[LAU] USB audio interface and a buggy USB controller

[david]

Alex Tinsley wrote:

> First off any noise that you hear through your USB Audio interface is 
> because the grounding in the audio device is using the grounding on the 
> laptop which is most commonly data ground wired to earth ground. So you 
> hear all computer noise through the audio output. One way to alleviate 
> this is to lift the ground on the laptop (unplug the power adapter from 
> the laptop or get a ground lift adapter). Noise goes away. A lot of 
> devices suffer from this, 1394 has same issue.

I only get noise on my USB soundcard when I plug it into my external 
hub. I get no noise with it plugged directly into the laptop. I guess 
the laptop ground is OK and the external hub's ground is junk.

The hub has other devices plugged into it, I don't recall if I tried 
using it with only the soundcard. Wouldn't be surprised if some of the 
other USB devices on the hub (scanner, printer, MIDI interface, 
PS/2<>USB adapter for keyboard & mouse, flash card reader) are sources 
of noise by themselves.

Thanks for the extensive info!

-- 
David
gnome at hawaii.rr.com
authenticity, honesty, community