Muting transistors

[Assyst1606]

I going to replace the existing RCA connectors with a better ones using solid core copper wire for the connection. Hopefully that will improve the sound a bit.

[anatech]

Hi Assyst1606,

Hopefully that will improve the sound a bit.

Why on earth should this change help, unless the original ones have a problem? Sorry, just being realistic here.

The M5204P is in the audio path. You do need to find the data sheet on this so we can see what exactly is going on. I had a quick look with no luck. You should make a search or buy the proper service manual for this model. Some IC information will be in that manual. The in's and out's at the very least.

-Chris
Edit: Found this :

M5204P
Dual-Channel Audio Preamp-Input Amplifier

AV (dB) Min.=5.5
THD Max. (%)=.05
Quies. Pwr (W)=1
Nom. Supp (V)=5�
Package=DIP
Pins=20

... on the Datasheet Archive site. You can also try Mitsubishi or Renesas for device data on this IC.

[triode_al]

I am tweaking a CDP-590 which is similar in output, has PCM56P and this M5404P output chip.
It also feeds the headphones from the same signal! And it has this mute/reset signal input. Not too comforting.

So my thoughts are to:
1) passify the PCM58 (i.e. a resistor output)
2) have a discrete amplifier stage and not use this chip. This chip might use CMOS signal switching to mute.

The unit looks well made.

But the power supplies are not separated, so I also think on adding a DAC-stage only PS, plus one for an output stage.

AND of course a TENT Clock unit to replace the stock clock (that will never give the 18 bits resolution the circuit is designed for).

I have converted another Sony to passive, CDP M69, and that has a very high richness in harmonics. I expect more here, this unit seems better.

On to the soldering iron!

Triode_al

[triode_al]

At this moment I am working on such a sony CDP 590, similar in board like posted in this thread..
I have inserted a tube buffer , hybrid, PCC88 plus emitter follower based on a BF258. Works great, bandwidth over 500 kHz.
Passive input around about 200 ohm.

I want to be able to take the signal back through the filter, switchable.
The PCM56 outputted normally to pin 9, this goes to pin 10 (L) and 11 (R).
This will give a smoothening of the output.
As well it will restore the headphone output.

When I passified the PCM56:
- I cut the traces of pin 9 of each D/A chip, floated pin 10 and earthed pin 11 I took the resistor for passive I/V from pin 13.
The trace from pin 9 went to the P5402 pin 10 (L) and 11 (R). This IC apparently has 4 opamps, two for the signal filtering and two for the headphone.
albert