drive/boost into Tonebender Mk2

[m7b52000]

I have just built a Mk2 TB on tagboard as an experiment. After much dicking about with many transistors and bias settings it sounds OK but a bit splatty with single coils and gates a bit too much as the guitar signal fades. As an experiment I tried a drive pedal in front with it's level pretty high. The combo sounds majestic with masses of sustain and no gating. Is this typical Mk2 behaviour?

[kaycee]

Something is off with your build, I'd suspect. The mk2 is pretty aggressive and smooth, and will get more so if driven with a boost or compressor.

[Rob Strand]

The combo sounds mI have just built a Mk2 TB on tagboard as an experiment. After much dicking about with many transistors and bias settings it sounds OK but a bit splatty with single coils and gates a bit too much as the guitar signal fades. As an experiment I tried a drive pedal in front with it's level pretty high. The combo sounds majestic with masses of sustain and no gating. Is this typical Mk2 behaviour?ajestic with masses of sustain and no gating. Is this typical Mk2 behaviour?

You can get a spatty sound if the collector voltages are biased to low.   For the TB2 it's likely to be the first or third transistor.    If you measured the collector voltages of Q1 and Q3 they should sit around 8V from "ground" ("ground" being the emitter point of Q2).  You might be able to find some voltages posted on the forum.

Speaking generally,  the splatty sound comes from the signal riding around the bias point.     Usually the cause is one particular stage.    When you jam a strong signal into such a stage the transistor(s) will go largely the between off an on states and spend less time riding around the splatty misbiased point.  So that's why the splatty sound disappears.  It's hiding the problem rather than fixing it.     When you have coupling caps between stages that can do some weird stuff as well.

[Steben]

Bias points are exactly what some "bias" or other character control pots are about on some circuits. With them you can misbias if wanted when you need splat or gated. Ild start with trimpots at the collectors.