On Sun, 2009-11-29 at 18:44 +0100, fons@xxxxxxxxxxxxxxx wrote: Are you plugging the devices into different outlets? Rich... > > How can I check if the keyboard/power supply is grounded? The power supply > > itself is a three pronged one.... > > Then in most countries it is required by law to be > effectively grounded. Next question is if you power > socket is... It should be if it accepts the plug. > > Since you also have this interference with an amp, > but not with the headphones it really seems to be > a grounding problem. > > To only other way to explain it would be to assume > it's some high-frequency stuff which your headphones > would just ignore, but any active input such the amp > or soundcard could demodulate into the audio band. > > If you're using a laptop, does running it on battery > make a difference ? > > Anyway I'd try a DI box, it's good practice anyway with > all instruments. > > Ciao, > _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
