Aura CDP • Clean up & upgrade

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Malefoda

Malefoda

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Joined 2006
rx7france.com
#1
like I said about my new amp: ( http://www.diyaudio.com/forums/showthread.php?s=&threadid=133265 )
I've just been given an Aura integrated amp, wich was a 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.
Click to expand...

There are the pics:
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.

Output:
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DAC under PCB:
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So a CDM 9.65 mech with dead gear, BB OPA2604 with Nich Muse at their side. Another AOP near the PSU, a simple JRC4560.
Under the PCB is a SAA7321GP.
Anyone recognize a Philips CDP with has been upgraded with good result?
After havin my amp up I'll use the left parts here, maybe I'll have some LM4562 left, some caps...
Any toughts? Someone with schematic?

Thanks,
Matthieu
 
#3
Hi Andy,
no it's in full working condition but the tray gear (not a prob anyway).
I'll go for free upgrade right now, not much even for it will be a bedroom, living room or even garage as I already have my budget system but well modded (even if the CDP still has its LM4562... another story). Maybe put no more used parts from my Marantz CD53 in this (as caps, regs or such...)
Bye bye AOP2604 and welome LM4562, bye bye muting transistors.
I haven't seen where the Muse are used, maye on the PS lines of the opamps? No DC blocking caps?
I don't know how sounds BB OPA2604 beside LM4562 but it will be an easy upgrade for sure. Have to find some Philips CDi infos seems!
Will tell ya!
 
#5
Ok I'll have a look, maybe take them away... integrated should have a DC blocking system anyway? I wonder how much DC offset I can allow at the CDP output... I need bass!
I have 3 VibraPod feet around, maybe sell them on eBay and get good caps instead, not sure feet is right now the way to go 🙂
 
#8
You need to measure DC offset via a low pass filter, say 10k + 1 mfd connected directly to the output sockets. There could be to much hash to get a reliable DVM reading without.
OPA2604 are excellent sonically.
 
#10
Mooly said:
You need to measure DC offset via a low pass filter, say 10k + 1 mfd connected directly to the output sockets. There could be to much hash to get a reliable DVM reading without.
OPA2604 are excellent sonically.
Click to expand...

I'm not an expert but I guess this is when remove the DC blocking caps, I'll try that thanks!
Any opinions to the LM4562 vs OPA2604 sound?
 
#12
I use the OPA2604 ( OPA604 Single ) and find them the most musically pleasing to my ears. Haven't tried the LM4562.
When measuring DC offset you have to measure using the output ground as a ref point. Easiest way is to measure at the end of your cable plugged into the output. Connect a 10k ( anything from 1 k to 47 k and a 1 mfd or thereabouts cap to ground ) and measure DC millivolts across the cap.
 
#13
Well well,
As I liked the LM4562 more than any other in My CDP I think I'll go for them. Have an ear before/after anyway.
Are some 100nF MKT caps ok to bypass big PSU electrolytic caps? I've used 100nF PPS in my CD53. If with 100nF MKT it's better than with nothing I'll go for it!
 
#18
If you may help me to choose the right caps, they must be cheap, it's not my main system, just want to refresh it for a good price (close to 0 amap !). Oscon/FC are exepensive? Or FC all the way even in digital? If the sound change on some caps then let them alone. If it's useless until I go for it tell me so I just go for LM4562 and fast rectifiers.
Around de DAC:
7x Nichicon VX (coffe machine stuff?) 33µF/16V,
and 4 more here and there.

other big cans:
2x Panasonic SU 470/16
1x Pana SU 3300/16
2x Pana SU 1000/16
1x Pana SU 220/63V
1x Nichi VX 2.2/50V

One per opamps at pin 5 is a Nichi VX 100/10V
and in signal the Muse 100/16V.

I still have 2x 470/10V Elna RJH, good on analog parts.

What where?
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...

Thanks,
Matthieu
 
#19
Think you will find changing the OpAmps give the biggest differences.
The only way too tell is to listen long and carefully after each change.
To be honest, my opinion is that just changing PSU caps for different types will not give any audible change. Local decoupling at critical points can be beneficial, like the caps on the OpAmp supply pins etc but differences are tiny -- more wishful thinking more often than not.
 
#20
That's a good advice. The only thing I find strange is... I can't find any caps on supply pins of the opamps! Or they are far away near the rectifiers and regs... have a look.
I think I'll stick to my first idea, just grant this stuff (CDP and amp) with spare or upgraded parts of my loved system. No way for this to face my Marantz 😉
 
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