Groove Harder Posted May 11, 2020 Share Posted May 11, 2020 (edited) Hi, Looking for some guidance here. My father passed on his Big Muff for me to have a look at as there is are loud whine whenever there is power to the pedal. This happens with both mains and battery. You can hear the effect through the noise although not in the video. Does anyone have any idea what may be causing this problem? Cheers cameringo_20200511_232657.mp4 Edited May 11, 2020 by Groove Harder Quote Link to comment Share on other sites More sharing options...
Bigguy2017 Posted May 12, 2020 Share Posted May 12, 2020 Sounds like some high speed motor boating is going on. One of the op-amps oscillating? Suggests decoupling caps are faulty (or op-amp is blown). Check the soldering for dry joints (big cap bottom left corner in the underside looks a bit blobby). Gently wiggle the cables... any crackles? Lift one leg on the caps (green ones and electrolytics) and put a cap tester on them. Otherwise you need a 'scope and follow a signal through. 1 Quote Link to comment Share on other sites More sharing options...
Groove Harder Posted May 12, 2020 Author Share Posted May 12, 2020 I'll check that out, cheers dude 👍 Quote Link to comment Share on other sites More sharing options...
Groove Harder Posted May 13, 2020 Author Share Posted May 13, 2020 It was the RC4558! Replaced and working a treat. Cheers once again pal 👍 Quote Link to comment Share on other sites More sharing options...
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