ground loop problem

[Jakeman1086]

I did not have this problem before with this exact same setup and a different desktop computer. I just switched the desktop out for a new one, and now I have a ground loop. The picture represents exactly what my setup consists of right now.

I have high frequency "chirping" noises coming from the speakers that tend to react to mouse clicks and cpu activity. I completely solved the problem by inserting an IMP2 DI Box http://www.whirlwindusa.com/dirbox.html#imp2 in between my audio interface and the studio monitor. The volume was significantly reduced and I think I might be losing high frequency content though.

I'm thinking the problem is interference between the CPU and the firewire connection which are very close to each other on the motherboard. Dunno.

Plugging in the AC adapter to my Presonus firebox interface significantly reduced the noise but did not eliminate it.

Right now, I'm thinking 1 of 4 things:

Option 1 - buy high quality firewire cable ($40)
Option 2 - buy firewire PCI card ($50-60)
Option 3 - buy Ebtech Hum-X ($60)
Option 4 - buy two DI Boxes and two XLR cables and insert them between the audio interface and the speakers. (Will this reduce sound quality?)

Please help me!!

 

[Farno]

From what I've heard, the Hum-X works very well but I've never used it myself.

I think, but I'm no expert at this, that in order to have a ground loop you need 1 thing plugged into a outlet, and another plugged into a different outlet. But those 2 things needs to be connected (such as an amp and a computer). You've got them plugged into a powerstrip and I'm not sure if that causes a ground loop but if you've got one, then it must be.

If it was the power strip, I'm not sure if the Hum-X would help you. If you plug your powerstrip into it, you're not actually cleaning up the area unless there is something else plugged in the room on a different outlet that is connected to you're setup...

Not really sure if I'm correct so don't take my word.

 

[Rod Gervais]

Jake,

if everything is hooked up the same as before - the only difference is the computer - then the problem is not a ground loop (which can only be caused by ground going to 2 different locations - which creates the physical loop).

This problem might well relate to bad grounding inside of the computer chassis - but you should not be taking a brand new computer and start screwing around with it.

I would contact the computer manufacturer and inform them of the problem their equipment introduced to the system -

Again - nothing magically changes with the grounding in your room - this is an equipment issue - not a ground problem.

Rod