Unless you have a REALLY high end sine wave UPS (Uninterruptable Power Supply), get rid of it for all your audio gear, it doesn't have the balls to save you anyway. UPSs by thier nature inject all kinds of horrible hash onto the mains power. I mean get rid of ALL of them on the same phase as your audio gear. Don't even have'em plugged in in the same house if possible.
Repeat after me, as often as it takes,
One path to ground. > One path to ground. > One path to ground. > One path to ground. > One path to ground.
“Mike Taht: One path to ground!! [1]”
Of the people that read me, Smirk and Wlofie may find this interesting. Mike Taht has a whole (Battling Hum …) [2] bunch (Digital Hash) [3] of posts (blinkenlights on the hash bash) [4] about power and audio systems.
[3] http://the-edge.blogspot.com/2005/08/digital-
[4] http://the-edge.blogspot.com/2005/08/blinkenlights-on-hash-