Originally Posted by Wolvers
Crikey you guys really know your stuff, thanks.
It is a 'fuzz' kind of noise from the tweeters.
Sounds like it'll be the Enermax PSU then as I'm getting it with TOSlink so there's no ground. It's not the amp as it was there with the Pioneer one I had before.
I'm surprised that an expensive PSU like the Enermax can produce something like this at all really, especially as the SkyHD doesn't. I'm as equally surprised that an expensive sound card like the HDAV can't 'clean up' this kind of thing although as my understanding of it is poor I may be talking utter tosh!
It could be some other bit of equipment, or another physical connection between the computer and the amp (HDMI, maybe?). My turntable is the worst offender in my setup.
You often don't have to select the offending input to hear the noise, sometimes if the signal is strong enough it will leak through to other channels on the amp - most amps have a common ground for all inputs, audio or video.
If I crank the volume high enough on my system I can always get a bit of noise, but it's less if I disconnect my computer and turntable from the amp.
Like somebody said before, though, the volume setting that I can hear this noise at would probably damage my hearing if I actually started something playing.
With all equipment there is a natural noise floor, even with no signal present - it used to be a lot higher than it is now, though. Older equipment (we're talking 70s analog) suffered from terrible noise even with nothing connected to any inputs, if you turned the volume up high enough.
EDIT: Thinking about it, are all your components connected to the same mains circuits, or are they spread accross several sockets in the room?