I've been trying to pinpoint where the noises are coming from. I run all my gear through a Furman that is hooked through a UPS (to be extra anal) and the buzzes and hums got a little better but I still get sizzling. Not crackling, but sizzling. Will hooking up something like a hum eliminator do the trick? I know it isn't a hum but could it be related? Gear is: Computer - Mac Pro Soundcard(via Optical) - Edirol FA-66 Sub (from FA-66 via Balanced XLR) - KRK RP-10S L/R Monitors(from Sub via Balanced 1/4") - KRK Rokit 5 I've tried hooking up the soundcard to the MacPro via Firewire but that just gives me all kinds of demonic noises. Optical has been the way to go for me. Anyone know how to solve this?