AUDIOLAB 8000A Modification

Hi, not sure how many of you here is using Audiolab 8000A. Just some sharing & hope get get some info from those expert here too.

The 8000A i have is with sn 89xxx, issue 4, estimate the product ~1990.
Photo attached is befrore modification.

Modification done:

1) Replace all ecap at pre &power amp & power suply side side to BG std/n

Result --> detail increase a lot, more natural (sound at 1st 15minute is terrible)

2) twisted the cable connect to RCA & also the cable from transformer (slightly cleaner & clearer).


next modification:

3) change 10000uF/50v reservoir to Jensen gold (still waiting the parts)

4) change the EVOX MMK to other pp cap (anybody here got advise for me, if i wish the sound will increase in warm, thick &natural?) pre amp side got 0.47uF x2, 0.33uFx2, 0.047uFx2, 0.033uFx2


Question:

anybody had separate 8000A to pre & power by remove the resistor in R(picture 1)? how's the effect?

muka,

推動管偏壓英文是？？ 是transformer吗？
我对华文电阻名词不太熟悉。。。 ops:
电阻看不清可用multimeter量。
你的8000A是issue4还是issue5?

Muka,

Have u find out the root cause of the burn?? i will try to take the close up picture today or tomorrow for you!

Is there any good method to increase the audiolab 60w power to ~80w?

muka,

attached 3 photo for u, hope it helps!

aharder,

:  : no need invite u also can see the post lah :
of couse 8000A is noisier than use 8000A as pre & 8000p Power...
1) 2 box always have less interference.
2) 60w & 100w is a lot difference too.
3) your 8000P had change all the e-cap to BG, whereas your 8000A is still using old 10yrs old ecap, definitely a lot different. My friend who use the same 8000A version as u who just change 3 cap in power side, he say the noise reduce >30%.
4) the way u use 8000A as pre is not the perfect way, the perfect way is u need to disconnect internally the pre&power in 8000A and use it as pre then only it can really perform as as pre!!! the 8000S had as switch in front panel, whenu press pre, it will disconnect the pre&power inside the 8000s internally... that's the main reason 8000S as a pre is better than 8000A. So u need to manually disconnect the 8000A PRE & POWER by remove the 2pc 560R resistor to get optimum performance as a pre.

my 8000A performance increase >30% after replace ~10pcs BG std even still use 15yrs old reservoir ecap.... if u really 12 compare the performance of 8000A, compare with my 8000A.

give me your email id so that i can pass u some other info on this.



So if u really 12 compare,

pls check the info of separate pre & power of 8000A at the web below!

http://www.hi-fi-insight.com/25/separating-the-pre-and-power-sections-on-an-audiolab-8000a.htm

If that's the case u shall look for 8000Q and not 8000S, if not later u may 12 change again to 8000Q. I'm not as ambitious as u, i'm happy with my 8000A with some modification. with rm400 it is enough for me to change all ecap with BG & big reservoir with jensen.

Since u like remote control so 8000C not suit u... :  :

[quote:8178356bd6="muka"]摩机必備線路圖，希望對你有帮助。 :
個人認為張電壓放大級電源斷開，外接regulator會對音質有正面的提升，改DC-SERVO的OPAMP也有帮助。[/quote]

Muka,

which model of opamp is a good replacement?

my IC is TL072CP (K8728)

Can give the website of the above article?

his comment acceptable..... but only base on unmodified unit.....

since u not planning to use turntable so 8000s is cost effective for u.... but i may play turntable as well.... : )

when u get your 8000px n want sell 8000p just let us now, maybe we will interested in it!

not see 8000lx before can show the photo of the back terminal?

Attached photo of my partially modified 8000A for sharing.
1) change e-cap at preamp&power side to BG stnd
2) twisted cable (power supply & to rca)
3) change evok mmk to ero mkt

Result detail/resolution&depth increase a lot, noice reduce, sound stage increase. more natural&musical.

Muka,
need your advice, refer the 3 e-cap (elna RE) circle in green colour in the picture, do u know it is for which circuit? is it for mm/mc or for ???

i also think like that but i found the 8000S which don't have phono stage also have this 3 ecap (470uf/16v x2, 470uf/35vx1), that's why i'm a bit curious.... if it is not for phono but for the power of 8000A then i may need to change it to better e-cap...

Kindly see the 8000S in picture

superwhite,

It is your 8000S but picture too blur, next time pls put under bright sun to take a clear photo lah! Go learn with aharder, u see his 8000C photo so clear!

Hi! i now only use 8000A as power amp only.

You can replace all the elna cap with blackgate in the pre amp section and the power supply side then you will get a lot more detail which u never heard before it will cost u ~(HKD500).

Anyway after play around with 8000A, i think 8000A has its limitation. So my advice is no need spend so much to mod 8000A, just mod the power supply side enough then go and DIY a tube preamp.

If u plan to get a 8000P then no need to mode 8000A, remove the M cap 10000uf and put in 8000P, then DIY a tube preamp and sell off 8000A.

only have experience on Mundorf film cap and no exp in mundorf E cap.

Dear Bryankeeper,

8000Q definitely better than 8000A peamp section.

If full tube (pre & power) then strong in vocal and most probably you will need to use full range speaker--> those who want strong & fast bass like me may not like it.

So my suggestion is to use tube preamp + solid state power amp --> u will have good & fast bass + little bit of tube feeling. A cheap tube preamp normally has better detail then a lot solid state preamp.

As we all know 8000A always been described as clinical--> compare to most entry level amp it is consider quite detail but it is not warm enough, not musical enough. Yes we can use blackgate to further improve the resolution, musicality and bass of it but it will still sound slightly thin... then we can change the 10000uf cap to jensen (orange/gold) colour--> it become warmer but u will need to sacrify little bit of bass tighness (jensen is warm sound but bass too soft), if u were to use 10000uf blackgate it will cost u a bomb.
For power amp CREEK(using 2 transformer) got a model better than 8000P.

i spend ~hkd 1500-2000 i can DIY a 5687 simple tube preamp which is better than 8000A's pream (better detail, warmer and more natural sound, bass also good when use with solid state power amp)

dear sugargar,

If u really wish to mod 8000S here's something u can try.

A) Change all the e-cap at preamp section & power supply to Blackgate (BG standard is good enough) --> bass will improve a lot, resolution also improve a lot and it become more transparent and musical.

B) twist the internal cable connect poweramp to the connector port for speaker --> improve a bit the imaging & resolution.

C) Change the OPAMP to a better 1.

D)
10000uf capasitor --> low cost is to pararell a 0.47uf/50v blackgate nx-hi-q --> the HF will be much smoother but sound characterisc is still the same

Change 10000uf cap to 10pcs of 1000uF or 5pcs 0f 2200uf cap --> u can select type of sound u want and the bass is definitely better than 1 pcs of 10000uF cap. (this is expensive mod unless u like your 8000S very much if not no need to spend on this)

E) Change the evok film cap especially the 0.1uf in between the 2 pcs og 10000uf e-cap to a better cap --minimum u need to change to ERO MKP1837

F) If u wish to further improve the resolution u can change all the evok (white colour) cap to a better 1 e.g ERO mkp and so on BUT be careful, u can further improve resolution & detail with ERO MKP cap anyway it may sound thin when resolution is too good. Unless your speaker & cdp is sound very thick & warm only u shall think of changing the evok cap to other more detail cap... i do not recommend to replace this evok cap with very expensive cap because it will be better to just DIY a tube preamp by using good cap. (Imaging a simple 5687 tube preamp only need 2 pcs of good film cap) whereas in 8000p THERE ARE >20PCS OF FILM CAP.

this the mod 8000A i done last time(refer picture).

another photo is my DIY pre amp.

Dear Sugagar,

If your OPA in 8000S is TL072, u can change it to
a) OPA 2132 (cheap <HKD50), easily to just plug in for replacement, sound similar to OPA627 only little bit different where a bit less musical than 627
b) OPA 627 - EXPENSIVE & u need to use 2 pcs (this is single channel) -

c) AD 825 - single channel, need to use 2 pcs in a special socket(browndog) - ~hkd 50/pc - i'm using this, it has better resolution & detail than OPA627 but not as warm & musical as OP 627.

so it is depend on what characteristic u wan when choose OPA.

For the 0.1uF/100v Evox cap in locate in between the 2 pcs 10000uF big tank, u need to look for some cap which the lead pin is small, size also not too big, if not hard to put it in. A lot good cap is rate with very high voltage and the lead is very big where u can't put them in. The problem of audiolab is that the hole a pcb is very small. maybe u can use evox glass casing film cap or musicap/100v or auricap 0.1uf/100v(u may need to connect thinner lead to musicap & auricap)

P/S: since audio lab pcb hole small, u may use blackgate pk series as it's size smaller than std.

Hi, Bryan,

Which country u stay? there are still a lot shop selling blackgate.

or u can buy from this website as well.

http://www.partsconnexion.com/catalog/CapacitorsElectrolytic.html

ur version shld be as photo attached , there is a ribbon cable there. it is similar but with more ecap. just replace e-cap at preamp & power suplly section if u don't use turntable.

pk is small quality as std but with smaller size so more suit/easier to be use in 8000A.

627 got 627AM(most expensive~hkd130?/pcs), 627ap(~hkd70), 627bp(~hkd90) I'm not sure the price now. 627 it is quite musical but the bass is a bit blur for 627ap.
i myself using AD825. FOR 627 &AD825 need to use 2pcs to replace a TL072.
cheap version of 627 is BB OPA2132 (~hkd 50?)


wht cdp & speaker u r using?

No need to change the Cable, just twist them enough by pair, positive & negative as a pair (see my previous picture for the twisting)

another mod can be done is that: change the RCA female connector to a better1 and use silver cable (original is pcb mounted RCA).


With the above mod u can feel a lot different already.... then no point to further upgrade as futher upgrade take more cost and less effect....


for power amp, before you get a 8000P, u shall have a look at creek A52SE(with 2 transformer). It seems better than a 8000P which had moded with BG cap. So 1 of my friend is sell off his 8000P and use creek A52SE with his 8000C preamp.

dear bryan,

if the noise happen only when touch the volume control then accphoto's suspection is high chance... if it happen when volume control not touch.. a lot possible, if old machine can be contact problem, can be e-cap aging... or grounding contact problem and so on..


dear sugargar,

l272m is different pin sequence from OPA2132 (bur brown type of dual OPA), In the market most convertor of 2 pcs 627 is to convert to pin like 2132 but not LM272M. u may have difficulty to find a correct socket for this.

Best is change all e-cap to BG as 8000S don't have phono stage. but u can leave the 470uf cap alone and change the 100uf & below to BG 1st (if not mistaken all cap at preamp is 100uf n below). i myself only use elna cerafine for the 470uf (to reduce cost)

it is better if u can attached a full picture of your 8000S, it your version is the new china made silver casing version?

circuit in the box is sensitive to RF thus the purpose of the metal case is to provide isolation to reduce interfence inside the box.

when change cap, should use same uf, but voltgae can be same or greater. e.g chnage 4.7/35v to 4.7uf/50v is ok.

check your cap whetehr got arrow/line indicate the neagative pole? see pic ture of BG Std the gold arrow/line indicate neagtive pole. most non polar cap will have non-polar word on the cap n they don't have the arrow/line.

dear sugargar,

OPA2134 can be repalced by 2pcs OPA627 (opa627AM=metal case is the best)

understand Elna silmic CE-BP is bi-boplar (non polarization), so if u can find the negative mark then this cerafine BP is high posible is bi-polar type too.. i understand from elna their BD version alos bi-polar -->B normally stand for bi-polar...
so to play save u can use BG N series for replacement of this 100uf cap.

as long as the pin location is the same as OPA 2134 and the voltage supply is >15Vpeak (or >30v rail to rail) should be ok to be use.

I can't advise u on the sound of LM 4562 as i do not have this chip to test on.... sorry...

i only had test on 627AP, opa 227, opa 2132, TL 082, AD 825, opa 827, OPA 2604 only....

Hi Bryan,

Till date what type of component u had change?
Can share with us the sound changes of ech component?

If u r running in the component such as capacitor, resistor & IC, i don't think the volume level will make any obvious differences excpet if u wre run in a speaker than volume leve and type of song/music may play more roll.

fro running in component i personally feel that the discrete run in method may be more effective than continuos run in. E.g (1hr+1hr+1hr )--> total 3hrs but with interval maybe more effective than continous 3hour especially for capacitor. As during interval, the equipment is off and the cap can full discharge then when on again it will charge from zero to full.

Dear Sugargar,

yes, u need 2pcs of 0.47nx-hi Q since u got 2 pcs 10000uf big tank.
Then u will get smoother sound.

Dear michael,

Can you share with us the sound differences between LM and BB OPA?

What's the cost of LM4562?

the warm vocal shld be due to the jensen resevoir, you use jensed gold 2pole or black 4pole?

blackgate will make the system more musical and transparent with good bass the resolution will increase a bit. But this cap really take time to run in!!!

If u 12 increase somemore on resolution then need to replace the evox film cap, the risk is it may reduce the warm/thickness so not necessary do that. But the 0.1uf evok film cap in between the 2 reservoir must be change (this cap really play role).

your 827 is AD 827 or BB OPA 827?

jensen gold 2 pole have warmer sound but softer bass... those vocal lover will prefer the gold.

I'm using AD825sound shld be similar to your AD827.

without internal separation will use the preamp in (but my tube preamp volume need to raise till 3'o clock"

if use internal separation then use power in, then with 9 o'clock volum is very loud already but my old old version 8000A have problem where the preamp will become very microphonic..any knock/vibration will transfer from preamp to the speaker (in brief my tube preamp become like a microphone)...

so what i do is use the "preamp in" without internal separation but i change the internal resistor value so that my tube preamp don't need to raise till 3'o clock.....

i personally feel that 8000A's preamp section is better than its power section. Since u had modify so much on 8000A(especially preamp section), u shall use it as a preamp and look for a nice power amp in future upgrade.

If u 12 have soem tube sound just DIY a good tube buffer. the cost to DIY a tube buffer is much lower than DIY atube preamp as u do not need a volume control on buffer.

A lot people tends to select 8000P as power amp when use 8000A as pream... but i'm not so keen on this as i feel that there are plenty of power amp outside can do better job than 8000P.

E.g quad 606 power amp, creek A 52 SE and so on.

i have a friend is using 8000A with Quad 606 and a 5687 tube buffer, another 1 using creek A52SE (he sold his 8000P-mod with blackgate after tested on A52SE)...

Quad 606 is 140W/channel into 8 ohm...

it can push ProAc 1sc (84dB) easily... so i can't see any problem for it to push 3/5A.

606's sound is more refine than 8000P imo, for solid stte amp consider nice vocal..very good control....

2nd hand price ~hkd4500

For 2nd amp u may look at teh shop of website... HK shld have a lot place to get 2nd part....since i'm not in HK i'm not so familiar...

my friend buy in from singapore (through echoloff web)

for matching--> input impedance of the power amp.....u need to plug in the tube preamp into the poweram then only can know it is really matching or not.....

If not mistaken, 606 got several version, older version using EI transformer, newer version use toroidal transformer..

I believe the inverting & non inverting u r mentioning is refer to the inverting signal & non inverting signal. The iC/opa can act as diffrential amplifier or comparator. Some circuit will use non-iverting signal and the phase of input signal and otput signal after amplification is at same phase.

Inverting circuit is opposite, input signal is 180 degree different with output signal.

So the inerting & non-inverting is the method they use to amplify the signal only.... u can search though the the internet on "voltage comparator" & differential amplifier" to understand more on how the IC(OPA and so on) working with the signal..

so far no problem on matching 8000A with quad 606. But to match tube preamp with Quad 606 you really need to test it out.

E.g. the tube preamp i make can use with 8000A with no/un-audible hum but when use with Quad 606 the hum is obvious.

No exp in 909, believe that 909 shld be a better 1 but the 2nd price shld be much higher.

Wow.. u really fast action, how much u bought the 606?

606 have much better control on the bass and sound comfortable, even at very low volume, it can still give nice detail. Not like audiolab need to raise to certain level then only the real sound coming out.

And u can feel that Quad 606 play music easily, audiolab is like struggling... no choice the pwer ration is a lot difference. For moderate cost 2nd solid state amp, Quad is 1 of the good choice. Another choice is Restek tensor (200w) but more expensive and it maybe not as warm as quad which shld be pair with tube preamp.


If u intent to keep the 8000A as pream, later upgrade is to DIY or get a tube buffer to place in between your CDP & 8000A... then u will have tube feel, better resolution, sweet and powerful system.

In case u r DIY/getting any tube buffer here's some sharing, it is only my personal view.

1) 5687 tube --> very good resolution, tube feeling is moderate
2) 5670 /2C51 --> more tube feel but less resolution
2) 12AU7--> very nice tube feeling, HF & mid is really sweet but bass seems a bit less.

In case u DIY a tube buffer, my advise is that the cathode bias cap must use at least blackgate std better if can afford N series. For signal coupling, moderate cost cap is mundorf Zn, higher is jensen cu, my ultimate choice is Vcap teflon..

In fact  i had DIY a 5687 tube preamp for my friend, when use it to the quad, it actually give better resolution, sweeter sound compare to 8000A but bass not so strong. Anyway the 5687 tube preamp have obvious hum when use with Quad 606 which i need to solve this problem. So temporary he use this tube preamp as a buffer....

ALC,

Change power transformer??
Very expensive oh.......

Bryan,

Just ask people here DIY 1 for u ~ HK1000 can be done for a single tube 5687 buffer, since tube buffer don need volume pot.

6BC4 is single channel, it is diffrent pin from 5687 so can't plug in straight away.

No schematic and never try it so only can bse on picture to comment.

1) the casing look nice...
2) it use toroidal transformer--> if this toroidal trans is not special made/of very good quality it may even worse sound than EI transformer. Tube stuffs easier to get good sound from EI trans unless the toroidal/R core type is speciall made for tube...
3) it use solid state retifier--> don't expect the imaging & sound tage to be very good, i prefer tube rectifier which give better imaging, sound stage...
4) the ecap is so so...u may need to upgrade later
5) PIO is warm sound--> but it depend on build quality
6) Iron case not as good as aluminium case
7) pcb is not as good sound as direct connection...
6) If u can DIY, with usd250 u can build a better 1...


i wish to post u some schematic of 5687 but this few days my server got some problem... if wisg fats response can just email to me sswong@healthtronics.com.my

so i guess the sound of this 6bc4 buffer is warm sound with tube feel but lack of sound stage & imaging, it may sound like compact to the centre.

Anyway i might be wrong....

Bryan,

Here's some schematic

the cathode follower is no gain buffer.

the other is tube preamp but u can made them as buffer, just replace the volume pot with 2 resistor (47k -from input to grid & 10k to ground)

Hi bryan,

The 5687 i mad efor friend is simlar to this attchmnet AN-M7, it is a preamp which have gain and it use less film cap thus easier to obtain decent sound with low cost.

the 5687 cathode follower is no gain.

Modi sir in hififever had a very good diy an-m7 5687 preamp, so u can actually ask him to DIY 1 for u but without the volume pot (save cost) as u use it as buffer, latter u can juat add a volume pot to use it as preamp if u like.


For transformer if u got budget can use good 1 like SAC silk (~hkd600+) or like me temporary use a cheap 1 ~hkd100+... the cap u can use a good 1 like jensen cu, intead of 0.1uf, i prefer to use 0.22 or 0.33, jensen cap now got offer in below web. http://www.partsconnexion.com/catalog/CapacitorsFilm.html

the aluminium casing , here got 1 source, the AL314 is big enough for tube buffer or preamp
http://www.vt4c.com/shop/program/main.php?cat_id=1032&group_id=2

http://www.partsconnexion.com/catalog/CapacitorsFilm.html


cathode bias cap can use blackgate N series 220uf/6.3v of standard 220uf/16v depend on your budget.

If ur budget is tight, i will suggest u to spend on the good cap & resistor (so that don't need to upgrade anymore on this)and use old casing (frm VCD/DVD player) & cheap transformer, next ugrade only change to good
transformer and nice casing...

Other than Modi, i believe autumleavecat and alfcat can also DIY this simple buffer.... i saw somebody selling this 5687 preamp here but seems those who buy from him have bad comment on his after sale service and his preamp claim to have hum...

another alternative is that u just get your hand in for your 1st DIY project it is not so difficult. there are a lot infor from website below:

1) www.diyparadise.com
2) http://yunwt.u111.net/2wenzai_pre/pre11.htm

8000A still act as preamp..... but u will have some tube sound/feeling, and slightly better clearity.....and smoother vocal.

U will able to hear the different!!!

Ha go and borrow the marrantz M7 form Alcat as use as tube buffer to test out : )

u are right! all tube preamp can be use as tube buffer.

The difference is that tube buffer without volume pot as a very good volume pot is can be quite expensive.

Yes, if your budget is ok, then get a tube preamp let u have more option to play with but ensure the volume pot in your preamp is not the loudsy 1... minimum is Alps, better is those step type. for step type u can save cost by using good resistor at the volume level u commonly use, the not commonly use level just use cheap resistor.


u can use tube buffer as preamp if your CDP have volume control...

Different tube have different sound, different brand also have different sound.... i'm quite new on tube stuffs does only have experience in popular tube like 2c51, 396A, 12AU7, 12AX7, 5687, 6N3.... some is more tube feel, some is more detail...depend on your taste...

Most important is that u must listen to it and judge whether u like it or not? As the sound i like may not be the sound u like....

For item 2) You not neccessary to use jensen, it is depend on your system now, if your system now is already too warm & sweet with very soft bass then not advise to use jensen again on power amp.  For matching we need to achieve the balance... when our cdp is very analytical, then we will try to use warmer amp to achieve the balance and so on....

for item 4) nothing much to change

there only only a few e-cap can be change, then the OPA, then 4pcs of big tank 10000uf if you wish... anyway a mod 8000P (big tank is not moded) seems not as good as a creek 52SE & Quad 606...

134 can be repalce by OPA627.
But my advise is spend to replace all the e-cap to blackgate 1st then bypass each big tank(10,000uf) with NX hi-q 0.47uf.
OPA627 is expensive and effect is not so much compare to the changes of E-cap.

then change the rectifier diode to shocky diode or ultrafast diode (farnell got some diode on clear stock price), u in which country??

the 2 small cap at pin 4&7 is connect to the ground... this cap is useful to reduce noise and some people will recommend to use 0.47uf Blackgate nx-hi-Q (as bass will be slightly better)... so i suggest you to use either 0.47NX-HI-Q or 0.47uf film cap like vishay/mkp. I also do this on my OPA and can feel the background slightly more quiet.

actually OPA134,132 and 627's sound is quite similar, but 627 is just little bit more musical....so u need to justify wheter worth to spend on this or not?? for really difference sound can try AD 825 but need socket loh as AD825 is soic.

basically schotky diode sound more smooth and analog...but the effect not so obvious compare to the change of capacitor.

for the diode, i think u shall change the 1n4002, it is rated at 100v,1A, so u can replace by shotky diode with the same or even better in higher rating. NXP, vishay also ok lah, better get TO-220 type for easier soldering.
the other 3 leg diode can temporary maintain....

for the relay, i didn't change, anyway u can try to get a compactible japanese made 1 if you want.. NEC or so on..

from the picture u give it seems there is only 1 cap use to connect between pin 4 & 7. a better way of connecting it is using 2 pcs 0.47 cap, 1 connect to pin 4 then the other end to ground, then 1 pcs connected to pin 7 then to the ground....