Boss OD-1 Overdrive

Schematic from the OD-1 service manual dated Dec 26, 1980

Released November 1977 (according to BossArea.com)

Series feedback clipping diodes, asymmetrical.

Output is inverted with respect to the input.

No tone controls. Second op amp stage simply a unity gain inverter (why??)

Often compared to the Boss SD-1 Super Overdrive due to the shared drive stage, but very different following stage. Note that the OD-1 is phase inverting, while the SD-1 is phase coherent.