reamping electrical noise help

[madbutcher]

I am doing my first reamping in the new place. I have 2 different electrical circuits. one has all my audio stuff and computer, one has nothing on it. if i plug the signal from the reamp into the guitar amp while the amps are powered on the same circuit as the computer, i hear the computer processing noise and some hum/buzzing in the amp. if i power the amps on the circuit with nothing i get an even worse hum/buzzing but no computer noise. A guitar plugged in makes only the little hiss of the amp (its an orange on high gain).

I'm getting its some ground loop problem right? the reamping is creating a loop. But how do I solve it? Will this ebtech thing fix it? http://www.sweetwater.com/store/detail/HumX if so wheres the right place to put it? the pc/audio power or the amps power or both? Or is the hum eliminator that goes through the guitar cable better?

 

[B36arin]

Have you tried lifting the ground between the reamp box and interface?

 

[madbutcher]

Yes, and that removes a good chunk of low hum. but there still seems to be noise from the PC in the one circuit, or a slight buzzing in the other.

 

[Delitzsch]

Some audio interfaces have grounding screws on the back. Maybe you could try that. I've never personally done it, but just throwing a suggestion out there.

 

[deLuther]

If reamp box is passive (transformer based), it should remove any ground looping problems with ground disengaged, there is no need for additional isolation device...
Some example illustrating the problem will be helpful.

 

[madbutcher]

yes it is a passive box (radial JCR) with ground lift switched on. I noticed also when I hook ANY pedal into the chain it produces a buzz noise. Getting more confusing.....

 

[deLuther]

Pedals powered from battery or external power source?

 

[madbutcher]

well i thought i had solved it by running a TRS-XLR cable (TRS in focusrite line out XLR in on the reamp box) instead of just a TR cable as I had been doing.. But i went back to the TR cable to check and no noise was there. even with pedals. It all definitely has to be on the same circuit, that is for sure. So I am a little lost but at least I have it pretty much working.... except that computer noise can be heard. like if I minimize a window i can hear it make a noise on the amp.... I am hoping something will stop that. Ground is lifted on the reamp box. will powering the amp or the computer through a power conditioner filter out that computer noise?

 

[jeid]

What computer are you using? Any chance it's an iMac?

 

[mickrich]

TRS should remove computer jitters.
TS will also give you a low signal level to your reamp box.
If TRS doesn't remove computer noise, an art dti should do the job
http://artproaudio.com/artcessories/audio_solutions/product/dti/