Fuzz Face Help

S

SurfaceDweller

New member
New builder here. I've put together 2 PNP germanium fuzz faces, battery power only. They both work great, but one of them has a "quirk".

When the guitar's volume pot is at or near 0 (off), it's like some kind of noise generator turns on. It sounds like oscillating frequencies, so I'm guessing it's some kind of radio interference. I think changing the length of cable after the pedal changes the frequency of the noise. This only happens when the pedal is engaged.

My other fuzz face does not do this. Could this be an issue with the way the circuit is grounded? To be honest I was a bit confused about where all the ground leads go...

Thanks!
 
SurfaceDweller said:
New builder here. I've put together 2 PNP germanium fuzz faces, battery power only. They both work great, but one of them has a "quirk".

When the guitar's volume pot is at or near 0 (off), it's like some kind of noise generator turns on. It sounds like oscillating frequencies, so I'm guessing it's some kind of radio interference. I think changing the length of cable after the pedal changes the frequency of the noise. This only happens when the pedal is engaged.

My other fuzz face does not do this. Could this be an issue with the way the circuit is grounded? To be honest I was a bit confused about where all the ground leads go...

Thanks!
Click to expand...
You should post pictures. Otherwise we don’t have any way of helping you.
 
I would ground everything to the jack, with no two ground points connected (star-grounding). Secondly, Fuzz Face circuits, mainly Si ones, can squeal/oscillate due to RI. Your Gi’s might have been a bit higher gain, perhaps. The issue is about as classic as the FF enclosure. The solution is a 33p/47p cap between the base and collector of Q2…
 
Coda said:
I would ground everything to the jack, with no two ground points connected (star-grounding). Secondly, Fuzz Face circuits, mainly Si ones, can squeal/oscillate due to RI. Your Gi’s might have been a bit higher gain, perhaps. The issue is about as classic as the FF enclosure. The solution is a 33p/47p cap between the base and collector of Q2…
Click to expand...
I see, thank you for the advice! I may give that capacitor trick a try.

I have noticed that the issue is most apparent when running my pedalboard after the fuzz. I've read that FF's can interact badly with other pedals, and this seems to be the case.
 
SurfaceDweller said:
I see, thank you for the advice! I may give that capacitor trick a try.

I have noticed that the issue is most apparent when running my pedalboard after the fuzz. I've read that FF's can interact badly with other pedals, and this seems to be the case.
Click to expand...
That's more so an issue with pedals before it due to impedance mismatch.
Never had much issues running pedals after fuzzes aside from input levels.
 
I put a 30p cap between the base and collector, but I accidentally wired it to Q1. At any rate it has greatly reduced noise from the pedal, so, mission success!
 
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