Sola MKIII and guitar's volume knob

[angelodp1]

I know this is an old thread... for the 3 knob Tonebender, would trimmers for bias be in order on all three collectors? I have a build I like and want to finesse the bias. Would 10k trimmers at the collectors do the trick.

[Harry Muff]

None of those transistors are biased - going by the base-emitter voltage difference. PNP, the emitter should be more positive than the base by around 0.2V?

Do you have the power supply polarity right? This is positive ground. Easy & frequent mistake - rookie or not.

Or maybe that 220k bias resistor is too high value or missing - or the 47k bias is really 4.7k (might explain the darkness). Anyway, look thereabouts.

they should just redraw these layuts with trimpots !! im not that talented or I would alter the drawing for variable resistors

[Harry Muff]

I know this is an old thread... for the 3 knob Tonebender, would trimmers for bias be in order on all three collectors? I have a build I like and want to finesse the bias. Would 10k trimmers at the collectors do the trick.

didnt see this but that is what I suggested .. all the drawings should be redone for variable pots

[mdcmdcmdc]

I haven't found TB MKIIIs to be particularly fussy when it comes to bias or voltages. It's a great sounding circuit that's very forgiving.