This project is based on the Marshall The Guv’nor and also the Danelectro Daddy-o, which is basically the same circuit as The Guv’nor with input and output buffers added. This is the circuit for the original black unit from the 1980’s, not any of the later, inferior versions. This is a very versatile distortion effect, one of the best ever made in our opinion. With the tone controls, it is possible to get a nice variety of sounds.

Description from General Guitar Gadgets.