Computer line into soundboard

[DannLea]

Hey everyone,
I am running a computer and have it wired into an Allen & Heath soundboard to run audio from my PC into the soundboard and into the PA system.

The issue is, it seems like there's an uneven ground somewhere along the line. When recording audio on the computer, I have an annoying "hum" going through.

I have the lines run through hum busters, and there's still no luck. The hum prevails.

But here's where it gets fishy.... If I take all the lines and route them into my unplugged laptop rather than the tower, the hum is gone when I play/record audio.

This leaves me to assume it is a ground problem, and so I have a few basic questions.

1. What's the worst that can happen if I "de-ground" the computer plug in? If there were a fire, would doing so null the fire insurance?

2. If the first question is a no-no, how can I practically solve this problem? I don't have enough cash to run through and rewire the whole place, and I really am unsure of where the problem is originating. I need a "cheap-fix" for lack of a better term.

Hopefully someone here knows!

Thanks,
Dan

 

[Fallen Kell]

Try changing the outlet your PC uses. If it is really a ground loop, it is typically one of two things. Either your equipment spans across multiple breakers in the electrical design (and they did a poor job grounding and/or used different grounds on the different circuits), or a particular outlet has a bad ground. Changing what outlet you use on the piece of equipment you suspect as having the bad ground can fix the problem.

The only other solution is to only connect the PC via optical SPDIF in which there is no electrical connection between the PC and your sound board (but that may not be possible with the equipment you have).

 

[DannLea]

Try changing the outlet your PC uses. If it is really a ground loop, it is typically one of two things. Either your equipment spans across multiple breakers in the electrical design (and they did a poor job grounding and/or used different grounds on the different circuits), or a particular outlet has a bad ground. Changing what outlet you use on the piece of equipment you suspect as having the bad ground can fix the problem.

The only other solution is to only connect the PC via optical SPDIF in which there is no electrical connection between the PC and your sound board (but that may not be possible with the equipment you have).

Okay, I've re-hooked the computer into a wall outlet about 10ft away from the original one. Still have a problem. As for the optical SPDIF, I'm using a computer with standard 3.5mm jacks and the soundboard is an Allen & Heath analog board. I don't think there's any way to plug the computer direct into the house sound without neglecting the soundboard altogether, and I definitely can't do that.