Pioneer M25 power amp bias & offset adjust ?

[jacco vermeulen]

C5 and C39 are there to dampen the diode across base-emitter of Q1.

You likely know already that the other three can go if your source doesn't contain DC.

 

[Bernhard]

C5 and C39 are there to dampen the diode across base-emitter of Q1.

You likely know already that the other three can go if your source doesn't contain DC.

Which other three can go ?

Any suggestion how to get rid of C1 C2 C38 & C5 C39 ?
The source is transformer coupled so no DC, but resistance to ground.
Which means, if i short the input caps and the adjusted input DC offset is not exactly 0V, the parallel Transformer will pull the adjustment somewhere else.
I tried and the result was 2V output offset and the amp going into protection.

C5 and C39 to me look like AC coupled feedback loop, 10n bypass same like on the input.

 

[darkhawk22]

Checking in to see if anyone is still using their M-25 power amp. I have an M-22 and am in the process of getting an M-25 for comparison.

 

[darkhawk22]

I've had my M-25 for a while now and i'm loving it. Lots of frequency range on this one for sure. Wondering if anyone has a complete list of Electrolytic caps as i'd like to one day change them out. The service manual has some listed but the format that I see online does not make sense.