Your Source for DIY Pedal PCBs and NostalgiTone! › GuitarPCB Forum › General DIY Pedal Discussion › Many-knob Fuzz
- This topic has 5 replies, 2 voices, and was last updated 2 years ago by
peeeeeeej.
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April 1, 2024 at 8:48 pm #31756
peeeeeeej
ParticipantSo I got weird with a One Knob Fuzz board:
- 3PDTs for toggling Q1 (BC109/2N4401) and Q2 (BC108/2N3906)
- DPDT on/on for toggling C1 (100n/1u) and C3 (220n/22n)
- Sag circuit a’la the test kit schematic (9v > 2k resistor > B10k pot) between a 9V pad on a 3PDT board and the main board
- R5 is a 2k potentiometer
learnings:
- R5 does not control gain lmao, I think it regulates power maybe? It seems to do a better job of sagging the circuit than my sag circuit
- sag works fine if the R5 potentiometer is set to half or lower, but barely affects the circuit otherwise
- toggling the cap at C1 is an idea I stole from a fuzz face DIY mod suggestion, and figured it might work since the OKF topology seems very similar, it doesn’t seem to do much.
- same with the tight switch at C3 no significant difference
otherwise this thing was cool and it was a fun experiment! Excited to rework this and make it do more of the things that I’d like!
April 1, 2024 at 8:55 pm #31757peeeeeeej
ParticipantOh yeah, pics (forgive the bending of the socketed caps, it’s busy in there):



April 1, 2024 at 9:52 pm #31758
BarryKeymasterVery nice and thanks for sharing.
I do stuff like that too.
I have a Muff which is mostly a testing ground.
April 1, 2024 at 11:30 pm #31761peeeeeeej
Participantupdate:
now that i’m jamming on headphones and not on a very quiet practice amp, it seems that my 2k pot wired to R5 is controlling the bias (sound seems to get very velcro-ish when i reduce it) and the sag actually works great here imo. i changed the C1 mod to be 100n/10n and the bass reduction at 10n is really nice. still can’t wrap my head around the C3 toggle, it’s as recommended in the OKF doc (220n/22n) but i can’t hear the difference. anyway this thing is badass!
April 1, 2024 at 11:34 pm #31762peeeeeeej
Participantoh and when i said 2N3906 earlier i meant 2N3904
April 2, 2024 at 10:19 am #31769peeeeeeej
Participantfinal note for those following along: i replaced the 22n cap (for the C3 toggle) with a 2.2n cap and that further tightens up the bass frequency, so i would call this pedal a winner (and the R5 bias [presumably] control is a very happy accident that makes this thing super flexible).
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