Hey guys my rhythm guitarist and I plan to make Big Muff replica's from the PCB's sold on generalguitargadgets.com. I plan to make a triangle knob version of the muff. What I want to do in addition to the replica is add a top boost circuit with a knob to regulate the amount of top boost and add a separate switch to turn the top boost on and off.

Basically I want to build a pedal similar to the metal muff but instead its a Big Muff with a top boost.

Does anyone know where I can find the schematic for a top boost circuit that fits my specifications.