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Motorboating Fuzz Face


 
8/4/2003 6:13 PM
Kerry M
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Motorboating Fuzz Face
Just plugged in my first homebrew FF clone and was greeted with a low, flatulent *motorboat* oscillation when the fuzz control is all the way up. I could dial it out by turning down the fuzz, but as it is turned up a octave-down type of oscillation is heard. I'm using Ge trannys from smallbear and the PNP, neg ground layout from JD Sleep. Below is a link to a PDF of my perfboard layout. If anyone spots any obvious bonehead errors, or if this problem is familar, I'd appreciate any info.  
 
Kerry M  
 
http://home.earthlink.net/~kmax58/ffperfboard.pdf
 
8/4/2003 7:29 PM
Skreddy
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Other than the fact that your 470 ohm resistor is wired wrong (take your -v and tie it to the junction between the 33k and the 470R), I don't see anything obvious.  
 
I usually end up putting a small (100R - 200R) resistor in series with the fuzz capacitor (your 22uf) because a squeal is common at full fuzz rotation. Try replacing that 470R resistor with a (correctly placed) 2k (trim)pot; you can tune things in better.
 
8/5/2003 6:49 AM
Kerry M
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>Other than the fact that your 470 ohm resistor is wired wrong...  
 
Sorry about that- the pdf was incorrect there (pdf updated). I have the correct connection on my actual board. I was prepared for high pitched squeal, but not the low frequency oscillation I'm getting. Back to the drawing board I guess.  
 
Kerry M
 
8/19/2003 6:11 AM
Kerry M
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Re: Motorboating Fuzz Faced - fixed
Actually I just started from scratch and built it PNP/pos. ground, after I decided to only use it with carbon batteries. Works great! Great *early Jimi* tone. Next is a homebrew Rangemaster.
 
8/20/2003 5:31 PM
Skreddy
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Thanks for the update. So what did you change, if anything? Did you follow the classic FF schematic exactly?
 
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