background noise heard through speakers

[VirtualLarry]

I plugged in a cheap pair of iMicro speakers, they have a headphone plug, and a USB plug. They plug into a regular audio output, but have a USB power interface.

Well, in my desktop rig, you can clearly hear electrical noise through them. I assume that's just noise in the USB power, leaking through the power supply. You can hear when the screen is doing things, and moving the mouse, etc.

A pair of headphones plugged into the same front-panel audio jack doesn't reveal any background noise.

So I'm pretty sure that the noise is on the USB power wires, not the audio ports.

Any ideas? Is this dangerous to any of my components?

 

[superccs]

This is referred to as groundloop interference I think. I get the same thing when I have some USB devices plugged in. There are devices that you can plug in inline that eliminate this noise.

Check out this site:
http://www.epanorama.net/documents/groundloop/
There is a bunch of info there.