So a while ago my friend asked me to make him a fuzz-wah. I know for a fact I used a crybaby style wah for the actual wah part, but the fuzz... I can't remember for the life of me what the fuzz is based on. My friend let me look at the insides of it last night and I took some pictures of the fuzz board.
(https://i.postimg.cc/NKs0RJ8x/IMG-3001.jpg) (https://postimg.cc/NKs0RJ8x)
(https://i.postimg.cc/Yhf9GKF9/IMG-3002.jpg) (https://postimg.cc/Yhf9GKF9)
So it's obviously janky. However I do know it sounds amazing. Does anyone know what this could be based on? I can't read any of the capacitor values and I think I can faintly read the op amp is UA741
Oh the one thing I remember is the diodes are 1n34.
https://www.aaroncake.net/circuits/fuzz.asp (https://www.aaroncake.net/circuits/fuzz.asp)
Too open ended. You at least need the resistor values.
Maybe trace the circuit, add the part values you know. A skeleton schematic will help narrow things down.
How the drive pot is wired also helps.
The diodes look like 1N914's to me.
It could be: (these are output clippers as opposed to antonis' feedback clippers)
- the distortion/fuzz section from the Morley BFW fuzz wah.
- there was a Schaller fuzz circuit from the late 70's similar to the Morley.
- MXR distortion +/DOD Overdrive
- Is that a transistor on the PCB?
Maybe a Crowthers Hotcake? There's a few versions. Not sure off hand if one could be converted to LM741.
Quote from: Rob Strand on October 11, 2024, 05:00:35 PMToo open ended. You at least need the resistor values.
Maybe trace the circuit, add the part values you know. A skeleton schematic will help narrow things down.
How the drive pot is wire also helps.
The diodes look like 1N914's to me.
It could be: (these are output clippers as opposed to antonis' feedback clippers)
- the distortion/fuzz section from the Morley BFW fuzz wah.
- there was a Schaller fuzz circuit from the late 70's similar to the Morley.
- MXR distortion +/DOD Overdrive
- Is that a transistor on the PCB?
Maybe a Crowthers Hotcake? There's a few versions. Not sure off hand if one could be converted to LM741.
I'm working on a trace as we speak!
And yes that is a transistor on the board. I'm pretty sure it's just a buffer.
I'm guessing it's a Distortion+ if the diodes are germanium, or a DOD 250 if they are silicon. From the picture, it looks like the output from pin 6 goes to the diodes, and the diode pair are connected to ground (white wire going to pin 4 of the IC), which would likely make it one of those two.
Quote from: Mark Hammer on October 11, 2024, 05:40:08 PMI'm guessing it's a Distortion+ if the diodes are germanium, or a DOD 250 if they are silicon. From the picture, it looks like the output from pin 6 goes to the diodes, and the diode pair are connected to ground (white wire going to pin 4 of the IC), which would likely make it one of those two.
And I would agree with that, the only problem is that it sounds nothing like a distortion plus :icon_cry:
Looking at the bottom picture makes it look like its actually NOT connected to ground, but actually the adjacent capacitor.
(https://i.postimg.cc/F7C9Jjpf/IMG-3002.jpg) (https://postimg.cc/F7C9Jjpf)
Doesn't look like a distortion+ to me. I think antonis got it with the feedback diodes but I haven't confirmed it's an inverting topology or not,
Pretty much something like the top part of this,
https://www.next.gr/uploads/12/Fuzzbox-Using-LM7411.gif
[This variant from Elektor magazine, 1977,
https://www.freestompboxes.org/viewtopic.php?t=32015]
No doubt with some small differences with the biasing. Perhaps the opamp and BJT are biased from the same Vcc/2 supply.