MU Distortion Pedal
The Mu is a combination of a couple classic circuits with some modifications.
The “Gain” control is the volume for the boost side. The Boost is first in the “signal chain”.
The second half is a hard clipping distortion/pre-amp that can go from a near clean boost to a saucy crunch distortion tone. The clip switch allows for the changing of the clipping components. The Distortion is controlled by the "Volume" and "Drive" knobs.
For the adventurous dimming all controls will even start to get you into fuzz territory.