Pioneer A400 Popping on Power Off

[mhk1058]

Just replaced my Pioneer A400 psu smoothing caps with 10000uF 63V Mundorf MLytic capacitors and also changed the caps at C201/C202 (coupling caps?) as well as the one at C306 next to the PSU smoothing caps.

The amp works fine apart from the fact I now get a pop from the speakers when I switch the amp off. Happens with volume turned right down and all peripherals turned off.

It's not very loud but it's enough to move the speaker cones a fair bit.

Is this something to worry about, just a product of different caps or have a done something I shouldn't?

 

[TrevC]

If it works well otherwise I wouldn't worry about it. I have an old Armstrong amp that does something similar.

 

[mhk1058]

If it works well otherwise I wouldn't worry about it. I have an old Armstrong amp that does something similar.

Thanks, yes I'm sure I've heard other amps do it but just a little concerned that this one didn't do it before the change of components. The original smoothing caps were 10,000uf and 50v, others like for like. Don't know enough to understand if that is the cause.

 

[Vladimir]

Can you hear the relay click when turning the amp on and off?

 

[eggontoast]

What value cap did you put in C306 ?

 

[mhk1058]

Can you hear the relay click when turning the amp on and off?

I can hear the relay when switching on, can't hear anything over the speaker pop when switching off.

 

[mhk1058]

Just the same as came out, 0.47uf 50v. However, I was wondering if that was the culprit. No idea what it does but based on the facts that if there was something wrong with the smoothing caps I'd be in trouble, the caps at C201/C202 are channel specific and this is both channels, so it has to be due to something C306 is doing - or not doing.