The way fuzz knob on a Fuzz Face works

[iamjackslackof]

Hi all,

Couple quick questions on the operation of the Fuzz Face. I have several FF clones and variants, and on most, if not all, of them, the fuzz knob's very last 1/8th of a turn or so really kicks in the gain and fuzziness. My Chase Tone Fuzz Fella and my PPCB Twin Face both do it, off the top of my head. Been a while since I tested my Analogman PPCB clones.

I like to use FFs at slightly less than full gain, either with the knob or my guitar volume, and ideally I'd knock the fuzz knob back just a hair from max, but because of the way that last little bit adds so much more gain, it almost seems to function closer to an on/off knob, rather than a smooth linear increase.

Question 1 is, what causes this, electrically?

Question 2 is, are there any mods or FF variants that don't have this behavior, and if so, how are they achieving it?

 

[Harry Klippton]

It's really common to use a C taper pot instead of a B for this reason

 

[iamjackslackof]

Ah of course! So it is a taper thing then. I may have to swap out the fuzz pot on my Twin Face then, and see how it changes things.

 

[Harry Klippton]

As for how it works, I can't say. Someone more knowledgeable can explain that. What it looks like to my uninformed perspective is similar to cathode bypass caps and resistors in a cathode biased tube stage since the fuzz pot is between the emitter and ground