Playstation as CD-player

[DragonMaster]

OK so here's the output stage scheme of the 1001.

VT2 is what controls the muting transistors.

The only difference with the RCA jack compared to the A/V MULTI OUT is that there is an opamp. The schematic after the opamp's output is an exact copy of the a/v out scheme. I'm just not sure about the small caps directly @ the output connecting to ground.


Anyone here with a model without RCA jacks, is there only one pair of caps after the DAC? There is no opamp also. Am I right?

[Mick_F]

Good work, Dragonmaster!

Mick

[DragonMaster]

Good work, Dragonmaster!

Thanks!

Maybe your fried board just has a dead transistor or opamp. Have you tried the AV out?

With a stock board, I think that the A/V OUT is the best : The signal passes thru only one cap while the RCA jacks pass thru a chapo opamp and two caps. The traces are as tiny for both. The only advantage with the RCA jacks for now is the interconnects. The AV wire made by Sony seems pretty thin, but it's one of the best console A/V wire I know.(It didn't break, I broke two Nintendo cables in the same peroid of time)

[Mick_F]

No, I didnt try the AV out, but it is a good idea. I will.

First I have to retrace all the research you did on the output stage....

Mick

[DragonMaster]

First I have to retrace all the research you did on the output stage...

A diode checker or ohmmeter will be your best friend. You will also need to be able to see what's on the PCB easily.

If you don't have the AV cable, you can use the test points as there are a lot of them.

[back]

Originally posted by DragonMaster
.


Anyone here with a model without RCA jacks, is there only one pair of caps after the DAC? There is no opamp also. Am I right?

mick f `s sheme is correct for mine (5502) but it`s not the same for all models the 75xx 95xx and ps one don`t have opamps at all.

i guess opamps are good because the german guys say the older the better sounding.

the thing is that mine sounds fantastic after i shorted the caps.

i use good quality rca and i soldered them to the AV out pins.

another thing that gave me a good improvement was a power cable soldered directly to the psu at the power socket pins.

[DragonMaster]

mick f `s sheme is correct for mine (5502)

Mine or the one Mick posted which comes from here:
http://www.methe-family.de/cd.htm

i guess opamps are good because the german guys say the older the better sounding.

Well that's what everybody tell but an ordinary JRC opamp is not the greatest I think.

A thing to try would be a classic PSU. What I think about is to put the regulators on a custom PCB that fits where the current one is and use somethign like a 9-12VDC wall-wart. This way, we keep the AC away and we only need a two-wire cable.

Also, the layout could be done so that we keep the current PSU switches. It will prevent us from having to select different ones.

[jives11]

Originally posted by DragonMaster
The DAC output is connected to both. I checked with my dmm. You can see it too.

I'm currently checking while writing. What I can see is that there is a non-amplified circuit to the A/V jack and a circuit using an opamp to the RCA jacks. These all start by a cap and are connected in parallel from the DAC outputs.

I'm checking while writing and the first pair is going directly to the opamp. Also, the third pair of caps is connected thru some resistors to the RCA jacks.

The second pair is
cap output going to
100 ohm to ground in parallel to 1k ohm going to
100 ohm to A/V jack in parallel with transistor

The circuit of the second pair is the one from the scheme here:
http://www.diyaudio.com/forums/showt...749#post774749

The circuit is not pretty interesting for us with the 100x ones as we are using the opamp circuit. At the same time, there are muting transistors also there.


If anyone wants, I can compare the A/V out with the RCA output as I have the A/V cable.

So: mods to try, disconnect the second pair of caps as it's unused, and short the first and third pairs of caps.

I can try to come with a scheme if people want.

So Dragonmaster, for users of the 1002, are you saying that to short 423 or 424 we must connect a wire from the +ve of the 1st capacitor to the -ve of the 3rd capacitor dans la avenue de la farad.

Why do they have 3 caps representing one on the circuit diagram ? Is it just a size thing ?

[DragonMaster]

Why do they have 3 caps representing one on the circuit diagram ? Is it just a size thing ?

Because there are 3 different caps on the scheme. The circuit provided by MickF is for a newer version of the PSX that doesn't have the RCA jacks.

There are two independant circuit. If you want to remove all caps from the RCA jacks circuit, short the first and third pair. The first pair is before the opamp and the third is after the opamp. If you want to make the circuit like the A/V MULTI OUT, connect the input of the first cap to the output of the third.

The second pair is just for the unamplified A/V MULTI OUT.


I compared A/V MULTI OUT and the RCA jacks and A/V OUT seems to sound a bit better. It's unamplified, but the gain is the same as the amplified RCA outputs.

[back]

Originally posted by DragonMaster

Mine or the one Mick posted which comes from here:
http://www.methe-family.de/cd.htm


Well that's what everybody tell but an ordinary JRC opamp is not the greatest I think.

A thing to try would be a classic PSU. What I think about is to put the regulators on a custom PCB that fits where the current one is and use somethign like a 9-12VDC wall-wart. This way, we keep the AC away and we only need a two-wire cable.

Also, the layout could be done so that we keep the current PSU switches. It will prevent us from having to select different ones.

i mean the jrc maybe better than nothing.

about the psu i think that a wall wart is not enough 17w is 1.5A
i was thinking 3A minimum to have the best we can get.

anybody knows how we could have spdif output for use with an external DAC?