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Hoffman Amps Forum image Author Topic: Wah-wah that hums - Ground loop?  (Read 8299 times)

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Offline dude

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Wah-wah that hums - Ground loop?
« on: August 18, 2011, 11:53:49 am »
Nothing but the Wah wah pedal and it hums, take it out go straight to amp, quite.

I read about a ground loop but don't know the fix with a pedal.

If I turn the pedal off, no hum.

Any suggestions? I did search and found the ground loop could be causing the problem.

But the fix?

thanks,

al
If it ain't broke, don't fix it.

Offline sluckey

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Re: Wah-wah that hums - Ground loop?
« Reply #1 on: August 18, 2011, 12:37:51 pm »
Does it hum regardless of which amp it's connected to?
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

Offline dude

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Re: Wah-wah that hums - Ground loop?
« Reply #2 on: August 18, 2011, 11:50:11 pm »
Yes any amp, alone or with other pedals in a chain.

It's definitively the wah-wah pedal if I leave the wah off no hum.

I play an 18 watt Trinity SIII TMB, which plays great no hum alone or with these three pedals, strat into a Boss CS-2 compression, then Ibanez TS10 (modded to 808 specs) and sometimes an Ibanez GE10 EQ. I just started to try the wah-wah and put it first in the chain.

Just the strat and wah and it hums too, no other hum with any of the other pedals just when I add the wah in the front.

Thanks,

al
If it ain't broke, don't fix it.

Offline VMS

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Re: Wah-wah that hums - Ground loop?
« Reply #3 on: August 20, 2011, 09:25:41 am »
What wah-wah pedal are you using?

Is it powered with battery or a power supply?



Offline dude

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Re: Wah-wah that hums - Ground loop?
« Reply #4 on: August 20, 2011, 09:41:20 am »
Crybaby, from the late eighties or early nineties.

Model GCB-95,  made in USA

external power supply at 9.45v dc

Thanks,

al
If it ain't broke, don't fix it.

Offline VMS

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Re: Wah-wah that hums - Ground loop?
« Reply #5 on: August 20, 2011, 10:12:37 am »
Try and see what happens with battery.


Offline dude

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Re: Wah-wah that hums - Ground loop?
« Reply #6 on: August 25, 2011, 04:26:48 pm »
Sorry for the long delay getting back, I didn't have a good 9 volt and kept forgetting every time I went out.

Anyway, Bingo works great no hum at all.

So I guess I'm limited to a 9 volt for the wah?

thanks,
al
If it ain't broke, don't fix it.

Offline sluckey

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Re: Wah-wah that hums - Ground loop?
« Reply #7 on: August 28, 2011, 08:52:43 pm »
Maybe get a better power supply.

My old Thomas Organ Cry Baby works fine with my power supply and it was never meant to be used with anything except a battery.
A schematic, layout, and hi-rez pics are very useful for troubleshooting your amp. Don't wait to be asked. JUST DO IT!

 


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