> > Do you hear the same noise with headphones in the Sound Blaster card and > > all other outputs/inputs disconnected from all cards? > > No!! The noise goes away completely (and I get good signal levels)! Cool. I guess the Audiophile is more tricky to get headphoned.. (I have it too) > > I suggest that you take your electricity for the computer and amplifier > > and all that get's physically connected to them from one grounded outlet. > > And beware if you have antennas connected to the system, they give ground > > loop humming also. > > I tried putting everything on the same power strip and I still get the > noise. I have a mixer and an amplifier that the signal is going > through, and I get the same noise going: Then you should have all the equipment physically connected to each other from their cases, like grounding them together. ** BUT BEWARE, THIS MIGHT BE DANGEROUS. ** I don't know where you live, but in Finland the electricity system is pretty darn safe and I wouldn't have any hesitations to do so. There might be high voltage differences between the cases, so all equipment should be disconnected from the outlet before grounding them together. And take life insurance first :) And don't sue me if something blows :) Previously I had my gear in non grounded outlet and found out that the voltage difference between my aplifier and computer case was around 240V, but only for a fraction of a second because they got grounded together as soon as they got physically connected throuhg the voltmeter. Of course the current was not much so it was not lethal, but gave some nice snaps at your fingers if you touched both. Then I got a grounded outlet and the problem disappeared. Unfortunately my aplifier doesn't have a grounded electricity plug, so it still grounds through my cables, but the common ground is now same as the real ground, which was not the case previously when the common ground was 'floating'. BUT, if I have my vcr and radio connected to the amplifier, I hear the humming noise at high volume levels. It doesn't bother in low volumes, but if I were to record something, I'd plug out the antennas first. No antennas -> completely silence. Just make sure that all that connects to your computer (usb stuff, firewire, monitor, etc.) don't cause the noise. Try plugging out all of them. > > It appears to be system load based, it might be an internal voltage > > interaction when your CPU goes from idle to active. I've seen > > this before..... try to run this at a bash prompt: > > while true; do yes > /dev/null ; done > > This takes away a large part of the noise. There is still some noise > that sounds different, and I can still hear my mouse move. When I move > my mouse vigorously, it starts sounding closer to what it sounds like > when that shell script is not running. Try different PCI slot. But my guess for the mouse noise is the graphics adapter. I remember in the old days with SBPro, that I had to choose ISA slot that had the most distance to the graphics adapter, and still get some high pitch whining. If it was closer, it got louder. Do you have some motherboard integrated thingy or some real AGP card? Tommi ps. Currently my amplifier is at recording studio and all I have is this crappy portable cd-cassette-radio boombox. It has only mic input with a 3,5mm miniplug. It gives me high whining noise and I can hear only the left channel. And I'm ought to do some drum track editing due monday.. :(
