Snap or pop followed by momentary loss of volume

[buildAndPlay]

I've got an old Eden 210 combo. It's a 200 watt solid state bass amp for those unfamiliar. Anyway, it has developed a problem where you'll be playing and all of a sudden it will make what I'll call a loud electrical snap or pop sound, followed by a momentary loss of volume. This is something that has happened on stage at a few different venues, but I have been unable to duplicate the problem at home.

My guess is that maybe it's happening in situations where the voltage is lower than at my house. I'm considering changing out the two large power supply capacitors, but wanted to know if anyone thinks those could cause the symptoms I'm experiencing first.

Thanks,

Jim

[Jazz P Bass]

There are a whole pile of parts in that amp.

If you want to guess that it's the power supply capacitors, have at it.
At least measure the Vac ripple that is on them.
That may provide a clue.

If you cannot duplicate the problem on the bench, that makes it even more difficult to resolve the issue.

After taking a few basic voltage measurements, I would flip the board over & inspect the solder job that the factory did.

[MarkusBass]

My guess is that maybe it's happening in situations where the voltage is lower than at my house.

This is the last thing I would think of. Why you think so? Do you have a chance to measure the voltage in any of the venues?

I'm considering changing out the two large power supply capacitors, but wanted to know if anyone thinks those could cause the symptoms I'm experiencing first.

The problem looks rather like cold solder joint. Something like on this photo:
http://upload.wikimedia.org/wikipedi...der_joint2.jpg
I would look carefully at the printed board. You may also try to reproduce the problem by tapping components with a wooden stick.
I wouldn't change the capacitors without further tests.

Mark

[Justin Thomas]

Another vote for "bad connection somewhere." Since you can't dulicate it on the bench, I'd have someone whack (the Enzo Whack) it real hard while you play it first, before you get it all apart. Then chopstick it. Bet you'll find the aforementioned cold solder joint. Let the amp warm up first; could be brought on by expansion as parts heat up.

Shotgunning = bad.

Justin

[buildAndPlay]

This is the last thing I would think of. Why you think so? Do you have a chance to measure the voltage in any of the venues?

Well, it's the only thing I could think of that might be different between the venues and my home. I've played it loud and hard at my house trying to get it to do it. I wasn't playing it that loud at the last gig where it acted up on me, which was an old theater.

The reason I suspected the caps was because of the way it would cut out and then the volume would come back up. Almost like the caps had been drained and had to recharge. But I have no idea if that's a thing or not, which is why I posted the question.

Anyway, I'll check the solder joints and try tapping on things and post my results here.


Jim

[J M Fahey]

That amp has a compressor/limiter.

Any loud pop can trigger it and mute volume, which then comes back to normal after 1 or 2 seconds.

Yes, there is a capacitor involved, but not a supply one.

[buildAndPlay]

That amp has a compressor/limiter.

Any loud pop can trigger it and mute volume, which then comes back to normal after 1 or 2 seconds.

Indeed it does, and I play with the compressor on too, so maybe something early on in the signal path then.