squelch unit?

[joel]

I would like to make sort of an effect unit (stompbox-like with knobs)
with what i can add more "squelch" to a sound, and a knob for
the amount of squelch i would like to have, how could i do this
and what do i need? (i don't know too much about transistors & things..)
Or is this all making no sense? i mean i have this
idea, but i don't know if it is at all possible.

Any help is appreciated.