Maxon OD820 hiss

[J M Fahey]

Good work.
Besides, now we *know* noise does not come from HF switching.
Before, we could only guess.
Tha final word lies in the actual experiment.

[Steve Conner]

I've also noticed microphonic noises from pedals ahead of a high-gain overdrive. Any two conductors with a DC potential between them can act like a condenser mic. If one of the conductors moves, the redistribution of charge makes a tiny signal. If the circuit has enough gain and high enough impedance, you'll hear it.

The most effective cure is to use less gain. But you might also like to try tapping any ceramic disc capacitors in your circuit to see if they're microphonic.

[ninjadave7]

Good call, I'll try tapping around and see what I find.