Aura Evolution VA100 • Clean up & upgrade

Hi there,
I've just been given an Aura integrated amp, wich was an attemp of B & W to sell electronic stuff.
I've also been given the matching CD player from Aura but it's more close to normal Philips' stuff and maybe it's just another Philips with a new shell. Anyway this CDP will also be cleaned up and some parts upgraded.
link to CDP upgrade: http://www.diyaudio.com/forums/showthread.php?s=&threadid=133264

It will be a good system to drive my Quad 11L as soon as I'll be changing speakers... maybe in many years ;)

As far as I've read about it, it has a warm sound aimed to sound like class A amps. It's said to be a good sounding stuff with interest. Also got a phono preamp (also said to be good). Update: havin' an ear vs my current integrated (G&W TW-2006X) it's well balanced and warm at low volume, but lacking of space, details and a bit harsh.

Here is the amp:
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An externally hosted image should be here but it was not working when we last tested it.
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An externally hosted image should be here but it was not working when we last tested it.

Phono input:
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Amp side:
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2x BHC 4700µF 63V,
a single NE5532 in the middle (PS part or preamp part? ALPS pot is wired near this (black coax at bottom of the pic) so maybe it's preamp?). Still one LM4562 left if I replace the CDP's BB OPA2604.
a pair of these near the inputs or maybe just the phono preamp, with Nover 220µF/40V at their side.
Loads of MKC around, after the (phono) preamp for example.

So if some of you knows this little beat tell me more!
What may be changer after all these years? It's from 1992 from the PCB.
Or factory service manual someone?

Thanks,
Matthieu
 
Found is thread, nice!
So the LM4562 there will do wonders. The PS line's caps may be upgraded there, do the big 4700 BHC caps deserve to be upgraded?
Any good choice instead of the 5534 at the phono preamp? The single LM4562 wich exists or not?
The sound here should stay warm for it will be a second background music system, if that helps in the choice of caps or such.
Thanks!
 
If you replace the 2sj162 with Buz906dp and 2sk1058 with Buz901dp
this will increase the output current dramatically

you will need to increase the bius current slightly.

the next week link is the transformer,B and W used the cheapest toridal at the time and not one for good performance.

i Have a concerned about that opamp in the middle, what is doing as the VA40 did not use one and many people have reported that the VA 100 did not sound as good as the VA40.
No line buffer is needed to drive the power amplifier inputs.
so this will help make the amplifier sound Harsh along with to much negative feed back (making the amplifier over damped)
:smash:
 
Hi Andy,
replace the 2sj162 with Buz906dp and 2sk1058 with Buz901dp
I won't go that far for now or maybe ever as it's not my main system and I just want to " release " the sound, and what you said is really what I feel comparing this to my main integrated, " a bit harsh and damped ".
Will have a fast try with the LM4562 as it's been said to do wonders as an preamp.

If any way to simplify that stuff and remove parts as it seems that preamp/buffer part can be taken away please let me know, and let me know how to do.

Thanks guys!
 
:Popworm: Eek, ITL was B&W owned ?
 

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Cross threads...
Maybe I can get rid of the Muse and fit them in the amp for the same job, why havin' 2 times these boring caps?! Once in amp is enough no? Or spend few euros for a real cap there, a film cap like an ClarityCap or such?... I'm asking that again in the amp thread.
Amp has 2x Rubycon NA non polar just after the potentiometer...

Also don't know what to do for those little thingy of Elgen 220µF/35V, seems to supply the opamp.
The 15 year old BHC should be changed or not?
I'll take pics of the pcb when I'll fit the LM4562.

Matthieu
 
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Joined 2006
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Malefoda said:
Cross threads...


Also don't know what to do for those little thingy of Elgen 220µF/35V, seems to supply the opamp.
The 15 year old BHC should be changed or not?
I'll take pics of the pcb when I'll fit the LM4562.

Hi Matthieu

I replaced the stock smoothing caps in my 30 years old power amp with some 15000uF Mundorf and the result was very good. (Much more speed and control..... better high freq detail).

On the opamp you can also use Rubycon ZA instead of BG.

Ricardo
 
Good Ricardo,
I'll have to take the PCB appart and check under what does what before choose. I may fit the LM4562 and new cap if any at the same time.

Right now the problem is to find some cap quite not high to keep the slim lid closed clean.
I also want to keep the sound warm ans soft.
Right now the same BHC ALC10 but 6800/63 instead of 4700/63 will fit, they're 35mm high both and 35mm of diameter for the 6800 and 30mm for the 4700. And capacity is more, don't know if it can do bad or good... or maybe same capacity but bigger for better specs?

I'll be back with pics.
 
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Joined 2006
Paid Member
Malefoda said:

Right now the same BHC ALC10 but 6800/63 instead of 4700/63 will fit, they're 35mm high both and 35mm of diameter for the 6800 and 30mm for the 4700. And capacity is more, don't know if it can do bad or good... or maybe same capacity but bigger for better specs?

The bigger the better as long as you do not go over 22000uF... after that you might need to bypass the smoothers.
 
Here we go for latest news and questions...
As you will see on pics I've removed the second outputs, it's a simple Y connection so it's useless. Maybe was acting a bit as an antenna... LM4562 is in, 0.47 MKS Wima between 4&8.
On a pic you will see both BHC caps had contact with the aluminium radiator frame (one transistor also... moved it up...), it's burn on both pins on one cap and on one pin the other. Are they degraded? It's working fine but has been given to me as sometimes making noises on one channel. Maybe this contact ;)

• If really needed or a big upgrade, what if I go for the BHC (the only ones fitting well the lid as far as i've found) 6800/63 instead of the 4700/63? I've read (my Acram thread) that it can harm the sound in some ways, is it true? Also I've seen all other guys modded this jumped to 6800 ans sticked to it so I think in that case it' all good.
Where to buy BHC ALC10 caps 6800/63 online? Can't find them at all :'(

• The ALPS pot feeds 2x MKT 0.470µF, I think I'll have good gain by fitting something more serious as a ClarityCap or such, bigger capacity like few µF? Size will be a concern here again. I'll go for multiple brand of caps maybe PX and SA.

• The small caps non polar (were Rubycon NA 100/16) has been changed for the removed Muse 100/16 from the CDP, they're far bigger.

• Still have the Elgen 220/35, what do you advise there?

• Any tips to screw back the transistors to radiator? May I remove the kind of sheet between and put some Arctic Silver III (got some, mac overclocker inside) ?

There are the pics, last one is flipped in order to let you match stuff and circuit. In fact it dusturbs me more than makes me easier... Hope it's ok for you!

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.



Thanks for helping fellas!
Matthieu