RG-16 / G-Force hum help?

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papadotas

New Member
I'm hoping someone can give me some guidance with a hum issue I'm having. I've tried a few things on my own, but I think at this point I need some expert advice. It's probably a ground loop issue--I don't think there's anything wrong with either the RG-16 or G-Force--but I'm kind of out of ideas right now.

I recently changed amps and ever since then, my G-Force has been humming loudly whenever I activate the RG-16 loop (Loop 7). Prior to this, it had always run quietly. My new amp is a Koch Powertone II, just in case that's relevant. Every other piece of equipment, including cables, remained unchanged and in the same locations; I just switched amp heads.

Here is some info as well as some things I've tried:

*G-Force is mounted to the rack with Humfrees, as is all other rack equipment.
*G-Force and Rg-16 are both powered from a Furman conditioner
*Hum is present only with the G-Force. I've tried some stompboxes (in the same loop) and there is no hum with them.
*I tried the G-Force in another loop (Loop 6) and there was still hum.
*There is no hum if I take the G-Force out of the RG-16 loop and run it directly in the effects loop (G-Force is the only thing in the loop)
*Hum is present when G-Force is removed from rack but still run through Loop 7
*I've tried other cables between the RG-16 and the G-Force and the result is the same
*Hum is present even when G-Force is powered off (but Loop 7 is active)
*I've tried an Ebtech Hum Eliminator between the Loop 7 Send/G-Force input as well as G-Force output/Loop 7 Return. In both instances the hum still remained and the signal sounded much weaker.


Thanks for taking the time to read this. Looking forward to any advice you all might have for me.
 
Strikes me that as it doesn't hum with stomp boxes in the loop, it is indeed a mains grounding issue as you suspect. Couple of thoughts - try mounting the G-Force to the rack without the hum-frees. They're not always the best way to go for everything. Alternatively, cut the screen at one end of ONE of the cables (but not both) to the G-Force from the RG-16. That would then only give it one route to ground, not two. If neither of these work, I'm stumped sorry! Guitar rig troubleshooting can drive you completely insane because sometimes it just doesn't make sense! I once (don't have either item anymore) had a problem with my RG-16 humming because it was too close to the PSU for my Whammy Pedal. I repositioned some items in my rack and it went away.
 
Another thing to try is a Hum-X - it's an a ground isolator for power instead of for audio. It would break any ground loops you're getting through the power connections.
 
Thanks very much for the replies.

Martin: I actually tried mounting the G-Force without the humfrees and there was no improvement. I also tried moving it to other positions within the rack but to no avail. Cutting the ground on one end of a cable sounds like something worth trying, though I'm not sure how to go about doing it. I feel at least somewhat fortunate that I know where the hum is coming from and can go from there.

Ron: I'll give the Hum-X a try!

Thanks again to you both.
 
papadotas said:
Cutting the ground on one end of a cable sounds like something worth trying, though I'm not sure how to go about doing it.
Click to expand...
Simply unscrew the barrel of the jack plug at one end, and either literally cut, or de-solder, the ground (the unshielded braided wire that's going to the outside connector - it's usually shorter than the main signal wire, which goes to the middle and will be wrapped in PVC). De-soldering it and wrapping a bit of electrical tape around the end so it doesn't make contact with the plug means that if it doesn't solve the problem, you'd be able to reattach it again easily. Thankfully 1/4" jack plugs are about the easiest things in the audio world to solder!
 
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