Re: [linux-audio-user] noise from USB printer

Pieter Palmers wrote:

> Is the noise only present when printing, or also when the printer is
> idle?

Noise is there whether the printer is turned on or not. It disappears
only when one or another of the cables are disconnected.

> What you can do to test whether it is a ground loop is interrupting
> the ground connection of the power plug (e.g. by wrapping some
> non-conductive tape around the pin). If the noise stops, you have a
> ground loop. Don't use this as a solution to your ground loop however,
> as it is probably against regulations and is also pretty unsafe
> regarding electric shocks.
>
> If it is a ground loop, it is pretty difficult to solve. It's badly
> designed hardware. You could try to plug your printer into the same
> power outlet as the machine.

The printer is plugged into the same strip as the machine.

I tried lifting the ground, the noise was undiminished.

Next I'll try reprioritizing the interrupts, as soon as I can get
irqtune built. Or is there other software I should try ?

Linux 2.6 kernel, Debian Etch.

Best,

dp
Received on Sat Jul 22 16:15:05 2006