Hi guys, I've got a mid nineties fuzz face reissue that stopped working at the weekend - I came across this forum while searching for info and thought maybe one of the guru's here might be able to help me work out what might've gone wrong with an eye on repairing/improving it? It's a pretty simple circuit and I figure if I can fix this I can move on to building my own stuff next...
It was a pretty hot day here so I don't know if it the transistors overheated and fritzed out or what, but when i turn it on now it passes un-fuzzed input straight through but adds a bit of hiss and general noise.I had been running it after another fuzz so maybe the high gain going in to it didn't help? not too sure about that situation...
anyway, I've opened it up and nothing looks burnt out so any help or suggestions will be much appreciated
broken fuzz face?
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The DIY forum is for personal projects (things that are not for sale, not in production), info sharing, peer to peer assistance. No backdoor spamming (DIY posts that are actually advertisements for your business). No clones of in-production pedals. If you have concerns or questions, feel free to PM admin. Thanks so much!
The DIY forum is for personal projects (things that are not for sale, not in production), info sharing, peer to peer assistance. No backdoor spamming (DIY posts that are actually advertisements for your business). No clones of in-production pedals. If you have concerns or questions, feel free to PM admin. Thanks so much!
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Scruffie
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Re: broken fuzz face?
Running a fuzz into a fuzz wont break anything so that's fine.
Is it one of the germanium model Fuzz faces? or Silicon? I ask because Germanium transistors are temperature sensitive although i've never heard of a hot day breaking them, I suppose it is possible.
Got any pictures of the inside so I can have a look for anything glaringly obvious?
The only other thing I can think of is that the transistor bias has gone off... which means you'd need to replace the 2nd Transistors collector resistor with a trimmer and then adjust the collector to between 4.5 & 7V or untill it sounds good.
If you wanna start on your own stuff here's some good links
Technology of the Fuzz Face, Required reading for messing with a fuzz face http://www.geofex.com/article_folders/f ... fftech.htm
Schematic reading http://www.beavisaudio.com/techpages/Sc ... ToReality/
Is it one of the germanium model Fuzz faces? or Silicon? I ask because Germanium transistors are temperature sensitive although i've never heard of a hot day breaking them, I suppose it is possible.
Got any pictures of the inside so I can have a look for anything glaringly obvious?
The only other thing I can think of is that the transistor bias has gone off... which means you'd need to replace the 2nd Transistors collector resistor with a trimmer and then adjust the collector to between 4.5 & 7V or untill it sounds good.
If you wanna start on your own stuff here's some good links
Technology of the Fuzz Face, Required reading for messing with a fuzz face http://www.geofex.com/article_folders/f ... fftech.htm
Schematic reading http://www.beavisaudio.com/techpages/Sc ... ToReality/
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Clearscreen
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Re: broken fuzz face?
First up - thanks for the reply! Looks like I've got some reading to do...
here's some pics of the guts of the thing
I couldn't spot anything that I thought looked wrong, but I'm no electrician so any help is welcome! I'll see what info i can find about the resistor bias idea as well
here's some pics of the guts of the thing
I couldn't spot anything that I thought looked wrong, but I'm no electrician so any help is welcome! I'll see what info i can find about the resistor bias idea as well
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Clearscreen
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Re: broken fuzz face?
Ok - just done some reading and I think you're suggesting replacing the 8k2 resistor (bottom of the three central grouped resistors?) in this image with a trimmer? Is there any point in replacing it with a pot I can mount through the body? How much difference would this make to the sound? I'm tempted to add a voltage sag pot as it is, so if the drills out I might as well make two holes if it's a useful mod... [EDIT - did a bit more reading and it sounds like adding a bias pot is a good thing?!]
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Scruffie
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Re: broken fuzz face?
Yup adding a bias pot is no different from adding a trimmer it'd just be external, I would suggest that you test it first though before you go drilling 
but that should work fine and if anything could help your unit sound better than before.
but that should work fine and if anything could help your unit sound better than before.-
Clearscreen
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Re: broken fuzz face?
Thanks for the help Scruffie - looks like i have a bit of learning and experimenting to do from here - I'll let you know how it goes!
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Scruffie
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Re: broken fuzz face?
Okies cool, no problem
If it turns out to be another problem though a useful tool can be found here in this debugging page other than the info stored on debugging a pedal it has a DIY audio probe which although simple can be invaluable http://www.diystompboxes.com/wiki/index ... =Debugging
If it does turn out the Germaniums are shot I can probably sort you out with some fresh ones aswell though so keep me posted
If it turns out to be another problem though a useful tool can be found here in this debugging page other than the info stored on debugging a pedal it has a DIY audio probe which although simple can be invaluable http://www.diystompboxes.com/wiki/index ... =Debugging
If it does turn out the Germaniums are shot I can probably sort you out with some fresh ones aswell though so keep me posted