Here’s an older design from Catalinbread, but an interesting design as usual. It’s a preamp/boost with a wide range of tone shaping capabilities. Schematic can be found here.
Catalinbread VariOboost
Tools, Tones and Toys for Guitarists
Here’s an older design from Catalinbread, but an interesting design as usual. It’s a preamp/boost with a wide range of tone shaping capabilities. Schematic can be found here.