This is my version of the Matsumin Valvecaster overdrive pedal. It uses a 12AU7 dual-triode vacuum tube, with the filament heaters wired in series at 12v pulling 150mA. (I built this pedal back in 2011, and looking back now the internal wiring makes me cringe.. my apologies!) :)
Schematic:
http://www.matsumin.net/diy/jisaku2/Valve_Caster/Valve_Caster_10.BMP
Photos and Parts List:
https://www.flickr.com/photos/timpatterson/5518410553/
I think it sounds good, and I probably should have put on some new strings before the demo. Also, please forgive the mediocre playing, I'm a bass player who just dabbles in guitar and electronics. :)
▶️ DTube
▶️ IPFS