The Equinox Amp Overdrive project is a clone of the Marshall Guv’nor and Drivemaster. (The two pedals have different names, but they are identical circuits in every way except that the Guv’nor has an effects loop which has been excluded from this project).
First released in 1988, the Guv’nor was replaced in 1991 by the Drivemaster, the same time the Shredmaster and Bluesbreaker pedals were released. It was a very popular pedal at the time and remains well-regarded.
The Guv’nor was among the first overdrive pedals to use a 3-band tone control, allowing for more amp-like toneshaping via bass, midrange and treble knobs. Interestingly, while it looks like an amp tonestack on the surface, it’s actually a little closer to a Big Muff tone control in its technology. All three controls are much more interactive than you’d usually see on an amp.
The Equinox is faithful to the original, but with one added modification: a switch that lets you go between different clipping diodes. The original has a high clipping threshold using LEDs, but with the clipping switch you can also select two 1N914s in each direction, as in the Bluesbreaker, or one 1N914 in each direction, as in the Shredmaster.