 It has been cloned many times, most famously by the DOD 250 Overdrive (a distortion).The pedal uses a single op-amp and a pair of germanium diodes to ground (parallel-push) for clipping in a very simple configuration with only Output and Distortion controls, no tone control; the pedal uses no discrete transistors.Turning up the Distortion control increases the amount of distortion and at the same time boosts the treble in the signal.