Sunflower / Sunface squealing at max gain

[nate433]

Apparently this isn't uncommon with fuzz face circuits. Anyway i love the transistors in it. The character of the pedal sounds great as is when i set the gain to 99%. So i was wondering if it was possible to swap the 1k fuzz pot to 500 ohm, then use a resistor in series so that to max resistance is 980 ohm or whatever is right before it squeals. Only issue now i guess is finding a 500 ohm pot. Tayda seems to be sold out and LMS doesn't carry them. If only they used a higher value.

Thanks!

 

[jwin615]

1 wouldn't change the pot
Make sure C2 isnt reversed
Move your Iap wiring around to see if it changes
If nothing, maybe try the 22-47p cap between C and B of Q2
Also. Maybe change C2

 

[Coda]

33p from c to b of q2 solves most Fuzz Face issues…

 

[nate433]

Hmm good to know. Is there a reason you don't see that included in PCBs? Does it affect the sound at all? Like it's better if you don't have to but it's nice to have the option?

 

[Coda]

Hmm good to know. Is there a reason you don't see that included in PCBs? Does it affect the sound at all? Like it's better if you don't have to but it's nice to have the option?

It acts as a filter; filtering out the unwanted frequencies (the squeals). It’s not in schematics because it’s not part of the circuit. Squeals, however, are. You could go through 10 Fuzz Faces, and maybe 3 would sound decent. Add that 33p cap, and all 10 would rock, most likely. The Fuzz Face circuit barely works as is. It is unstable by design. There are going to be unwanted audio artifacts. If more people back then knew about the 33p trick, no one would have switched to the Big Muff…

 

[hamerfan]

Hmm good to know. Is there a reason you don't see that included in PCBs? Does it affect the sound at all? Like it's better if you don't have to but it's nice to have the option?

There is a nice tutorial by Josh from JHS in youtube about explaining and modding the FF. That brought me into diy pedals.

 

[jwin615]

Hmm good to know. Is there a reason you don't see that included in PCBs? Does it affect the sound at all? Like it's better if you don't have to but it's nice to have the option?

It's just a path to ground for high frequencies. If you use a large enough cap, you can darken the pedal some IIRC. Just tack it on the solder side of the PCB.
Assuming you have some leads on Q2, put some clips on the and experiment with values. You might find that loading a little fizz is desirable.

 

[nate433]

33p from c to b of q2 solves most Fuzz Face issues…

Any thoughts if that didn't fix it. May even have made it a bit worse.

For what it's worth it's the BC108 version

 

[Guilherme Collateral]

Any thoughts if that didn't fix it. May even have made it a bit worse.

For what it's worth it's the BC108 version

Increase the cap value, I use 220pf, you can try a resistor at the input to reduce the input signal a bit. Solder a temporary pot wired as a variable resistor, turn it ‘till it sounds good, measure the resistance and solder a resistor with an aproximate value in place of the board input wire

 

[Guilherme Collateral]

Pictures of the board would be really helpfull, the wiring is very important