Author Topic: Fuzz Face Fuzz Pot  (Read 904 times)

skypn

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Fuzz Face Fuzz Pot
« on: March 25, 2020, 07:56:15 AM »
Yet another question:
Seeing I'm stuck in the house for 2 weeks, I'd thought I would try and finish up some boxes. I've breadboarded a classic Fuzz Face using silicon NPN trannys. The schematic calls for a 1KB pot for the fuzz. I have used both a 1KA, and a 1KC, because that is what I have on hand. I don't get fuzz with either one until the knob is around half way up. Although the reverse audio pot is a tad better, it is solder lug, not PCB mount, as I have my PCB designed, but no bigger there. Before I order pots, and have to wait on shipping to finish, will the 1KB have a better response, or should I buy smaller pots, like 500ohm? I still will have to wait, but I already have a truck load of pots that never seem to be what I need. I've tried bigger pots, to no avail, so I guess I understand how they work...all the way off is the highest resistance, decreasing as you turn it up (am I right?).
TIA
BTW, it sounds great! I would just like to spread out the level of fuzz a little
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mjg

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Re: Fuzz Face Fuzz Pot
« Reply #1 on: March 25, 2020, 03:00:29 PM »
If you can, why not find the place on the pot where you think it starts to sound good, then measure the resistance at that point.  That might give an idea what sort of values sound good to you, and that should help you decide whether a smaller or larger pot will be what you need. 

Personally I prefer a C pot for fuzzes.

skypn

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Re: Fuzz Face Fuzz Pot
« Reply #2 on: March 26, 2020, 04:55:51 AM »
Thank You, great idea. I'll give that a try.
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FuzzMonkey

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Re: Fuzz Face Fuzz Pot
« Reply #3 on: April 23, 2020, 10:52:09 PM »
Personally I prefer a C pot for fuzzes.

+1.

WormBoy

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Re: Fuzz Face Fuzz Pot
« Reply #4 on: April 24, 2020, 12:19:07 AM »
Note that, in the classic Fuzz Face circuit, the fuzz pot is wired as a voltage divider, not as a variable resistor. In this circuit the pot offers a constant resistance to ground for the transistor, plus a variable boost from the bypass cap on the wiper. Changing the value of the pot will change the resistance to ground and thereby more than just the 'spread of fuzz on the pot'. This is DIY, so do whatever sounds good to you, but if you like the sound with 1k to ground there, you should look at the taper of the pot and not its value. For the Fuzz Face, 1kC works best but you'll still have all the 'good sounds' at the last part of the sweep.

Of course, if you want to get fancy, you could put a 500R resistor in series with a 500R pot (connect fixed resistor to ground). That leaves a constant 1k to ground, but the pot will cover the interesting part. Or just forget about the fuzz pot and wire a fixed resistor with the cap there, and use the volume knob on your guitar  ;).