I researched the PS Audio Power Plant and didn't like the efficiency factor much, as Sugarbrie suggests. At the end, I purchased the ExactPower 2000 which seems to do the same kind of job with a lot less waste. It made a world of difference -- vocals came across much cleaner. Check out the website. It provides a clean 120v (so is also a "surge protector") and acts as a line conditioner if I'm interpreting things right. A little pricey, though you might be able to get some good deals in the classifieds.
