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Discussion Starter · #1 ·
I am getting really annoyed. Mainly at myself, since I cant remember when precisely I started hearing this.


I hear the HDD chatter, the DVD-ROM spin up, and the cordless trackball when I move the mouse cursor. If I hold down a key on my cordless keyboard, I can hear that too, sounds like a very quiet machine gun. At all times there is a wavering high pitched squeal. All this is noticeable at moderate volume levels.


I use a Hercules GTXP for sound. I have a ATI TVWonder tuner card, a generic NIC. GF3 for video, projecting with an LT150. The PC is in a custom enclosure in my attic/crawlspace. The DVD-ROM drive is external to the case on a 36" IDE cable. There is a great mass of black spaghetti strewn all around the PC, coming in from CATV, various peripherals, and going out to the projector, speakers, bass shakers etc. In short, a trouble shooter's nightmare.


Things I have already tried that didn't help:


*Disconnecting ALL peripherals except GTXP, projector and keyboard. The only thing connected to the GTXP rack was the speakers.

*Disconnecting CD-Audio connector from DVD to PCI card

*Disconnecting DVD-ROM from IDE cable, and from power as well.

*Muting all inputs and outputs in sound card driver and windows mixer.

*Connecting a CRT monitor on a short cable instead of the projector.

*Making sure everything (PC, monitor, speaker system) is powered by the same outlet.

*Moving GTXPs PCI card to a slot farther from the GF3.


What did help was plugging the speakers into the on-board sound chip. All noise went away.


This suggests to me that something internal and the GTXP are not getting along. I don't really know what else to try to get rid of the noise. Hopefully somebody here has suggestions?


One further possible clue: I get a 60-cycle hum from the Klipsches when the preamp is in standby mode, in all cases. I had thought plugging the amp into the same outlet as the PC would have gotten rid of it, but it did not.


TIA,

Gerald
 

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Discussion Starter · #3 ·
Yes.


I spent a few more hours connecting and disconnecting, moving stuff around, etc. No improvement.


I tested all my outlets with a circuit tester, no problems found.


At some point I am going to install another PCI sound card to see if the noise is coming through that bus somehow.


Gerald
 

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cgmoore,


I suspect it is the analog circuit in the sound card picking up the bus/power supply noise. It is unlikely to be digital errors as those are catastrophic and likely to crash your PC.


A spdif connection should fix the problem. Alternately, you could try a different sound card. Or try replacing power supply capacitors and shielding signal paths if you are adventureous.


-T
 

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One other thing, the way you described what you have it sounds like you cable TV?

Is this to your TV or the ATI card?

Disconnect it and see if the noise goes away.

If it does you probably have a ground loop or a bad connection.

I'm not quite sure how you could get rid of this in this application.

If you are using your analog outs from the sound card to your receiver you can get ground loop isolators. These might help.

Hope you figure this out.
 

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I've got the same problem. The noise started once I moved my hard drives down together into a drive cage down low on my server case. The drives now are closer to the sound card (and the other PCI cards for that matter)which is picking up EMF or other noise off the drives. I know it's the drives because the noise only starts up once I wake a drive up from suspend mode.

When I get some time I'm going to try to shied the drive with foil or something like that. I really think it's EMF and not noise transmitted through the wiring as feedback, because the problem only started once I moved the drives.
 

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The inside of a PC is a very un-friendly place for analog signals with all the "noise" generated by the digital signals. You may get some improvement by shuffling around the cards in your PC or trying a different sound card that may not be so susceptible to the interference. But my recommendation is to go digital SPD/IF out of the PC into an external decoder/receiver.
 

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Discussion Starter · #8 ·
QYV10: I disconnected the CATV, one of the first things, actually. The only thing that makes the noise go away is using the integrated sound chip.


I still have not tried swapping in a different PCI card, or installing the GTXP in another system to see what happens.


HVAC, I have considered trying to shield the PCI card as well, in hopes that it is RF noise. I haven't changed anything internal in some time, until I started trying to troubleshoot this problem. I just wish I had paid closer attention to when it appeared!


I am going to get rid of my RF trackball and keyboard to try and rule them out (in the course of troubleshooting one or the other has always been connected). The last new thing I added was the trackball, but simply disconnecting it makes no difference, so I am probably grasping at straws here...


I am wondering if the PSU is crapping out and causing this. The system has been a bit more "temperamental" lately... but it's Win98Se and been a while since my last slash and burn.


TSingh: yeah, I am definitely thinking of going the digital receiver route at some point. But not for a while yet, unless the problem gets much worse. As it is now, I can mostly drown it out, except when I play games. Then the high pitched sqealing is much louder, from the GF3, I suspect. I swapped in an old TNT card I had and the problem got marginally worse in all aspects.


I was thinking of the entry level Denon receiver, but was wondering how a 70w sub would compare to the Klipsch Promedia's, which is IIRC, 200w.


Thanks for all the replies so far, these forums are great!


Gerald
 

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Discussion Starter · #9 ·
I swapped it into a second PC, same type noises come through there as well. The SBLive value card in the second PC is basically noise free. I didn't put the SB card in the HTPC, since it has a VIA chipset. I am reasonably confident the sole culprit is the GTXP.


So, the GTXP is crapping out. Too bad. This is the second one that I have had. The first one died altogether about a month after it arrived, with mysterious "windows protection errors" on startup. I have seen a couple of those recently... ugh.


I like the features of this card, and when it was performing as new, it sounded really sweet too. I dont think I will buy another one, though.


I guess I will just wait to see how long before it dies.


Thanks for listening,

Gerald
 
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