[linux-audio-user] noise from USB printer

Mark Knecht markknecht at gmail.com
Fri Jul 21 20:29:24 EDT 2006

Ground loop problem? As a test only, what happens if you unplug power
on the printer, or turn the printer off?

If it is a ground loop issue - I did hear of this recently with a USB
hard drive I think - then possibly it's a cable issue or maybe you
could stuck a USB hub in the middle to break the loop? (Just
guessing!) ;-)

On the off chance it's something more nefarious, what are the relative
IRQ priorities of the USB controller vs. the sound card? I Assume the
sound card's IRQ has a high realtime priority? If not, and it's lower
than USB, then possibly there is some strange interaction. I've never
run into anything like that with USB, but I have with other devices
like a mouse, etc.

Hope this helps. (not holding my breath!) ;-)


On 7/21/06, Dave Phillips <dlphillips at woh.rr.com> wrote:
> Greetings:
>   I hooked up my new HP 6540 printer today, it's a beauty, but it
> creates a terrible noise through my speakers when it's running. Is this
> a known problem with USB devices ? Is it a mobo problem ? (This is
> happening on my old 800 MHz machine.)
>   Short of disconnecting the cable when the printer isn't being used, is
> there a solution to this trouble ?
> Best,
> dp

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