More like trouble bleed. When you have a treble bleed circuit in your guitar, the fuzz face doesn’t clean up with the volume knob the way it’s supposed to. This isn’t just a fuzz face thing. A lot of vintage fuzz pedals interact with the volume knob and the trouble bleed will have an effect on the tone.
In this lesson I demonstrate the fuzz face with and without the treble bleed circuit. I like it a lot better without the treble bleed.