Reamp ground loop issue

fearhk213

Well-known member
Hey, you all. I'm brand new to reamping and have been getting some ground loop hum. The noise floor is of a similar volume level to plugging straight into the amp, but when I have it set up to reamp I get this underlying ground loop hum. I've exhausted everything I know to try, so figured I'd reach out here to see if any of you all have some suggestions.

Here's my signal chain: UA Apollo line out w/a TRS cable -> Signal Arts Reamp box -> instrument cable to front of amp -> guitar cab
My electrical signal chain: guitar amp & UA Apollo -> Furman Power Factor Pro -> Furman Voltage Regulator -> wall outlet
(I have a MacBook and don't have the power adapter connected while trying to figure this out since those adapter always add noise. I also unplugged my monitors from the Apollo and power source to eliminate that element).

Here's what I've done trouble shooting wise:
- I checked the wall outlet. It's grounded and the hot and neutral are on the correct side. Also, the Furmans typically read between 120v-122v, so nothing crazy there.
- The reamp box has a ground lift switch, which is engaged. It kills the vast majority of the hum, but there is still an underlying ground loop hum that it doesn't kill.
- I tried an Ebtech Hum Eliminator between the interface and reamp box using TRS cables. That actually made the noise worse.
- After the Ebtech Hum Eliminator failed to work, I called Morley/Ebtech today. They suggested I try a ground defeater plug on my amp. They said I should get the Hum Exterminator plug if the ground defeater killed the noise. I tried the ground defeater plug and it killed that last bit of ground loop hum - absolutely no different than plugging straight in the amp. I was totally stoked thinking it was solved. Well, I grabbed a Hum Exterminator plug today, and it doesn't do a bloody thing. I even tried plugging the amp into it and then straight into the wall, bypassing the Furmans to eliminate that variable. It made no difference.

I'm not really sure what to try/do next. It seems to be ground loop related since lifting the ground on the amp kills it, but maybe this is beyond the reach of what those Hum Exterminators can handle. Does anyone have any thoughts and/or suggestions?

Thanks!
 

midnightlaundry

Well-known member
I had a lot of noise in my system and it turned out to be a broken ground wire in the power cord of one of my monitors.. Crazy that all this time I thought is was a shitty mother board which it was NOT..

I'd switch all cords 1 at a time to rule that out.. Is everything plugged into the Furman?
 

fearhk213

Well-known member
I had a lot of noise in my system and it turned out to be a broken ground wire in the power cord of one of my monitors.. Crazy that all this time I thought is was a shitty mother board which it was NOT..

I'd switch all cords 1 at a time to rule that out.. Is everything plugged into the Furman?
Yeah, troubleshooting noise can make you want to beat your head into a wall lol.

I actually did try all different cords except for the power cord on the amp. Good call. I’ll try that.

Yes, everything is on the same Furman. I also tried going straight into the outlet to make sure the Furman wasn’t causing an issue.
 

fearhk213

Well-known member
Quick update:

I tried different power cables amps and another room & outlet with no luck. I may have found the culprit though. I think it's the interface.

Since it's a grounding issue I figured I could even eliminate the computer from the chain, so I just have the interface -> reamp -> amp/cab. With the interface & amp plugged in to the same outlet I get that hum as soon as I plug the interface in. It doesn't even have to be turned on. I forgot about an old interface I had laying around. I hooked it up the same way, and the hum was gone. I even turned it on to see if that would make a different. Still no hum. Unfortunately, it's old and they don't make drivers for the iOS I have. Everything is pointing at the interface now.
 
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