Dream Fuzz Issue
- Thread starter GRider22
- Start date
eaglehat
Member
Thanks for the quick reply! Looks like I got the 47ohms right.
The green chiclet 120nf I used was a tight squeeze and the corner is hovering very close to the center pin of the tone pot. Could that possibly be the issue?
Everything seems to work except for the presence of this oscillation which is always on.
(Just tried to upload a photo of the board, but the forum says the file is too big. I’ll try to resize and upload in a bit.)
The green chiclet 120nf I used was a tight squeeze and the corner is hovering very close to the center pin of the tone pot. Could that possibly be the issue?
Everything seems to work except for the presence of this oscillation which is always on.
(Just tried to upload a photo of the board, but the forum says the file is too big. I’ll try to resize and upload in a bit.)
Nostradoomus
Well-known member
Your 1uf electrolytic on the bottom left should be flipped around, best just replace it.
mikeperez83
New member
I'm actually having this same problem on the current revision. Built it and it worked like a dream, zero issues or noise. A few weeks ago i turned it on and there's this epic squeel coming through the pedal. the effect still works, but if i'm not playing the squeel comes right back. I've changed all the electrolytics, and the op amp(which is socketed), i also replaced the 3pdt, tested it with different power supplies and the Squeel still persists. i'm about to start pulling my hair out.
Did anyone ever solve this? I'm having the same problem, effect mostly works except for the loud squeal starting after R5 when the effect is engaged, regardless of signal input. I replaced R5 and IC1, no luck. IC1 seems to have the correct voltages (8.8v on pin 8, 0v on pin 4, 4.4v on the rest). My multimeter is reading a 60hz frequency in the signal path, so my only theory is there's some accidental crossover I can't find from the power circuit to the signal path.
Chuck D. Bones
Circuit Wizard
Does the squeal pitch change if you turn any of the knobs? We can't read C3 or C4, make sure they are the correct values. I do not recommend ceramic caps there, although ceramics would not cause the squeal.
The squeal is affected by the knobs (vol changes squeal vol, tone affects tone, sustain does it's thing), although the pitch seems to stay the same.
I re-rechecked that all component values are correct and properly oriented. C3 is a 4n7 and C4 is 10n. Thanks for the tip on not using ceramics there, I'll pick up some small film caps on my next parts order for future projects.
I re-rechecked that all component values are correct and properly oriented. C3 is a 4n7 and C4 is 10n. Thanks for the tip on not using ceramics there, I'll pick up some small film caps on my next parts order for future projects.
Chuck D. Bones
Circuit Wizard
The fact that the pitch is constant tells us that the squeal is NOT caused by coupling from output to input.
Have you tried a different power supply or battery power?
Your pic shows the board out on a bench, have you tested it installed in a box?
Are you using an audio probe to determine that the squeal starts after R5?
Have you tried a different power supply or battery power?
Your pic shows the board out on a bench, have you tested it installed in a box?
Are you using an audio probe to determine that the squeal starts after R5?
I've tried it in a metal enclosure, and through different power supplies, including battery and isolated psu, no change. Different amps, cables, no change. Also tried swapping the 4558 for a TL702, no change. It's a head-scratcher.
I did use an audio probe to identify where the squeal started. Could IC1 be amplifying an existing signal to create the squeal?
I think my next step will be to do a bunch of continuity testing to see if parts of the circuit are crossing over to where they shouldn't be.
I did use an audio probe to identify where the squeal started. Could IC1 be amplifying an existing signal to create the squeal?
I think my next step will be to do a bunch of continuity testing to see if parts of the circuit are crossing over to where they shouldn't be.
mikeperez83
New member
i'm having the same EXACT issue, not sure if its a board thing or not, i recently re capped and replaced the IC1 in my dream fuzz, it had been working perfectly and then one day decided it would do the same exact thing, loud squeal, no rhyme or reason. kept it on the bench and would play through it , worked perfectly, no more squeal, plugged it in again today, same damn thing again. its the 3rd pcb i've had odd unsolvable issues with.
