How does Fuzz Factory Gate Work?

[One-Eyed Shaman]

Could someone please explain to me how the gate function of the Fuzz Factory works? I've searched for simple ways to make a gate and have only found schematics for entire noise gate pedals. But it would seem like the Fuzz Factory has a very small, simple method of adding a gate to a fuzz. Could someone explain how that works? Like if I wanted to apply the gate of a Fuzz Factory (with the threshold/sensitivity controlled with a pot) to another fuzz design, would that be possible?

[cloudscapes]

It doesn't work like a noise gate, so it can't really be comparable with noise gate effects. I'm not a transistor guy, but I think gate just varies the bias voltage on a pnp's collector to make it choke if the sound is too low. Something like that. Good for a fuzz pedal, because it's noisy and glitchy, but not really that good if you're just trying to make a classic noise gate.

A classic noise gate will require more complexity because there needs to be a "fade out" time, and it has to be smooth sounding, not crackly or glitchy (which are benefits for the ff).

[One-Eyed Shaman]

So am I correct in understanding that the gate control on a Fuzz Factory is essentially a Bias control?

So would a bias trimmer on a silicon Fuzz Face work or sound similarly?

[antonis]

Strictly speaking, it isn't a bias control - but it depends on what side you face it..

It sets the Gain level on the Collector of the 2nd transistor (which in turn is in cascode to bias the base of 3rd one..)

[Snufkinoob]

So am I correct in understanding that the gate control on a Fuzz Factory is essentially a Bias control?

So would a bias trimmer on a silicon Fuzz Face work or sound similarly?

If you replace the 8k2 on a fuzz face with a 10k pot, you can get gated/glitchy tones. Not sure if it will sound/behave exactly like the fuzz factory gate control, but it should do the trick.

[kaycee]

It doesn't really do the same thing, although with a larger pot, say 20k and some series resistance you can get some Factory type sounds. On the Factory, the gates main function is to stop the thing screeching its own head off. You adjust the other controls and then use the gate to shut it up, if you want to that is of course , then you might be left with something usable, or though usually not I have to say...

[One-Eyed Shaman]

I'm running a booster before the Fuzz Face circuit for increased gain/sustain, so I'm trying to gate the higher noise floor that occurs because of that compressed dynamic range. I just need it to cut out the rise in noise when notes aren't being played. (But if the bias control can alter the character of the fuzz as well that's cool too)

Do you think replacing the 8k2 with a 10k or 20k pot with series resistance (and how much would you say?) could achieve this?

[kaycee]

A raised noise floor is to be expected when stacking gain circuits. If your Fuzz Face is a germanium one then you'll get that hiss amplified, a silicon one will be quieter. You could try running the booster after, or try a compressor instead, before or after as well.

[kaycee]

I forgot to spill the beans on the bias adjustment.

The original resistor is 8k2, so if you replace that with a 10k pot then you get an extra 1k8 resistance to add, and of course the full range down to zero.

In some instances, allowing the full current through could damage the circuit (in the case of the Fuzz Face it doesn't  but so) so it's good practice to add some series resistance to prevent the line going open. In this instance something like 4k7 or 3k3 would do, then you never get less than that set value, and you get greater maximum resistance too.

Not all of the sweep will be useful of course, some transistors will give better range than others.

[LightSoundGeometry]

I usually get these type of sounds, noises and tones similar to pvrex and levi never, when I use bad transistors or junk transistors ..mismatched pairs, unbiased as if a blind man put it together

just saying