Some of these are valid possibilities I guess. Yes, my Empeg is at 0db. But I'm not actually going from my Empeg into my sound card. Here's my setup for some clarification:

Kenwood stereo receiver (most gain comes from here)
    + BST 4 channel mixer (a tiny bit of gain and equalization)
        ch1 Empeg (0db, no gain)
        ch2 SBLive sound card
        ch3 CD changer
        ch4 VCR

So, the 4 sound sources go into the mixer, are equalized and given a tiny bit of gain, and then go into the receiver. My CD changer and VCR inputs have no hum at all, even when I turn their gain up very high. This rules out any issues with the mixer or amplifier creating the noise. All cables have been switched and checked, and I've tried using the same devices on different mixer inputs. So the hum happens with the sound card, or with the Empeg when the USB/serial cables are connected. All computer stuff is into grounded (3 prong) outlets. Also, the Empeg is on the same power supply as the amplifier, but a different one from the computer. (Well, different surge protector, from the same outlet actually, but I can't really reach any other outlets.) USB and serial cables aren't wrapped up in any other wires.

I think the above info rules out all except #2. I can't really get the Empeg to another outlet without a long extension, but I really don't think power supplies are the most likely candidate, are they? I think the fact that the hum happens *only* wheh the USB or serial cables are connected means something is coming from my PC, right?



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MkII 080000554