Header Graphic
Dirty-South Blues Harp forum: wail on! > Crackling noise coming from mic or pedal?!
Crackling noise coming from mic or pedal?!
Login  |  Register
Page: 1

Adam Pritchard
142 posts
Jun 28, 2024
4:10 AM
I've got a couple of vintage mics that when plugged directly into my amp sound fine, no crackling, but when plugged in via my pedal board I get a lot of crackling when moving or even touching the volume pot. I've isolated the problem down to the mics with specific pedals (my Lone Wolf Harp Octave, and my Squeal Killer anti-feedback). The crackling isn't there when plugging into my delay or reverb.

Anyone have any experience of the same issue? Could it just be the volume pot connections in the mic need a good clean or could it be the pedals themselves. Can you use contact cleaner safely on the inside of a pedal without damaging it? (I'm no electronics expert).

Many thanks for any help and support in advance.
Bruce S
57 posts
Jun 29, 2024
2:44 PM
Hi Adam,
I think with the Squeal Killer there's a -1V DC voltage on either the input or output, which could cause the crackle, as DC signal on a volume pot will do that. I'll have to get my home-brew SK clone and Harp Otave out and check if I get the same issue...
Bruce S
58 posts
Jul 01, 2024
2:18 AM
OK, so I checked my harp Octave and my SK with a Hohner HB52, and a JT30 with a CM element using my HarpTrain 10.
No problem with the Harp Octave. On the SK I measured a -0.4V DC voltage on the jacks and got audible scratching with the volume pot on the JT30, which has an Alpha mini pot. The HB52 had no discernable noise, but that has a sealed Bourns pot.
I suspect the problem is DC leak from the SK in combination with the cheaper Alpha pot in the JT30. Might be worth checking what you have as the VC pot in your mic and replacing it with a sealed Bourns pot?
Adam Pritchard
143 posts
Jul 02, 2024
2:20 PM
Interesting, thanks Bruce. I’ve tried it with 6 different mics. 2 have no volume pot so no crackling. The other four have volume pots but it’s only a problem on 2 of them. I’ve heard the connections can sometimes need a good clean with contact cleaner so I’ll try that first. Maybe something in the pedal is bringing out the problem but the problem isn’t the pedal itself. I’ll experiment some more but you might be onto something. I’m not savvy enough to be replacing volume pots though.
3721 posts
Jul 03, 2024
8:21 AM
Sometimes it can be caused by impedance mismatches between the mics and the pedals as well as dirty jacks, connectors, etc.
Barbeque Bob Maglinte
Boston, MA
CD available at http://www.cdbaby.com/cd/bbmaglinte
Roy Ale
3 posts
Jul 08, 2024
2:33 PM
Adam are you using a battery inside the lone wolf pedal or an AC power plug adaptor . i have had issues with a low battery that is inside my lone wolf pedal , so now i only use the AC power adaptor
Adam Pritchard
144 posts
Jul 11, 2024
11:46 PM
Thanks Roy, I’m using a 1 Stop power supply so no issues there.

Post a Message

(8192 Characters Left)

Modern Blues Harmonica supports

§The Jazz Foundation of America


§The Innocence Project




ADAM GUSSOW is an official endorser for HOHNER HARMONICAS