switch-on transient in solid-state amp

[Confounder]

Hi. I have a solid-state bass amp that has suddenly developed a loud 'pop' when switching on. This happens even with the volume and gain turned all the way down (there is no standby facility). I feel sure, and would be extremely grateful if, some one could tell me where the likely problem is here (capacitor gone bad?).

Thanks.

[jrfrond]

In soild-state amps, the bipolar opamp and B+/- supply caps charge at different rates. First, they are not matched in value, second, one supply (usually the positive) is used to operate LED's etc., therefore those caps take longer to charge to capacity. This manifests itself as a DC "thump".

If your amp has a muting circuit, usually in the form of a speaker relay, the mute circuit might have become faulty, either a switching transistor or timing capacitor that might have opened up. If there is no mute circuit, or the mute circuit works properly, then it could be filter caps, but maybe not. My experience in chasing down DC thump problems in amps with no mute circuit is that you might never find the issue, even if you shotgun a ton of parts. Been there, done that.

[oc disorder]

Hmmm is it a pop or a thump ?
Just wondering if it maybe is just the power switch arcing ?
Especially if it is double pole ie switches both incoming mains wires
active and neutral.
Can you switch it on and off at the wall or an external plug board while
leaving the amp switch on ?
Although it's most probably what Jrfrond has said there is a possibility
the switch may be worn as it gets a lot of use.
Sometimes x suppression caps are fitted to quench the spark across the switch contacts.
Of course this is lethal territory so if looking take extreme care.

[Enzo]

And don;t assume that power on/off pops are a "problem" anyway. It is perfectly normal for many SS amps to pop.

A standby switch for a solid state amp? That would be like an effects loop on a bowl of spaghetti.

[jrfrond]

And don;t assume that power on/off pops are a "problem" anyway. It is perfectly normal for many SS amps to pop.

A standby switch for a solid state amp? That would be like an effects loop on a bowl of spaghetti.

HAAAAAA!!! Damn dude, you KILL me!!!

[Confounder]

Thanks for the replies, guys.

Fortunately, the transient appears to have been.......er, transient!

(And I take your point Enzo -- wasn't really thinking there, was I?!)