I had initially tried reseating and replacing the soundcard (an Audigy 2 ZS Platinum Pro) as you suggested vapilot, but this made no difference. I do not believe it is a soundcard issue, as I (perhaps foolishly) tried to remove the PC from the loop by simply touching the front speaker connector to the metal surround of the printer USB cable - the noises did occur.
However, the noises were not present when I attempted the same with a pair of headphones...and the rear/centre/sub speakers are not affected as they are on a seperate amplifier (I made an error in my initial posting, stating that all speakers were affected. This was not the case, as it turns out).
The PC was home built by myself and as far as I could tell, there are no shorts, bad grounds, et cetera within the case wiring. This seems irrelevant now however as I can make noise occur without the use of the PC, as above...
I am now unsure of whether I have :-
- A strangely sensitive amplifier for my front speakers. Two Tannoy Mercury speakers connected to an aging but still good sounding Audiolab 8000A.
- A mains supply issue. It would be impractical as of now to try to connect the amplifier or the printer to a different mains supply - they are both on the upstairs ring.
To be honest I'm stumped completely. No other USB devices I have cause this issue. I might just have to stump up the £30 for a print server and give up
