thng hng hai trng hp :

Chp chn cp ngun ( c th lm hng theo b ngun ) in p chn ra loa b lch.( thng thng chn ra loa = 1/2 Vcc ) Biu hin => Mt ting ra loa hoc ting b nght mi.

Cc bc kim tra tng cng sut :

Xc nh ng IC cng sut (l IC duy nht c to nhit trong my) Xc nh ng chn cp ngun Vcc cho IC cng sut ( da vo t lc to nht cnh IC cng sut, in p Vcc i qua cc dng ca t lc. ng h thang x1 , o tr khng gia chn Vcc vi mass, nu c hai chiu o kim ng h ln = 0 l IC b chp. Nu chiu o thun (que en vo dng , que vo mass) kim ln mt cht, o chiu que o, kim khng ln => l IC c tr khng bnh thng.

Nu IC c tr khng bnh thng th cp ngun v kim tra in p. o chn Vcc so vi mass phi c 9 - 12V ( bng in p quy nh ca my ), nu chn Vcc khng c in th kim tra li ngun, chuyn mch Function, cng tc SW trn b c. Nu chn Vcc c in p, ta kim tra chn ra loa ( ti IC ) phi c in p = 50% Vcc, th d Vcc = 12V th chn ra loa phi c 6V, nu in p ny lch qu 10% l hng IC. Tt c cc in p o u bnh thng th ta tng Volume ln v dng t vt nh g vo im gia trit p Volume phi c ting ra loa => Nu khng c ting ng cng l hng IC

Phng php kim tra t in.

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Ni dung : Phng php o kim tra t giy v t gm, Phng php kim tra t ho. 1. o kim tra t giy v t gm. T giy v t gm thng hng dng b d r hoc b chp, pht hin t d r hoc b chp ta quan st hnh nh sau y .

o kim tra t giy hoc t gm .

hnh nh trn l php o kim tra t gm, c ba t C1 , C2 v C3 c in dung bng nhau, trong C1 l t tt, C2 l t b d v C3 l t b chp. Khi o t C1 ( T tt ) kim phng ln 1 cht ri tr v v tr c. ( Lu cc t nh qu < 1nF th kim s khng phng np )

Khi o t C2 ( T b d ) ta thy kim ln lng chng thang o v dng li khng tr v v tr c. Khi o t C3 ( T b chp ) ta thy kim ln = 0 v khng tr v. Lu : Khi o kim tra t giy hoc t gm ta phi ng h thang x1K hoc x10K, v phi o chiu kim ng h vi ln khi o.

2. o kim tra t ho T ho t khi b d hay b chp nh t giy, nhng chng li hay hng dng b kh ( kh ho cht bn trong lp in mi ) lm in dung ca t b gim , kim tra t ho , ta thng so snh phng np ca t vi mt t cn tt c cng in dung, hnh nh di y minh ho cc bc kim tra t ho.

o kim tra t ho

kim tra t ho C2 c tr s 100F c b gim in dung hay khng, ta dng t C1 cn mi c cng in dung v o so snh. ng h thang t x1 n x100 ( in dung cng ln th thang cng thp ) o vo hai t v so snh phng np , khi o ta o chiu que o vi ln. Nu hai t phng np bng nhau l t cn kim tra cn tt, trn ta thy t C2 phng np km hn do t C2 trn b kh. Trng hp kim ln m khng tr v l t b d.

Ch : Nu kim tra t in trc tip trn mch , ta cn phi ht rng mt chn t khi mch in, sau kim tra nh trn.

Mch chnh m sc - Equalizer

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Ni dung : Nhim v ca mch Graphic Equalizer, Mch iu chnh Bass - Treec, Mch Equalizer 5 cn gt, Phng php kim tra sa cha tng Equalizer 1. Nhim v ca mch Graphic Equalizer Equalizer l mch iu chnh s cn bng tn hiu gia cc tn s trong gii tn m thanh, cn gi l mch iu chnh m sc, n gin nht ca mch Equalizer l mch Bass Treec vi hai nm chnh, thng thng mch Equa lizer c 5 cn gt chnh cho 5 vng tn s l 100Hz, 300Hz, 1KHz, 3KHz v 10KHz. T kin thc vt l PTTH ta bit rng, m thanh con ngi nghe c c gii tn t 20Hz n 20KHz v gi l tn hiu m tn, tn s nh hn 20Hz gi l h tn, tn s t 20KHz n 30KHz gi l sng siu m, cn tn s trn 30KHz l sng cao tn. Gii tn m thanh m con ngi c th cm nhn t 20Hz n 20 KHz nhng cc thit b m thanh thng b hn ch v mt tn s. Th d i Cassette thng ch truyn t c gii tn t 50Hz n 10 KHz, in thoi di ng ch truyn t c gii tn t 300Hz n 3KHz, cc thit b cho di tn tt l u a CD, my nghe nhc k thut s.

Di tn s m con ngi s dng trong lnh vc in t.

Vng tn s ca nm chnh Bass - Treec

Gii tn m thanh con ngi nghe c l minh ho bng ng mu tm t 20Hz n 20KHz. Gii tn m thanh m Radio - Cassette c th t c minh ho bng ng mu , t khong 50Hz n khong 12KHz Nm Bass l chnh li cho vng tn s khong 100Hz., y l vng tn s ca cc m trm nh ting trng, ting m m.. Nm Treec l chnh li cho vng tn s khong 10KHz , y l vng tn s ca cc m bng nh ting xng .. Vng tn s t 1KHz n 3KHz t thay i khi ta chnh Bass treec, y l vng tn

s ca ging ht ca s, ging pht m ca con ngi. S mch iu chnh Bass - Treec

S nguyn l ca mch iu chnh Bass - Treec

Tn hiu m tn t tng Radio hoc tng Khuch i u t a sang i vo tng Equalizer theo ng Audio Input Cc tn s cao i qua t 1nF i vo trit p Treec, cc tn s thp b t cn li, nh vy tn hiu i vo trit p Treec ch c thnh phn tn s cao, T 10nF sau trit p Treec gi li tn s thp u ra khng b u tt xung mass. Mt phn tn hiu i qua R22K i vo trit p Bass, cc tn s cao thot qua t 0,1F v khng i vo trit p Bass, nh vy tn hiu i vo trit p Bass ch c thnh phn tn s thp. Tn hiu u ra ly t im gia ca hai trit p c tp trung li v a sang trit p chnh m lng Volume, sau c a sang tng cng sut khuych i . Bn c th t lp mch Bass - treec nh cc thng s ca s trn, Cc trit p Bass - Treec bn mua loi 100K nh hnh di

Trit p 100K dng lp mch Bass treec v trit p Volume 3. Mch Equalizer c 5 cn gt. c th iu chnh c nhiu vng tn s hn , ngi ta thng lp mch Equalizer c 5 cn gt .

Di tn iu chnh ca mch Equalizer 5 cn gt.

S mch Equalizer 5 cn gt s dng IC Bn c th thit k mch Equalizer 5 cn gt nh cc thng s ca s trn, sau bn c th s dng vo tng m hoc b kch cho loa thng.., ngun in nui Vcc cho IC l 6V DC. 4. Phng php kim tra sa cha tng Equalizer Khi hng tng Equaizer thng sinh ra cc hin tng nh . Mt m thanh ra loa trong khi bng vn quay, hoc m thanh ni nh, hoc iu chnh cc cn gt t tc dng. Kim tra :

Khi kim tra Equalizer bn cn kim tra Loa v tng khuch i cng sut trc, v chc chn rng tng cng sut hot ng tt Dng xng hoc l RP7 st vo cc trit p Bass -Treec hoc cc cn gt, loi tr bnh khng tip xc. o kim tra Vcc cho IC mch Equalizer, thng thng IC ny nm ngay cnh cc cn gt iu chnh tn s, chn Vcc l chn c t ho 47F hoc t 100F lc ngun, in p ny phi c 6V DC Nu mt Vcc cho IC Equalizer bn cn d ngc li theo ng in p ny v pha IC cng sut tm ra mch n p gm 1 n v 1 diode zenner, bn hy kim tra n v Diode zener ny . Cui cng nu in p c th bn hy u tt t u tn hiu vo Audio in n u ra Audio out ca mch Equalizer, nu c m thanh th l do hng IC Equalizer.

S mch cp ngun cho tng Equalizer

Kim tra Mosfet - ng dng Mosfet0 Comment Size- Size+ 21/12/2009 Other... RSS

Ni dung : Phng php o xc nh Mosfet cn tt, Mosfet b hng. ng dng ca Mosfet trong thc t, Kim tra Mosfet trong mch in. 1. o kim tra Mosfet

Mt Mosfet cn tt : L khi o tr khng gia G vi S v gia G vi D c in tr bng v cng ( kim khng ln c hai chiu o) v khi G c thot in th tr khng gia D v S phi l v cng.

Cc bc kim tra nh sau :

o kim tra Mosfet ngc thy cn tt.

Bc 1 : Chun b thang x1K Bc 2 : Np cho G mt in tch ( que en vo G que vo S hoc D ) Bc 3 : Sau khi np cho G mt in tch ta o gia D v S ( que en vo D que vo S ) => kim s ln. Bc 4 : Chp G vo D hoc G vo S thot in chn G. Bc 5 : Sau khi thot in chn G o li DS nh bc 3 kim khng ln. => Kt qu nh vy l Mosfet tt.

o kim tra Mosfet ngc thy b chp

Bc 1 : ng h thang x 1K o gia G v S hoc gia G v D nu kim ln = 0 l chp o gia D v S m c hai chiu o kim ln = 0 l chp D S

2. ng dung ca Mosfet trong thc t Mosfet trong ngun xung ca Monitor

Mosfet c s dng lm n cng xut ngun Monitor Trong b ngun xung ca Monitor hoc my vi tnh, ngi ta thng dng cp linh kin l IC to dao ng v n Mosfet, dao ng to ra t IC c dng xung vung c a n chn G ca Mosfet, ti thi im xung c in p > 0V => n Mosfet dn, khi xung dao ng = 0V Mosfet ngt => nh vy dao ng to ra s iu khin cho Mosfet lin tc ng ngt to thnh dng in bin thin lin tc chy qua cun s cp => sinh ra t trng bin thin cm ng ln cc cun th cp => cho ta in p ra. * o kim tra Mosfet trong mch . Khi kim tra Mosfet trong mch , ta ch cn thang x1 v o gia D v S => Nu 1 chiu kim ln o chiu o kim khng ln => l Mosfet bnh thng, Nu c hai chiu kim ln = 0 l Mosfet b chp DS.

Bin p0 Comment Size- Size+ 21/12/2009 Other... RSS

Ni dung : Cu to v hot ng ca bin p ngun, Bin p m tn , Bin p xung, Cao p. 1. Cu to ca bin p. Bin p l thit b bin i in p xoay chiu, cu to bao gm mt cun s cp ( a in p vo ) v mt hay nhiu cun th cp ( ly in p ra s dng) cng qun trn mt li t c th l l thp hoc li ferit .

K hiu ca bin p

2. T s vng / vol ca bin p .

Gi n1 v n2 l s vng ca qun s cp v th cp. U1 v I1 l in p v dng in i vo cun s cp U2 v I2 l in p v dng in i ra t cun th cp.

Ta c cc h thc nh sau : U1 / U2 = n1 / n2 vng dy qun. in p trn hai cun dy s cp v th cp t l thun vi s

U1 / U2 = I2 / I1 Dng in trn hai u cun dy t l nghch vi in p, ngha l nu ta ly ra in p cng cao th cho dng cng nh. 3. Cng xut ca bin p . Cng xut ca bin p ph thuc tit din ca li t, v ph thuc vo tn s ca dng in xoay chiu, bin p hot ng tn s cng cao th cho cng xut cng ln. 4. Phn loi bin p . * Bin p ngun v bin p m tn:

Bin p ngun hnh xuyn

Bin p ngun Bin p ngun thng gp trong Cassete, mply .. , bin p ny hot ng tn s in li 50Hz , li bin p s dng cc l Tnsilic hnh ch E v I ghp li, bin p ny c t s vng / vol ln. Bin p m tn s dng lm bin p o pha v bin p ra loa trong cc mch khuych i cng xut m tn,bin p cng s dng l Tnsilic lm li t nh bin p ngun, nhng l tnsilic trong bin p m tn mng hn trnh tn hao, bin p m tn hot ng tn s cao hn , v vy c s vng vol thp hn, khi thit k bin p m tn ngi

ta thng ly gi tr tn s trung bnh khong 1KHz - n 3KHz. * Bin p xung & Cao p .

Cao p

Bin p xung Bin p xung l bin p hot ng tn s cao khong vi chc KHz nh bin p trong cc b ngun xung , bin p cao p . li bin p xung lm bng ferit , do hot ng tn s cao nn bin p xung cho cng xut rt mnh, so vi bin p ngun thng thng c cng trng lng th bin p xung c th cho cng xut mnh gp hng chc ln.

Cc loi Diode

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Ni dung : Tm hiu cu to v cng dng ca cc loi Diode : Diode n p, Diode thu quang, Diode pht quang, Diode bin dung, Diode xung, Diode tch sng, Diode nn in. 1. Diode Zener * Cu to : Diode Zener c cu to tng t Diode thng nhng c hai lp bn dn P N ghp vi nhau, Diode Zener c ng dng trong ch phn cc ngc, khi phn cc thun Diode zener nh diode thng nhng khi phn cc ngc Diode zener s gim li mt mc in p c nh bng gi tr ghi trn diode.

Hnh dng Diode Zener ( Dz )

K hiu v ng dng ca Diode zener trong mch.

S trn minh ho ng dng ca Dz, ngun U1 l ngun c in p thay i, Dz l diode n p, R1 l tr hn dng. Ta thy rng khi ngun U1 > Dz th p trn Dz lun lun c nh cho d ngun U1 thay i. Khi ngun U1 thay i th dng ngc qua Dz thay i, dng ngc qua Dz c gi tr gii hn khong 30mA. Thng thng ngi ta s dng ngun U1 > 1,5 => 2 ln Dz v lp tr hn dng R1 sao cho dng ngc ln nht qua Dz < 30mA.

Nu U1 < Dz th khi U1 thay i p trn Dz cng thay i Nu U1 > Dz th khi U1 thay i => p trn Dz khng i. 2. Diode Thu quang. ( Photo Diode ) Diode thu quang hot ng ch phn cc nghch, v diode c mt ming thu tinh nh sng chiu vo mi P - N , dng in ngc qua diode t l thun vi cng nh sng chiu vo diode.

K hiu ca Photo Diode

Minh ho s hot ng ca Photo Diode 3. Diode Pht quang ( Light Emiting Diode : LED ) Diode pht phang l Diode pht ra nh sng khi c phn cc thun, in p lm vic ca LED khong 1,7 => 2,2V dng qua Led khong t 5mA n 20mA Led c s dng lm n bo ngun, n nhy trang tr, bo trng thi c in . vv...

Diode pht quang LED 4. Diode Varicap ( Diode bin dung ) Diode bin dung l Diode c in dung nh t in, v in dung bin i khi ta thay i in p ngc t vo Diode.

ng dng ca Diode bin dung Varicap ( VD ) trong mch cng hng

hnh trn khi ta chnh trit p VR, in p ngc t vo Diode Varicap thay i , in dung ca diode thay i => lm thay i tn s cng hng ca mch. Diode bin dung c s dng trong cc b knh Ti vi mu, trong cc mch iu chnh tn s cng hng bng in p.

5. Diode xung Trong cc b ngun xung th u ra ca bin p xung , ta phi dng Diode xung chnh lu. diode xung l diode lm vic tn s cao khong vi chc KHz , diode nn in thng thng khng th thay th vo v tr diode xung c, nhng ngc li diode xung c th thay th cho v tr diode thng, diode xung c gi thnh cao hn diode thng nhiu ln. V c im , hnh dng th Diode xung khng c g khc bit vi Diode thng, tuy nhin Diode xung thng c vng dnh du t nt hoc nh du bng hai vng

K hiu ca Diode xung 6. Diode tch sng. L loi Diode nh v bng thu tinh v cn gi l diode tip im v mt tip xc gia hai cht bn dn P - N ti mt im trnh in dung k sinh, diode tch sng thng dng trong cc mch cao tn dng tch sng tn hiu. 7. Diode nn in. L Diode tip mt dng nn in trong cc b chnh lu ngun AC 50Hz , Diode ny thng c 3 loi l 1A, 2A v 5A.

Diode nn in 5A

Tng K cng sut - Audio Amply

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Ni dung : Tng khuch i cng xut dng Transistor, Phn tch nguyn l hot ng, Tng khuch i cng xut s dng IC, c im v tr khng v in p trn cc chn IC, Phng php xc nh IC v cc chn quan trong, Phng php o kim tra loa v tng khuch i cng xut. 1. Tng khuych i cng sut dng Transistor S tng khuych i cng sut s dng Transistor Nhim v ca cc linh kin :

Q3 : l Transistor tin khuch i v o pha tn hiu. Q4 : l Transistor cng sut khuch i bn chu k m Q5 : l Transistor cng sut khuch i bn chu k dng Volume : l Trit p iu chnh m lng C8 : l t ni tng cho tn hiu m tn qua, ngn p mt chiu li

C9 : l t ra loa R9 v R10 l in tr nh thin cho n Q3, ng thi l mch hi tip m, hi tip tn hiu u ra tr li u vo, nhm tng cng tnh n nh cho mch cng sut R8 l in tr gnh ca n Q3 , ng thi nh thin cho n cng sut Q5 C7 : l t lc ngun cho tng cng sut C6 : l t lc ngun cho cc tng pha sau R7 : l in tr cp ngun cho cc tng pha sau D1 v D2 c phn cc thun to ra s st p khong 1,2V phn cc cho hai n cng sut

Tng khuych i cng sut dng Transistor Phn tch nguyn l hot ng ca tng cng sut

Tn hiu m tn ra khi mch Equalizer c a vo u trit p Volume, tn hiu ly ra im gia trit p c bin thay i tu theo mc iu chnh ca ngi s dng => tn hiu c a qua t C8 i vo n Q3 khuch i, Q3 l n khuch i v bin in p, Q3 c nh thin sao cho UCE ca Q3 0,5Vcc ( t c gi tr ny ngi ta iu chnh R10 ) Hai n cng sut c mc y ko khuch i cho hai na chu k ca tn hiu, tn hiu vo B ra E do hai n cng sut khuch i v cng dng in Tn hiu ly ra t chn E ca hai n cng sut c cng mnh c ghp qua t C9 a ra loa Ngun nui ca mch trn c th thay i t 6V n 12V, khi thay i ngun nui ta ch vic thay i R10 thu c UCE ca hai n cng sut cn bng.

Cc bn c th lp mch trn theo cc thng s ghi trong phn t lp Cassette.

2. Tng khuch i cng sut dng IC Khi nim v IC cng sut : IC l vit tt ca t Intergated Circuit ngha l mch tch hp : l mch in t gm nhiu linh kin tch hp trong mt khi duy nht thc hin mt hay nhiu chc nng , th d IC cng sut m tn th lm chc nng khuch i cng sut m tn, IC tng trong Ti vi mu c th thc hin hng chc cc chc nng khc nhau.

IC khuch i cng sut m tn trong Cassette Vi mch s dng IC khuch i cng sut ta cn nm c cc im chnh sau :

Chn cp ngun Vcc cho IC Chn nhn tn hiu vo Audio in Chn a tn hiu ra loa Audio out

c im v in p v tr khng ca cc chn IC

IC cng sut m tn thc cht l mt t hp Transistor c mc theo kiu trc tip, trong hai n cng sut c mc y ko v vy in p u ra loa ( Chn s 2) lun c gi tr = 1/2 Vcc Nu ta o tr khng ( bng thang x1) gia chn cp ngun vi Mass th chiu o thun ( que en vo +Vcc, que vo mass) phi c tr khng ln , khi o li

=> c tr khng nh. Khi cp ngun, nu dng tay cm Tvt chm vo chn Audio in phi c ting loa. => Tri vi cc c im trn l du hiu ca IC cng sut b hng

Phng php x nh IC cng sut v cc chn quan trng

IC cng sut l IC c to nhit . L IC c ng lin lc ra loa. Chn cp ngun Vcc l chn ni vi cc dng ca t lc ngun (t ho to nht khu vc cng xut ) Chn ra loa : xc nh chn ra loa, ta phi d ngc t Loa v qua t ra loa . Chn Audio in : Ta c th xc nh chn ny bng cch d t im gia ca trit p Volume qua t i vo chn Audio in ca IC

IC khuch i cng sut m tn Phng php kim tra loa v tng khuch i cng sut Hng loa : Biu hin ca hng loa l khng c ting hoc ting b d.

Kim tra : ng h thang x1 qut qut vo hai u mi hn trn loa, nu c ting st st v o thy tr khng bo t 4 - 8 l loa cn tt . Trng hp loa b d => thng do loa b chm cn, ta th bng cch n nh tay ln mng loa, nu loa b chm cn th nghe c ting st ct.. Hng IC cng xut : IC cng sut thng hng hai trng hp :

Chp chn cp ngun ( c th lm hng theo b ngun ) in p chn ra loa b lch.( thng thng chn ra loa = 1/2 Vcc ) Biu hin => Mt ting ra loa hoc ting b nght mi.

Cc bc kim tra tng cng sut :

Xc nh ng IC cng sut (l IC duy nht c to nhit trong my) Xc nh ng chn cp ngun Vcc cho IC cng sut ( da vo t lc to nht cnh IC cng sut, in p Vcc i qua cc dng ca t lc. ng h thang x1 , o tr khng gia chn Vcc vi mass, nu c hai chiu o kim ng h ln = 0 l IC b chp. Nu chiu o thun (que en vo dng , que vo mass) kim ln mt cht, o chiu que o, kim khng ln => l IC c tr khng bnh thng. Nu IC c tr khng bnh thng th cp ngun v kim tra in p. o chn Vcc so vi mass phi c 9 - 12V ( bng in p quy nh ca my ), nu chn Vcc khng c in th kim tra li ngun, chuyn mch Function, cng tc SW trn b c. Nu chn Vcc c in p, ta kim tra chn ra loa ( ti IC ) phi c in p = 50% Vcc, th d Vcc = 12V th chn ra loa phi c 6V, nu in p ny lch qu 10% l hng IC. Tt c cc in p o u bnh thng th ta tng Volume ln v dng t vt nh g vo im gia trit p Volume phi c ting ra loa => Nu khng c ting ng cng l hng IC

H thng m thanh tham chiu ti Hi-end Show 2009

Nhng h thng m thanh tham chiu ti Hi-end Show din ra 25/9 ti l nhng sn phm u bng ln u xut hin ti Vit Nam. Di y l danh sch nhng h thng phi ghp d kin. Magico, Ayre, Wadia v Crystal Cable

B loa Magico V2 dng hai loa mid/bass ng knh 7 inch.. Vic xut hin ca Magico ti trin lm Vit Nam Hi-end Show nm nay l mt tin ng mng cho audiophile bi y l dp him hoi th thng thc mt trong nhng sn phm m thanh c xp hng u th gii. B loa Magico V2 c di tn hot ng t 32 n 40.000 Hz, dng 2 loa mid/bass ng knh 7 inch vi cng ngh mng c o NeoTech. y l thit k loa con u tin trn th gii s dng mng lm t cng ngh k thut cao Nanotube. Magico V2 c chng rung kh tt vi thng lm t g p 17 lp, bn cnh , mt trc (dng gi loa) v mt sau dng 2 tm nhm my bay 6061T cao cp tng trng lng v n nh. i Magico V2 c phi ghp vi h thng ngun khuch i chun tham chiu Ayre MX-R v KX-R. y l b sn phm c cc chuyn gia m thanh th gii nh gi rt cao v vinh d nhn c nhiu gii thng danh gi trong c gii thng ng ch nht Sn phm ca nm, do tp ch Stereophile (M) trao tng. MX-R v KX-R s hu chassis my bng nhm dng thit k monocoque, thn my cng chnh l mt khi nhm c c phay thnh hnh, cng nh khot rng rut t linh kin. Chnh v th, cc linh kin c gi c nh, chc chn, thot nhit nhanh. Tng t nh cc thit k khuych i khc ca Ayre, MX-R dng mch cn bng, khng hi tip, phn cng sut s dng bn dn loi ThernalTrack c kh nng kim sot nhit ch ng trong thi gian thc. Ayre MX-R c cng sut 300 Watt mt knh (8 ohm), ha hn s lm ch i Magico V2 mt cch d dng. H thng s khng hon ho nu thiu mt trong nhng chic preamp hng u th gii, Ayre KX-R. Preamp Ayre KX-R s dng mch c bit c tn Variable Gain Transimpedance (VGT). Mch VGT khng lm suy gim tn hiu u vo v gip duy

tr t s S/N thp mi mc m lung. Thc t cho n nay, ch c mt vi hng sn xut trn th gii ng dng thit k mch ny.

u c hi-end Wadia. H thng ngun m cung cp cho b Magico-Ayre cng l mt tn tui ng hng top ca nhng nh sn xut u c hi-end, Wadia. Sn phm u bng ca Wadia, chic CD 781i s hu trn b nhng cng ngh nh cao ca hng t thit k ngun, gii m v cng sut nh: DigiMaster, ClockLink, SwiftCurrent... u c ny dng 2 chp x l tn hiu kt hp vi phn mm upsampling Digimaster 2.5 nng tn s ly mu ln mc 1.4112 kHz phn gii 24Bit. c bit, nhiu nn ca CD c h n mc thp nht nh b lc cho c phn ngun digital ln ngun analog, to nng lng sch np vo t. Bn cnh , vic b tr cc bo ngun n p ring cho phn x l k thut s, b clock, x l D-A, tng cng sut... gip Wadia 781i hot ng cc k n nh, hn ch nhiu ti a. H thng cn c trang b mt "v kh ti thng" nhm mang li s trnh din ti a ca cc thit b - h thng dy dn Dreamline u bng ca Crystal Cable. y l mt trong nhng dng cp cao cp nht hin nay c dng kt ni nhng b dn hng triu USD. Vi cng ngh luyn kim c bit kt hp gia cht liu vngbc, dy Dreamline c li bc, cc khong h gia cc phn t bc c lp y bng vng nguyn cht to thnh mt cht liu li c tnh cht gn nh siu dn. Cht liu bc-vng ca dng Dreamline c tinh khit ln n 99,9999999%. Vi u im chng nhiu hon ho, dy Dreamline ngoi cc lp bo v nh Kapton, telflon, dy bn bng vng/bc cn s hu mt cht liu c bit c gi b mt ring. Vi nhng thit b hu ht l cc sn phm u bng, s phi ghp gia Magico, Ayre, Wadia v Crystal Cable l mt trong nhng ng c vin nng k cho gii thng H thng n tng ti Vit Nam Hi-end Show 2009. C th d on trc kh nng trnh din ca h thng m phong cch hi-end hin i vi kh nng th hin di tn tuyn tnh, m thanh cc di trung, cao chnh xc, di trm su, gn. Bn cnh , b dn vn gi c mc v m cn thit nh s gp mt ca Ayre, Wadia v Crystal Cable. Chnh s trnh din c m v mc kt hp vi tnh chnh xc, ng cao s l mt quy chun cho m thanh hi-end hin i.

Sonus Faber v Unison

Loa Sonus Faber Amati Anniversario. Cc thit b t loa n ampli, u c u n t n nc ca thp nghing Pisa. S phi hp ny c cho l n vi cng mt gu m thanh ng nht trong mt phong cch trnh din sang trng. Sonus Faber Amati Anniversario l mt trong nhng sn phm c tp ch Stereosound (Nht Bn) nh gi rt cao v kh nng trnh din. Amati thuc dng Homage u bng ca Sonus Faber. N s hu nhng k thut v trit l ca model cao cp nht Stradivari. i loa ny c thit k thng mang hnh dng n lut, c

tc dng iu ha cng hng bn trong, mang li kh nng trnh din m thanh tht nht c th. y l thit loa 3 ng ting gm treble ScanSpeak Ring Radiator ng knh 25 mm, mid dng cht liu CCAW/Kapton c ng knh 150 mm v 2 loa wooofer 220 mm dng voice-coil c bit bng hn hp magi v nhm cc nh. im c bit nht ca loa Amati Anniversario so vi cc model Sonus Faber khc chnh l thit k l thot hi dng hnh ch nht dnh cho c loa woofer v mid (thay v dng l thot hi trn truyn thng). Loa hot ng tr khng 4 ohm, nhy 92 dB cho di tn t 24 n 30.000 Hz.

Ampli Unison Research Performance. to nn mt b i tm c, h thng ngun khuch i Unison Research Performance, cng n t Italia, c "triu tp" vo i hnh. Mc d l ampli tch hp nhng khi thit k honh trng Performance cha n 3 module bn trong bao gm 2 poweramp mono v phn tin khuch i. Ampli ny dng 3 bng KT88 cho phn cng sut 40 Watt mi knh. i vi phn preamp, Performance s dng kt hp 2 bng 12AU7 v 2 bng 12AX7. Unison Reseach Performance t thit k v ch to bin th xut m ring ca mnh nhm m bo cht lng m thanh ti u. Phn ngun digital dnh cho h thng khng g hp hn bng vic dng u pht Unison Research Unico CD. Giovanni Sachetti, ch nhn ca Unison Research kt hp vi gio s Leopoldo Rossetto, i hc Padua, ngnh in t ng dng, cng nhau nghin cu pht trin Unico CD. C hai quyt nh chn b c CD-Rom c chn lc k lng, gii m Cirrus Logic Crystal CS4392 24 bit / 192 kHz cng vi b ngun ln tng t nh tiu chun ca ngun ampli. im ni tri v thit k mch ca Unico CD l sn phm s dng mch Class A cn bng dng n 3 cc 5814/A mi bn cho tng khuch i kt hp vi tng cng sut dng bn dn. Unico CD c nhn xt l u CD c mc gi thp n kh tin so vi nhng cng ngh m n c trang b. Mt phong cch Italy r nt s c ti hin mt cch sang trng. y chc chn l h thng c "ngt" ting hng u, nhng ng cho rng s mm mi v uyn chuyn ca n in t s ly mt i kh nng trnh din chi tit v chnh xc.

Marantz v DLS

u CD SA-KI c nng cp t SA-15-S2. Marantz va cho ra mt b i Ampli/CD KI Pearl nhn k nhim 30 nm cng tc gia k s m thanh ti ba Ken Ishiwata v thng hiu Marantz. "Ph thy" Ken Ishiwata hin l Gim c thng hiu Marantz, s hu i bn tay k diu. Nhng sn phm Marantz tiu chun qua tay ng u tr thnh nhng tc phm m thanh "KI" c ngi snh chi sn lng. Chic ampli tch hp Marantz KI Pearl l sn phm pht trin t model PM-15S1. Nhng ci tin v mt thit k ngoi bao gm cc nng cp v dy ca chassis (thm 5 mm), s dng cc chn ln chng rung tt u c thc hin c ampli PM-KI v CD SA-KI (nng cp t SA-15-S2). Ring ampli KI Pearl c trang b bin th ngun xuyn bc ng chng nhiu t tnh, cc module op-amp c trng b 2 loi HDAM SA-2 v HDAM SA-3 mi nht. PM-KI c thit k 2 tng main v preamp tch bit bng mt lp ng cch ly chng nhiu cho cng sut 90 Watt mi knh (8 ohm). Cc nh thit k thng thng tm mi cch gim ti a t s mo S/N, nhng i vi Ken Ishiwata, ng cho rng thng s k thut cng ch l nhng thng s, mang li kh nng trnh din ti u, ngi ta phi cm nhn v nh gi bng chnh i tai, gi tr ca cc sn phm mang nhn KI l s nn nt, tinh chnh cht m qua i tai ca Ken Ishiwata. Marantz SA-KI c ngun gc t chic SACD ot nhiu gii thng, SA-15S2. SA-KI vn tin dng chip gii m Cirrus Logic CS4398, nhng trang b b c tt hn SACDM10 vi phn khay a ca XYRON. Tng t nh PM-KI, mch v cc linh kin quan trng bn trong u c ny u c bc ng cch li. SA-KI cng cho php chn b lc thch hp vi dc thp ch tiu chun v lc tuyn tnh. Mt trong nhng tin ch khng th khng nhc n ca SA-KI l bn c th dng u c ny nh mt thit b gii m D/A, gip chuyn i tn hiu digital t cc file nhc khng nn lu trong iPod hoc my tnh qua dock ni thch hp thnh analog v xut ra ampli. y l trang b hu ch cho nhu cu chi nhc HD Tracks vn l mt xu hng ang c audiophile th gii s dng rng ri.

i loa DLS M66. Kt hp vi b i Marantz KI l i loa ln u tin xut hin ti Vit Nam DLS M66. DLS l thng hiu n t Thy in, sn phm ca hng ni ting cho cht m m p vi cc di trung cao mm mi. DLS M66 c kiu dng loa ct hin i, thng loa c sn bng piano, cc loa con gi vng mt trc trn mt tm g ring bit. Loa s hu driver treble dom la 28 mm cng b i loa mid/bass ng knh 150 mm dng cht liu mng nhm cc nh. Cc loa con DLS s dng nam chm c bit c t tnh cc mnh, phn chassis u c c nguyn khi. Tng t nh cc thit k loa Bc u, DLS M66 c tr khng 4 ohm, di tn hot ng t 40 n 30 kHz vi nhy 89 dB. y l h thng c tm gi khim tn nht trong 4 b dn ny, nhng li c gi tr nht show nm nay. Vi mt phong cch trnh din giu tnh cm, DLS M66 lp tc gy n tng i vi ngi nghe, thm vo l hng v "Ken Ishiwata" ni ting cng lm cho bc tranh m thanh thm m . JBL v Mark Levinson

i loa Everest DD66000 u bng ca JBL. Mc d xut hin ti Vit Nam t hn hai nm nay nhng y l mt trong nhng c hi him hoi m ngi chi m thanh c dp thng thc i loa u bng ca thng hiu JBL, Everest DD66000. Everest DD66000 c trng lng ln n 142 kg mi loa, c thit k vi b ngang ln ln n gn 1 mt. Sn phm u bng ca JBL ng dng nhng cng ngh ch to c loa tin tin nht ca hng. Di cao ca Everest c kh nng ti di cao ln n 50.000 Hz, dng thit k treble ci vi mng Berylium cao cp. Tng t nh loa treble, loa mid dng c 466Be vi kiu ci Bi Radial Horn c ming ci i xng, loa mid ny s hu driver mng Berylium ng knh 100 mm. Di trm ca DD66000 kh honh trng vi s phi hp ca cp c 1501AL ng knh 380 mm trang b nam chm Alnico huyn thoi, vin cao su EPDM, mng ph lp Aquaplas c tc dng chng rung v hn ch cng hng. C cng trit l thit k vi cc sn phm thuc dng JBL Project K2, b phn tn ca DD66000 dng pin 9V to mt in th phn cc rt nh gip bias cc t bn trong, h thng mch phn tn s lun vn hnh ch class A, gim mo ting.

JBL Everest DD66000 c nhy ln n 96 dB. No.53, b i power mono u bng ca Mark Levinson l mt i tc hon ho ko i JBL DD66000. H thng khuch i No.53 c cc chuyn gia nh gi c kh nng trnh din m thanh vi trung thc rt cao. Mark Levinson No.53 l thit k ampli lai hybrid phi hp gia s ngt ngo ca mch Class A bn dn v cht mnh m, ch tit cao ca khuch i digital. Hng dng cng ngh khuch i digital ring ca mnh Interleaved Power Technology, cng ngh ny c kh nng gim nhiu bng cch y tp m chuyn mch v cc hiu ng xu m n tc ng vo m thanh ln ti mc cao hn rt nhiu so vi di tn nghe c ca con ngi. Ampli ny trang b bin th xuyn cng sut 2,8 kVA v h thng 4 t lc 47.000 uF cho cng sut 500 W mi knh (8 ohm). Kt hp vi poweramp No.53 l sn phm pream No.326S. Preamp ny c thit k rt cn trng vi cc mch khuch i, mch khin v mch ngun u c tch bit bng cc khi hp thp chng nhiu. Tn hiu in ngay t khi vo N.326S s c cho qua b lc loi b cc nhiu in t trng, nhiu radio.... m bo dng ngun khng lm nh hng n tn hiu analog nhy cm bn trong. Mc d l thit k tin khuch i nhng No.326S trang b n 2 bin th xuyn ring bit cho mch khuch i analog v mch khin.

u CD No.512 ca Mark Levinson. Thit b ngun m phc v cho h thng ny cng l mt sn phm nh cao ca Mark Levinson, u CD No.512. gii quyt nhiu jitter, loi nhiu nguy hi nht trong u CD, Mark Levinson s dng b nh m kt hp vi mch Direct Digital Synthesis. u c ny c trang b 2 bin th ngun ring cho mch digital v analog. Vi mi knh tn hiu, No.512 dng n 2 chip D/A 24Bit nhm gim nhiu S/N. y c xem l mt trong nhng thit k u c tt nht dnh cho nh dng a SACD. Vi nhng sn phm "nh" ca hai thng hiu lng danh JBL v Mark Levinson, khch tham quan s c "chiu i" mt bui tic m thnh honh trng vi kh nng th hin nhng a SACD vi chi tit v trung thc cao cha tng thy. Khng nhng th, uy lc v kh nng th hin ng cao cng l hai yu t c mong i b dn ny. =============