The Corona Overdrive project is a clone of the BOSS OD-1 OverDrive, originally released in 1977, which is known for being the first overdrive effect to utilize diodes in a negative-feedback arrangement for clipping purposes. Like the Distortion+, it lacks a tone control, but most who play through it say it doesn’t need one.
There have been a couple of different versions of the OD-1, with a major circuit revision in 1981 that dropped the quad op-amp for cost-savings reasons, but most players who have A/B’d the versions say the original is better. This project is for the original quad op-amp circuit.
There are two switches available: one for clipping diodes (with enough pads available for any diode combination you can dream of, as well as “comp cut” or diode lift in the middle), and a second one that changes the EQ of the circuit to have more low-end and fullness.