Working on a new circuit at this moment, it’s inspired by some existing guitar overdrive pedals.
The main gain and overdrive stage is basically one slightly enhanced Proco RAT gain stage but with more potential gain and volume (instead of the RAT’s multiple lower gain stages) . The clipping type is what’s called the “soft clipping”, with LEDs in the negative feedback chain. The LEDs in theory would allow for good enough output volume thus eliminating the need for an additional gain recovery stage after the overdrive stage. That’s in theory of course 🙂
Will be prototyping this on a board soon hopefully. Will still need to tweak its frequency behavior, and set up its minimum and maximum gain and volume. Might also add a tone control later – certainly not the one used in the original RAT, don’t want it to be scooped like that one. Will probably go towards some mid boost à la Tube Screamer instead. Sort of tempted by having a tone switch with two preset tones instead of a continuous potentiometer.
It has a buffer at the input. I’ll also test it without the buffer to see how this one-transistor thing behaves. The input impedance will be significantly lower without the buffer, it may bring some interesting results like easy cleanup using guitar’s volume. Don’t know if I need it, worth testing anyway.
The simulation is showing it’s doing something already 🙂