Soundstream Ref.405 railvoltage at sub-ch.

[gisewhcs]

As I'm planning to spend some new caps to my girlfriends amp I'm wondering what's the railvoltage for the subchannel?

The schematic just says "Sub-Rail", great!
The other channels run off +/-26,5V as the schematic tells me, so 35V rated caps would be ok.

It's still in the car and I don't want to/have time to remove it for measuring.
As I have the schematic and some hi-res pics of the board it wouldn't be a problem to order the parts.

Because I want to spend some extra capacitance to the secondary and you don't have much hight in the sink for bigger caps,
I need to know the railvoltage of the subchannel.
I don't believe it needs the 50V rated ones, so I can maybe look out for flat ones with higher capacitance that will fit in there.

[Perry Babin]

The 405s appears to have approximately 45v on the high-power setting.

There's probably no point in replacing the capacitors unless they're defective.

[gisewhcs]

I just saw the transformer ratio in the schematic, 3/10 in the high power setting and 3/8 in high current.
So you are right with something around 45V.

I wanted to change them because the amp has a little turn-off pop in the subchannel, and I hope replacing the caps and resoldering the whole thing will solve this.
It's definitive not caused by a bad chassis ground or the radio, double checked that already.
As the amp already had bad solderjoints on one of the normal channels' FEB, I believe this is a good piont to start with.
And I don't know who used or abused this amp before, and the caps are from somewhat around 1995 or so...

I nearly always put new caps in such old amps, preferring Panasonic's FC Series.

[Perry Babin]

If I'm not mistaken, this (turn on/off noise) was a common problem and not easily solved. Maybe someone has dealt with this before and can provide a bit more information. I think there was a similar problem in a thread for a 705.

[gisewhcs]

I just read through nearly all Soundstream threats and found something about a pop issue in an threat about an MC245.
I believe that design is a bit too different from mine to be comparable, right?

In that threat an, I believe ex Soundstream engineer, mentioned some kind of relay board being added to that amps to get the problem solved.

I think, I will give resoldering and recaping (correct english?!) a try first.