I've had sound generated from the mouse pointer moving across the screen, but that went away (went down to an acceptable level) when I muted all the inputs that were unused.

Tor

Everything else is Firewire, the mouse is the only USB Device. I do have a Contour Shuttle that is USB but I haven't even pluged it in yet. The sound card is a brand new Echo Layla, and works fine with a PS2 mouse. The hum doesn't get recorded, it's just in the Monitors. The mouse isn't wireless, it's one of those portable ones with the retractable cord (thats probably the problem). Placement doesn't matter, it just hums when the optical light goes into sleep mode. I'm more curious to your success with your Logitech, I just don't want to buy another optical that hums to me. I figured it was a defective mouse but one of my buddies has the same one and when I tried his it was the same problem. I think I will try the Logitech, what model do you have?
Thanks, Mike

I have a Logitech optical mouse and it does hum a lot in the Aux channel. I muted the Aux channel and lost the hum, but I think it's curious that a mouse would cause sound at all. It didn't used to happen and I don't know when it started, but I'm glad to be rid of it because it was really annoying.

Tom

I have a USB optical "Explorer Trackball" by MS. I use the USB/PS2 adapter.
This uses an IRQ, so to compensate, I disable the Parallel, Serial, onboard joystick and MIDI ports in the bios....as well as keeping ALL unused USB devices unplugged.
You might be a candidate for any USB Filter patches available from your mobo or chipset manufacturer.

I will try switching the pointing device back to USB and see if I get this as well.

Interesting.....

A million years ago I remember getting a hum whenever I moved the mouse. Turned out to be one of the connectors on the back was loose.

Slightly unrelated, but this does give you an idea of the oddness of these problems ...

When i connect my sound card's line output to the amplifier at home, i get a nasty hum in the speakers when i close the CD-writer drawer, but not when opening it, and the DVD drive drawer doesn't make any hum. When i bring the computer in to work and connect it to the amplifier there, no hum. Go figger.

Chienworks

Are you connecting your amplifier to the same outlet as the computer, or is it another one? If the Amp is connected somewhere else you may be getting an earth loop (current looping around the slight potential difference in the earth cable) this causes Hum, the Mechanism of the CD draw may be changing the earth path. Try pluggin in the Amp at the same point as the PC.

DrWho: both the computer and the amp are on the same circuit both at home and at the office. And yes, i've tried with ground lifters and without; same result. I have yet to try a different circuit though. Hmmm. Maybe the home amp wants to be grounded directly to the computer case. Seems like the audio patch cable would be doing that already, but i can try a hard ground and see what that does. Possibly i need a transformer coupled cable to make sure there's no common ground. Of course, since this only happens when i close the CD-writer's drawer, which i probably only do a few times a day at home and it only lasts for about 2 seconds, i'm not particularly worried about it.

Electrically speaking, the inside of a computer is a very noisy place. The analog audio cable that runs from the CDROM to the input of the soundcard is rarely of particularly high quality and it is susceptable to picking up all kinds of junk. The digital signals from the various computer components are all square waves, which are extremely rich in harmonics. The CDROM audio cable is just like an antenna.

In the case of the original mouse-related noise question, depending on how the audio cable is routed through your computer, it may be that it is picking up some interference from a piece of circuitry that is active when the mouse is being moved.

In general, you should always mute any soundcard inputs that you aren't using, particularly the CDROM input because of what I just described. You should also mute the microphone input because of its high gain and it's relatively noisy all by itself.

John

All that is true... but sometimes it is unexpected things. A few years back I had hum and it was driving me crazy, because it happened whenever I moved my trackball, so almost constantly. After checking all the usual stuff and even replacing the trackball, (good excuse for a new one) it turned out to be one of the wires inside the keyboard wasn't connected as tight as it could be.

Just recently, I had hooked up the output from my MIDI/audio rig to the PC souncard, and had the most god_awful hum/buzz. I put one of those "3 prong-to-2 prong" ground lifter adapters on the MAIN power plug for the Audio rig......Pure silence!

btw,I did try the USB mouse switchover from PS2, to see if I could replcate the mouse humming. No hum....whistling...or singing(talk about an untalented trackball).

I don't think you even need those little audio cables from a CD drive to be connected to the soundcard. I can play audio CD's from both drives no prob. You may want to use the 2 pin spdif connecton if applicable.