A precursor to the legendary Tubescreamer, this early green Ibanez overdrive from 1977 has a sound all its own. With its diodes-to-ground clipping setup, the OD-855 Overdrive II actually has a little more in common with an MXR Distortion+ or DOD 250 than with a Tubescreamer. Like other Ibanez pedals, this one was designed by Maxon, whose name is on the original PCB and inside the enclosure, but this one was exclusively released under the Ibanez name.
This project is an exact copy of the original, but allows for an optional diode switch mod. While the original uses germanium clipping diodes, this board includes space for a switch and second set of clipping diodes if you’d like to experiment. There’s also an optional “Softness” trimmer to adjust the clipping threshold of the mod side of the switch, and if you use a center-off toggle switch you can get a third “diode lift” or “comp-cut” mode.