Zvex Tremelo Probe Pedal
What does this pedal do?
The 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 knocked off if you drop it on that end... and it makes a nice toe chopper if you are barefoot, so (legal disclaimer:) DO NOT DROP THIS PEDAL ON YOUR FOOT! IT IS HEAVY AND HAS VERY POINTY CORNERS THAT COULD DAMAGE LIVING CREATURES AND FINE HARDWOOD FLOORING. ALSO, YOU COULD BREAK SOMETHING. Like your dog.
How does it work?
The copper antenna projects a field of RF energy that is affected by your foot (or other appendage), altering the circuit that generates it, an in so doing, increasing the brightness of that LED on the top of the pedal and also controlling the master volume of the output. You can set the drive of the pedal with the knob on the back... it gets pretty darn loud, so watch out. It will distort in an interesting way when it is cranked. Basically, the reason it is called the tremolo probe is that you can tap on the antenna at any speed and your sound will be a nice tremolo in time with the band. It is possible to set the volume to be up slightly when your foot is off the antenna and come up louder as your foot approaches the antenna.