Parentheses mini fuzz only half working

JulienD

New member
Hi everyone,

I've contemplated building pedals for a long time, but took the plunge only a few weeks ago.
My first two (simple) builds went smoothly, but I ran into my first non-working build yesterday with a Parentheses Mini Fuzz, that is in fact half-working.

The bypassed signal is normal, and the boost side works perfectly, but the dist side doesn't.
I only get a very feeble amount of signal bleeding through a lot of white noise with all pots maxxed out.
I therfore assume that the issue doesn't reside in the power supply or jack in & out wiring, but most likely in the pcb, footswitch or pots wiring.

A few observations of interest:
- I don't have an audio probe (and won't have the parts to build one for at least another week or so), but I have a decent DMM.
- Offboard wiring and dpdt lug solder joints are ok, as evidenced by continuity tests with the DMM.
- The signal reaches at least the first components, but I can't test caps, diodes or transistors with a DMM.
- The IC is installed the right way, and so are the transistors (although I have no way to make sure they are spec-compliant).
- I've tried to switch them around (one by one, obviously), just to make sure the right orientation was specified on the PCB, to no success. It only makes a difference for Q5 (the last transistor before the volume pot, so post-IC and post-clipping); the white noise that I had with all pots maxxed out is now gone, but the small amount of guitar signal that was bleeding through is still audible, which leads me to believe that it comes from somewhere else than the intended signal path.
- Interestingly, the signal must reach at least as far as LED D6, located in one of the two clipping branches (and therefore post-IC), since it ligths up when I hit the strings.

So my questions for you guys are:
1) does the description of the issue and/or picture of my build ring a bell for some of you ?
2) how would you proceed from there?

Thanks a lot in advance!
 

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Hi, I have the same kind of problem.
The distortion side lets a clean signal through without any distortion but the octave side works. The PF5102s were replaced by 2N5457s and I was wondering if this could be the problem. Should I replace them with 2N5458s?
 
Hi, I have the same kind of problem.
The distortion side lets a clean signal through without any distortion but the octave side works. The PF5102s were replaced by 2N5457s and I was wondering if this could be the problem. Should I replace them with 2N5458s?

Does the tone control do anything? The jfet is just a unity gain buffer so it sounds like that is working. What kind of opamp did you use and where did you get it?
 
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