The Valve Caster 2.0: Tube Boost and Overdrive: 7 Steps This boosts your signal really well. I had my amp on 1 and the Volume control on the pedal about 1 or 2 and boy was it loud! I used a 500k pot plus a 470k resistor in series at the first plate of the second tube as a Distortion control. however it doesn't seem to affect it much. Is This The Best Tube Based Boost/Overdrive Schematic To wwwi››The DIY Channel›Burnt Fingers DIY EffectsDec 19, 2013Is This The Best Tube Based Boost/Overdrive Schematic To Use? Discussion in 'Burnt Fingers DIY Effects' started by The first question is which kind of tube distortion will you prefer? Since the only part that draw any current to speak of whatever tube pedal you build is the tubes heater which draw 150mA at 12 volt and 300 mA at 6 volt