remove output cap's

[Marcelinho]

As newbe I monitored the threads for cdp tweaks.
I decided to try them all to satisfy my curiousity. I'm willing to tweak my sony x-202ES to death doing so.

Best tweaks sofar:
disabling the variable output.
replacing 100uF el output-cap with 10uF MKT.

Upgrading PSU with better components, Netfilter, shielded mains-cable, removing mute-transistors, changing opamp NE5332 for LT1364, didn't bring much improvement (checked if possible with left right comparison).

A clock upgrade gave me some problems with RF/HF within the housing. With the top removed it works fine. Maybe a seperate PSU will solve this

With all tweaks in place, it's almost as good as a unmodified cd80.
It lack's the punch in the bass (not to confuse with the booming undetailed bas from a cheap output cap).

Trying to get more punch if outputcap is to be removed
The word "on the street" is that with a few milivolt on the output the output cap can be removed or that with newer (better) opamps the outputcap can be removed. in both cases the few milivolts are very audible (as distortions in bass frequencies).

Are these recommondations BS or am i missing something?

[AndrewT]

Hi,
if you have a DC blocking cap at the input of your preamp then there is no problem with removing the output cap from the CDP.
the DC offset will still be there and the CDP will not see any difference and so will perform exactly the same.

However the preamp may not have a DC blocker and could feed a DC offset into the pre and/or volume attenuator.
Audio pots do not like a DC current running through them unless that part of their performance is evaluated at design stage.

Certainly amplification of DC offset will interfere with all following stages and may be innocuous or terrible!

By the way, 100uF output cap is enormous. Suitable for driving 600ohms inputs but I would guess that the output stage could get nowhere near as much current into this low a load. 10uF sounds about right for any following stage down to about 2k2 but better if above 10k input load. MKT is not the best choice, MFP or MKP would be better but at this size may be too expensive, how about 1uF MFP in parallel to assess the effect on sound quality.

[Marcelinho]

Hi Andrew,

I was cramped for space. The MKT was the smallest quality cap available. Your right that adding a MKP of 1uF could enhance sound quality further. I think the upper frequencies would bennefit most.
Any thoughts about the myth of newer/better opamps in regard with dc offset.

[diyman]

I tried that with a 10uF metallised polyester from Vishay. Details improved but bass thinned out a bit. I didn't like the outcome.

ckt