Debug - Stomping stompbox

[matan]

so i m trying to make a stomp box box, or foot drum using piezo.
BUT - i want an input for a guitar, so i can use my 1 input amp.
so i made it very simple:

piezo --> 500k pot --> output  <-- input

actually the input\output can be switched.

for some reason the circuit is "dead". i plug it in and get nothing but silence, no matter if\what i plug in the other end.
cheked continuity, cheked the piezo. cheked the pot.

What basic am i missing?

[duck_arse]

show us a circuit diagram, and photos of what you have actually built. then we might see something.