ZVEX EFFECTS Tremolo ProbeThe Tremolo Probe is a kind of cross between a theremin volume control and a Super Hard On. There is a 3 5 8" square copper plate mounted on a chunk of 3 8" clear acrylic that passes over the top of the pedal housing, angles down to sharp turn, and goes back to the pedal. Under the whole mess is a 3 5 8" by 7" sheet of aluminum that provides shielding from annoying ground effects and wires under the stage. It also serves to protect the knob from being