Q2 collector voltage on fuzz changes when played

[rousejeremy]

I never knew this before.

[R.G.]

There are many ways this can happen, especially in circuits which clip. No biggie. Bias point shift is common in such circuits.

This is one reason that all voltages are taken with zero signal, unless specifically mentioned otherwise.

[rousejeremy]

Thanks R.G

[LucifersTrip]

yep, and be careful...even if you don't play a note, feedback can also change the voltage...best to take readings when the volume is not real high.

[PRR]

> collector voltage on fuzz changes when played 

This means your fuzz is distorting.

Specifically it suggests 2nd-harmonic distortion.

I fool with tube amps, often clean. Often on bench with dummy-load, not listening. Monitoring the grid voltage is a convenient way to know that the signal level has gone high enough to shift from clean to distorted.

Here's an analogy. You are on a pogo-stick, bouncing from ground to 10 feet up, average 5 foot. Now bounce into an 8 foot garage. Since you can't go higher than 8 feet, your average height shifts from 5 feet to 4 feet.

[kurtlives]

Current is flowing!