geekmacdaddy
Well-known member
Built for a friend. Sounds like the youTube vid of the real thing, but oscillates 'round 9, and 10....
Grover Drive
- Thread starter geekmacdaddy
- Start date
Anotherpedalbuild
New member
Mine too. I tried a few things, swapping chips/transistors. No luck. Cured the problem by removing the input wire and replacing it with a 115k resistor. Found that using a pot between the fxin and the switch dialled out the oscillation. This pedal has way too much gain, but I couldn't be engaged enough with the tone to debug it properly.
TeleCrunch
New member
My solution was to remove C2, the 100n cap directly connected to input in the schematic. It looks like may have been an error in the original tracing? I think it would be more likely that the cap end that connects directly to the input would be better going to ground at that spot, if it’s actually in the circuit, making it follow the input resistor and smoothing the high end even more going into the op amp. I preferred just removing the cap than directing to ground.
Flashheart
Member
Thanks man!!! Removing C2 totally worked.
Chuck D. Bones
Circuit Wizard
C10 is definitely a likely suspect. Note that the Silicon Fuzz Master has 10K (R5) is series with both input capacitors (C2 & C4). The Dover Drive has no resistor in series with C10.
Removing C10 knocks the gain way down and flattens the freq response. If you're looking for a freq response similar to the original, but with less gain, try this:
Remove C10
Change C1 to 15nF
Change R2 to 10K
Tweak R2 to adjust the maximum gain (more resistance = less gain)
Tweak C1 to adjust bass the cutoff (more capacitance = more bass)
C1 & R2 interact, so if you change one, you may need to adjust the other. "Engineering is an iterative process."
NB: like most Fuzz Faces, this pedal circuit is sensitive to whatever is driving it. It will behave completely differently if it's driven by a guitar compared to driven with a buffered bypass pedal. Removing C10 significantly reduces this sensitivity.
Removing C10 knocks the gain way down and flattens the freq response. If you're looking for a freq response similar to the original, but with less gain, try this:
Remove C10
Change C1 to 15nF
Change R2 to 10K
Tweak R2 to adjust the maximum gain (more resistance = less gain)
Tweak C1 to adjust bass the cutoff (more capacitance = more bass)
C1 & R2 interact, so if you change one, you may need to adjust the other. "Engineering is an iterative process."
NB: like most Fuzz Faces, this pedal circuit is sensitive to whatever is driving it. It will behave completely differently if it's driven by a guitar compared to driven with a buffered bypass pedal. Removing C10 significantly reduces this sensitivity.
Last edited:
