Marantz PM310 Upgrade Project

[kapitiaudio]

For the phono stage you could also replace all those old caps with some of higher quality. There are not so many caps anyway. For the opamp, well, it's pretty hard to give any tips nowadays, so just choose any of very low distortion (OPA2134, LM4562 etc, etc, etc...). Actually you can buy a 8-pin socket and try as many opamps you wish as they don't cost too much.

For a new project I'd would use two fresh 10,000uF. These don't cost too much either.

Thanks for the suggestions. It's a good idea to add a socket in case I want to try a few alternatives, so I'll do that.

Yes you're right, I'm going to buy some new capacitors, I don't think it's worth using older ones, they deteriorate too badly.

 

[Karl vd Berg]

In the Phono stage:

C401, C402, C409 and C410, you can replace with 3.3uF film caps like WIMA as these fit easily.

C411 and C412, you can use 100uF/50V MUSE bipolar type.

R405 and R406 are 2.2k, you can replace with metal film resistors.

 

[kapitiaudio]

I managed to do a bit more mechanical work today. It's slowly taking shape.

My next job is to build a power supply for the amplifier modules.

The pieces of blank PCB I ordered seem to be taking forever to arrive...

 

[kapitiaudio]

The main power supply is in place - smoke tested, all fine. No turn-on thump at all.

I've also upgraded some of the components in the phono stage. Need to get a few more resistors as I didn't have those values.

Next step is to design the DSP board and the analog power supply board. I've already made a good start on it, some schematics to follow in due course...

 

[kapitiaudio]

The small USB input board has now been mounted at the rear. It's based upon an SA9023.

Does anybody know how far I2S will travel without problems? I need to send it 15cm across the chassis just past the small black heatsink.

Otherwise, I'll have to use the SPDIF output. I was hoping to avoid that due to the extra complexity and cost it adds to the DSP board.