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 Quadrafuzz hum & noise issues 
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Joined: Wed Jan 06, 2010 1:33 pm
Posts: 3
Post Quadrafuzz hum & noise issues
I just got hold of a quadrafuzz that was already built but not very well. There was some suspect dry joints and the 4016 switching IC had died (which i replaced with a 4066 which seems to work fine) but after fixing all that up i'm still getting some issues with hum and noise, and was wondering if anyone could help.

There is always a certain amount of 50hz mains hum which for some reason seems to get stronger when the unit is actually sitting on or near my metal work table. I'm thinking this might be down to needing shielded cable for some of the audio connections so i'm not that concerned about that at the moment. Whats annoying me is that there are two low hums happening. One is obviously a mains hum but the other is a slightly higher frequency and mysteriously disappears whenever i play anything bass heavy through the unit. Then after exactly 7 seconds it comes back again :?

I'm thinking it must be something to do with a cap discharging but i can't find out for the life of me what it is. I've already replaced the power supply caps and regulators. The wiring on this thing isn't brilliant and could probably do with being completely redone but this doesn't seem like a wiring problem to me. I've tried running it on both AC and DC but it made no difference.

Other wierd things include one LED from both of the mid bands not lighting up as much as the other on each band, and the attack knob going up to about 3'o'clock and then the second it goes past that point the gain is boosted massively and you get instant hum and feedback. I've cleaned the pot but its made no difference and it doesn't feel like a dirty pot issue.

Any help would be hugely appreciated. ;)


Wed Jan 06, 2010 2:11 pm
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Joined: Sun Nov 09, 2008 2:49 pm
Posts: 726
Post Re: Quadrafuzz hum & noise issues
Hello Crustypaul.

I have copied this message and posted a reply to it over in the Q&A section.

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Scott Lee
scott@paia.com


Wed Jan 06, 2010 5:58 pm
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