SONY CDP 557ESD (707ESD) sound shaping

[phixphi]

Hi all!

I have a CDP 557ESD. It sounds...well, in general horrible (I listen through Stax 717 + O2MkI). If there are more than 3 instruments the output is a complete bordello, a total mess, all female voices sound like vipers, etc,etc.
But, I feel the it has some potential, so I try modding it.
The first thing to go is Guido's clock with a dedicated PSU.
Then has anybody sucessfully tried:

1) Ignoring deglitching/lowpass/buffer crap and connecting a passive (R or trafo) I/V, followed by a decent (tube) output directly to the pin 35 of PCM64? Will try to cut the relevant part of the schematics and post it for completeness. PCM64 has +/- 1mA out.

2) Putting it into NON-OS but without completely bypassing CXD1144?

Any hints on the baove questions welcome
Can provide the datasheets on CXD1144 and PCM64 if needed.
Cheers,
jk

 

[phixphi]

Just to answer my own question it looks from the datasheets
like CXD1144 has no Non-OS mode unless I'm wrong.
So probably bypassing is the only way. But will CXD1305 and PCM64 be happy
with the data directly from CXD1125? Datasheets of CXD1305 anyone?
Cheers,
jk

 

[rascal101]

The PCM64 is an 18bit parallel input DAC (probably using segmented architecture like the PCM53 ... maybe). This type of DACs are very rare. Compared to serial input DACs you have faster conversion time and higher monotonic performance. Maybe better THD+N too. I think it is better to make changes on the output coupling capacitor like the one proposed by Walt Jung in his picking capacitors paper.

 

[Mikewong]

Any practical suggestion of tubes output including schematic for this player?

 

[coolhead]

Have a look at this SONY CDP-557ESD
He bypass the PCM64 and use external DAC, I think is a good reference.

 

[PlasticIsGood]

Sony didn't generally waste 190A mechs on trash players. If it is distorting so badly, perhaps repair would be more appropriate than modification? At least as a first step, you might check out the audio stage and perhaps recap, just to give you an idea of how the player sounded originally. Then you will be able to hear properly any subsequent modifications.

5532 opamps might not suit your taste, so you could change them next without spending a lot of money.

Clean the delicious mechanics and lubricate carefully with plastic-safe grease and oil, as appropriate.

By then your attitude may have mellowed. It's an historic machine, and deserves some respect.