First Pedal HELP - Fuzz Factory Clone - How do I fix?

Started by alexleebones, January 30, 2021, 03:06:59 PM

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alexleebones

I'm trying to build a Fuzz Dog Filth Factory Fuzz Pedal:

https://shop.pedalparts.co.uk/Filth_Fack_Crazy_Germanium_Fuzz/p847124_5439185.aspx

After putting the circuit together I try to test it and I just get a constant whining that changes pitch as I turn some of the pots, or disappears when I turn some of the pots all the way to the right so the effect is audible but with lots of crackling.

I tested the pots with a multimeter while they were still connected to the PCB and only the Volume and Drive seemed to be giving the correct readings (The value on the multimeter stayed the same as I turned the wiper.)

The other pots' values would decrease to 0 as I turned the wiper to the right (the leads were connected to the 2 outer terminals.)

I disconnected the pots and tested them again and this time they all gave the correct readings, the values on the multimeter stayed the same as I turned the wiper. So I don't think the pots are damaged or faulty?

The only other possibilities I can think of are:

1. It's a grounding issue, but I don't know where or how to fix it.

2. Bad soldering connections. Should I resolder every connection again?

3. I've already damaged the PCB/components with my shoddy soldering and I'm basically @#$%ed?

I took these photos after I reconnected the pots, you can judge for yourself: http://imgur.com/gallery/S2YMaUa

Any help or advice would be greatly appreciated. I'm pretty crestfallen that I've put time, effort, and money into this and it's all been for nothing.

PRR

Welcome!

Quote from: alexleebones on January 30, 2021, 03:06:59 PM...I just get a constant whining that changes pitch......

That *may* be self oscillation. Output leads too close to input leads. Like a mike in a PA situation, only electric fields. Then a picture of the *whole* build may be more telling than pot close-ups.

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idy

Welcome.
You picked kind of an unlikely candidate for trouble, the physical integrity of the pots. At least with off board wiring you were not as likely to destroy the pcb with the soldering iron. I would want to double and triple check the wiring though.

The Fuzz factory clone is supposed to oscillate and several pots can cause this. It is by nature an unstable and wild thing. It takes a bit of fiddling to get it nice, but the ones I have made had a pretty good range of "not feeding back." I had to put one or more pots all the way....

The soldering doesn't look too bad, its generally worth a reflow to make sure, but be careful not to over heart the trannies or the pots.

Are you sure about the pinouts on your Germanium transistors? The other one too.
Most of us, face with this project, would find data sheets for all three transistors, determine which lead is E,C,B, then test them somehow to make sure that's true. Not with the modern Silicon one, that one we might trust the data sheet, but there are surprises even there. And you cannot simply trust that the little picture on the pcb looks like the package your trannies came in....

Any chance you cooked one of those, especially the Ge ones, with the soldering iron? The instructions say heat sink em when soldering.

The instructions also say don't socket them; good advice if you are sure you have them in right and sure you like them. Dismal advice if this your first try or if you bought a kit because you hoped to tinker down the road...

eh la bas ma

#3
Someone sold me an original unit for 60 e ( instead of 260, I think). He thought it was broken and I thought so too, untill I watched a demo ! Crazy sounds, and  leaking transistor's noises, I love it.

The pitch of the leaking noises is supposed to change,and 3 controls interact a lot together (Gate, Comp, Stab). You can fine-tune the leaking very precisely with this fuzz, and play with it. I think it's really the most versatile fuzz ever .

I am trying to use a pot as variable resistor, and I learned the pot's values only change on the multimeter if you probe the middle and one outter terminal, leaving one outter pin alone. This test should answer the "faulty pot" question for good.
"One Cannot derogate, by particular conventions, from the Laws which relate to public Order and good Morals." Article 6 of the Civil Code.
"We must not confuse what we are and what society has made of us." Theodor W. Adorno.

iainpunk

if you use a pot as a variable resistor, its good practice to solder the unused pin to the middle pin, this will prevent it from picking up noise for some reason.

cheers, Iain
friendly reminder: all holes are positive and have negative weight, despite not being there.

cheers