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Old 10th February 2012, 07:49 AM   #11
Kei is offline Kei  Wales
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Quote:
Originally Posted by carlmart View Post
Hi Kei,

If I'm not wrong it was me who suggested several parts upgrades in your Luxman.

Then I'm sorry you were not satisfied with the results.

All those things I suggested, some separately some together, were applied on other amps, including a Luxman.

You do need good speakers to feel differences, and by that I don't necessarily mean improvements. And good speakers do not necessarily mean expensive ones either.

If I recall I also suggested to completely bypass the tone control and lots of switches between the line amp and the power amp stage. That is something which proved very effective on the very first amp of mine that I modified, which did have tone controls and all that.

At least I'm glad the RIAA upgrades improved things a little.

Cheers
I'd guessed it might have been the same person. I've not been dissatisfied with the end result of the changes. It has not been any trouble as there have been improvements which was the whole point. I was a little bit disappointed that changing out the input electrolytics for film didn't yield anything significant but it wasn't the end of the world. I've kept all the components and i'll be using them again in a build from scratch. (once i work out what to build) Taking the tone control out would certainly be easier that separating the power supplies. I'll admit that i never finished changing the components, but that is mainly due to the fact the polystyrene caps still haven't shown up from the supplier yet. The speakers i use a fairly good, though no doubt i could make some improvements. I asked for advice about it in the multi-way section on here and got no replies.

I wasn't knocking your advice earlier in the thread though (although it might have come across like it, sorry if it did). Just trying to save the OP some money. Giving him the changes that should have the greatest audible effect since he is trying to make these changes on a minimal budget.
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Old 10th February 2012, 09:20 AM   #12
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It's alright. These things I recommend try to be a honest contribution.

They are things that I could testify improved many systems I upgraded, mine or on friends of mine.

Eliminating stages, mainly those that involve tone stages and switches, are usually the ones that work most marvels.

What speakers are yours?
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Old 10th February 2012, 10:15 AM   #13
Kei is offline Kei  Wales
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Vintage goodmans minister cabinets with Kef B200 (SP1063) 8" drivers and seas prestige HF22TF 3/4" tweeters. This was the thread i posted about it. (before we derail Fulci's thread)
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Old 23rd February 2012, 03:15 PM   #14
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There is an op-amp which I believe is the power regulator, it's a TL072CP. Do you think if I could get any improvement replacing this? Which others could I try?

I will be on vacations next month, so I will start modding the amp late March, early April. I will post with pictures all the steps as gradually made.
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Old 29th February 2012, 11:30 AM   #15
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Ok, the Op-Amp is in the power amp section, thinking of replacing it with an OPA2132, NE5532 or a LME49880 (with an adapter). What do you think?

Are there better alternatives that could fit and not as expensive as an OPA627 or an ADA4627.

Last edited by Fulci; 29th February 2012 at 11:38 AM.
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Old 1st March 2012, 03:44 PM   #16
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Actually, the TL072 is a DC Servo, so no need to replace, there won't be much of an improvement, it's working fine as it is, I guess...
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Old 18th June 2012, 11:27 AM   #17
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Ok, so I replaced the ELNA 10.000uF caps for some Kendeil 10.000uF 50v (same value, very cheap, couldn't refuse, and was kind of afraid that a higher spec would make turn out to become slower). It's was a pain to desolder the older ones, so I had to cut the old cap's tips...

The sound is so much more dynamic, much much more bass and more defined. Now you can actually feel the bass drum kicking and the attack on the bass notes. The bass in Pink Floyds "Welcome to the Machine" and all the analogue synths sound beautifully, you can feel all the filters opening up.

The highs are also higher. But they feel dirtier, more grainy. This could be from two reasons, I'm hoping: either it has always been like this and I only noticed now because I now have a higher extent in the extremes, and with more definition, also all the defects from the sources and the recordings are much more noticed; second reason is maybe because it's still burning in. It's been a week, so I'll give a little more time.

The other thing is that the mids are not as liquid or warm as they used to be. I figure that before all I had was mids, and now with a bigger spectrum on the frequencies, maybe it's just more even and natural, so there is less emphasis on this part of the sound.

But all in all I am very pleased with my exchange and the amp became so much better.

Next step is to change the small ELNA STARGETs for SILMIC II... Maybe next month...


One more question: I have a pair of ClarityCap ESA 3,9uF I'm taking from my DAC. Can I use this as bypass cap on the Kendeils, or are they too much?
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Old 23rd July 2014, 09:37 PM   #18
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Default Audiolab 8000A - Recap advice

Hi,

am novice to this community but am interested in revamping my old, yet still operational, 8000A amp, purchased in 1989!

Great amp but I feel the dynamics have degraded over time with components aging, am thinking capacitors.

Can anyone please advise where I can obtain a service manual and some helpful advice / guidance of the various modifications, in particular those which are the big hitters that bring the music back to life.

Thanks
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Old 4th February 2015, 01:22 PM   #19
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Default 8000A component modification

I made some modification in my audiolab 8000A amp.
The current source/sink rtansistors are replaced in Line/Tone stage, and at the input section of Power amp.
To be used four position J5xx-series current regulator diode, this pin compatible with original BC550 and BC546 To-92 transistors cases.
The balance of instruments not change anymore if crank up the volume knob.
Dramatic improvement in bass and midbass, better separation and faster above region.

Robert
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Old 6th February 2015, 07:12 PM   #20
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half of those remarks will work inside an 8000 a

--Space is limited especially for separated psu
--Most of these suggestions come from people that seen the schematic but never worked with them
--Most of the people like to use exotic capacitors which cannot be found in a proper voltage resulting that A) polarity out of the blue becomes very very important and B) huge size parts become microphonic and "pick up "" things" on the way from other stages or power supply or the opposite inject some of their problems in other stages again because of physical size and proximity Upgrades like that usually end up to a catastrophe called oscillation often perceived by hi end gurus as very crisp high my *** .
In reality ....

---Fatal for this amplifier is the bias depending on the country you live try to see if possible to measure bias versus room temperature ( if you manage to ever understand how the bias is set ) Calculate or use external sources to alter room temperature then see what will happen Depending on the result post back here to get more help on that .

To my understanding the use of parts with extreme physical size is out of the question Some electrolytic might be replaced with polypropylene or so since some of them can be found in 5mm pitch and 63v rating ( i think the max value you will ever get is 3.3uf)

Twisting cables hmm why not keep ground outside of the twist though but don't expect much to change cause of that or use of silver OFC copper or any other cable from planet zector

22.000 uf ??? no room for a thing like that .... if you look at the rectifier is a joke from ISKRA room for a bigger one ??? no f**ucking way ...

my 2 cents
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