The speaker moves air inside the pedal and the microphone picks that sound up again, so the signal feeds back on itself. The result ranges from touch-sensitive overdrive to heavy fuzz, harmonic feedback and wild oscillation.

DI Out and Mic Out set the balance between the direct amplifier signal and the microphone signal. Gain includes an overload range, Tone shapes the amplifier EQ, and a switchable noise gate keeps the microphone under control.

A selector adds digital reverb, tape-style echo or chorus, with Depth and Time controls for each. An external speaker output mutes the internal speaker, so the pedal can drive a cabinet instead.