Fuzz amount pot

[doctortropico]

Hey all,

Experimenting with a fuzz for bass.
I  use a 50K pot right after the signal in to reduce the input level, and thus have some control over the amount of fuzz.
It works, but it doesn't feel like a real amount control.

Looking at other fuzzes, i see a lot of connecting the base of Q1 via a resistor to the emitter of Q2 and routing that to the ground via a cap and a pot. (like I found here, I hope you don't mind that I use your .gif, Beavis)
I tried it, but since I had no idea of what the values should be for my setup, it didn't gave me a good result.

How would I have to calculate the proper values, or how would I be able to build in a nice "fuzz amount"?

Many thanks.

[nocentelli]

The "pot with a Q2 emitter resistor bypass cap" is the standard fuzzface fuzz or gain control. The input series pot you have tried is often called the "smooth/pre-gain" control when used as a mod to the fuzzface. Your circuit appears to be two bazz fuss circuits in series: the standard gain control mod for the bazz tends to be a 1k pot as variable resistor to ground off the emitter. I actually built a circuit almost identical to the one you've posted a while ago, but I used a dual ganged 1k pot as a gain control on both transistors simultaneously. It didn't sound so good. The bazz fuss is really only good for running at maximum gain (which you have already with the grounded emitters) and doesn't sound so good when you lower the gain via emitter resistor (like I tried) or by reducing the input signal. You could try a pot (or two, or dualgang) in place of the collector resistor(s) perhaps, but I'd advise trying another circuit if you want decent lower gain sounds.

[doctortropico]

Indeed, I started out with the Buzz Box, which is two Bazz Fuzz circuits in one.

Thanks for explaining the two types of control a bit.

Any tips on a bass fuzz that gets really dirty at max gain, but also has a bit more control?

[nocentelli]

Any tips on a bass fuzz that gets really dirty at max gain, but also has a bit more control?

The stock, single bazz fuss is a great starter project, and sounds pretty cool for a circuit with only five components, but I haven't come across many mods that improve it that much. Running two in series gives a bit more filth, but not as much as you would expect. Extra tone and gain controls seems to take away from the sound rather than add to it. It really doesn't sound much good at lower gain levels, but if you want a lot more dirt, adding another diode with reverse orientation to the original one (a bit like a big muff but without the DC-blocking cap) gives more dirt (although it can become a bit gated): Using an anti-parallel pair of LEDs instead of diodes gives even more dirt, and a significant volume boost as well.

The zvex woolly mammoth is supposed to sound pretty good for bass, it's basically a fuzzface with a few extra controls and a big muff style tonestack. I'd suggest maybe just trying a silicon fuzzface, but with an "input cap blend" (google it) on the input.

[doctortropico]

cheers!