Too much noise when USB connected

I know the Procyon makes noise when batteries are low.

But Im noticing that when I connect it to USB, and use the Audiostrobe setting, the unit makes a VERY uncomfortable noise in the background, even if I mute the PC sound card.

It works fine when I use the Procyon in integrated session mode and USB.

Any advice? Defective equipment?

Hi OmiH;

If you are using the same PC for the audio source AND USB power, then you probably have what's called a "ground loop".
If you run the Procyon on batteries, but use the PC for the audio source, does the noise go away?
If so, then it's definitely a ground loop.
Is the PC a notebook computer? If so, try running it on batteries to see if that helps.

-Andy.