Eliminating Power Switch Pop?

[bkanber]

Hey all,
This seems like a standard question, but I haven't been able to find the answer on the boards here yet. I have a new build that uses a 3PDT stomp switch for true bypass.. because the switch controls power, every time the pedal is turned on it makes a loud pop. I was wondering if there's any way to filter that turning-on-popping-noise out. A friend mentioned that a cap should do the trick, but what size, and connected to what?

Any suggestions?

Thanks,

  Burak

[R.G.]

It may not be possible to eliminate popping from that setup, because it's not your switch that is popping. It's the circuit itself.

Think about it - when the circuit is suddenly turned on, it has to establish all of its internal conditions, including the internal voltage point on the output capacitor. That makes for a huge pop, probably about half the power supply. Filter it and slow it down and you get - that's right, a huge thump. All you've done is remove the high frequency edge from the pop.

The non-popping answer is - don't do that. Set your circuit up so the power is not toggled by the bypass switch, only the indicator LED, if you have one. That way the circuit is already at the proper voltage and does not produce the pop if everything else is correct. That's why almost all effects put the power "switch" into either the input or output jack by using a stereo jack on a mono circuit. It's all in the FAQs.

[bkanber]

Gotcha. I found that the circuit doesn't pop now that ground is attached to the metal enclosure. But that's something I'll keep in mind for future projects... thanks a lot!