Ideas on improving a Technics SL-PG100A CDP

[lauret]

Hello!

I'm new on this forum and now I'm pretty enthousiastic about improving my CD Player. A couple of years ago I build a kitamp (AKSA100) and I've had some experience in AC circuits (simple LRC circuits) on my course about powerstations.

Now I thougth about these improvements:
-Dampening the chassis
-Snipping out the muting transistors

-Replace all resistors in and around signal path with "Vishay-Dale CMF-55-143 (non-magnetic)"
-Replace C893-894 with Panasonic FC 50V22uF
-Replace LM833 with AD8066
-Putting in LM4562 in LPF section (in my model the LPF space on the PCB isn't used (bypassed), cheapest model)
-Replace c811,812 with paralleled WIMA FKP2 0,033 uF
-Same for c801-804
-Replace c805-808 with WIMA FKP2 150 pF

-Replace rectifier diodes with 11 DQ 10's
-Replace all Elco's in power supply with Panasonic FC's of same capacity, higher rating

I can buy this for about 35 euro's (50 dollars).

Now I have some questions:
-Does it matter if the values of the resistors differ from the original (example: 510R replace with 499R)?
-Are my choices of opamps good, or is this a bad combination? My sound mustn't become too clinical.
-I'm not sure I'm swapping the right components so I would ask you some feedback.

If I make this to a good end, I'm thinking to combine my expiriences into a article, with how to recognise the different components etc.

I hope you guys can help me a little bit into the right direction.

Greetings, Bart

[lauret]

I also have the schematics of the power supply.

I think that is maybe the most difficult part. The power supply to the opamp isn't symmetric: -7.8V and 8.5V. Is that a problem?

Greetings, Bart

[pilli]

...maybe it's further than you want to go, but I am just in these days playing around with discrete output stages.

A pretty easy beginning:
the "SACD enhancer" from ultranalog.com

You seem to have differential output from the DAC (a + and a -) that is summed in that "summing amp", so it applies easily.
I did it, and it makes a "wow!" difference.
And this while still keeping OpAmp-based I/V, just replaced filtering and buffering. (On a Denon 1650GR, strange Japanese edition kind of similar to the 2650... 2xAD1862 DACs per channel)

Another "wow" thing is a better clock.


To my (small) experience, OpAmp swapping did give a clear improvement, but less "wow!" than these two things above.


(My next "play around" was resistor I/V hooked up directly to a tube preamplifier in SRPP. Sounds sweet, but I didn't compare with my reference yet, to know how "wow!" it is...)