Try out an Equitech balanced power unit. You'll be pleasantly surprised. Experiment with the pre as well or independently.
I've used Panamax conditioners around the $200 price range in the past and they made an appreciable difference while I was using outlets that were wired into the regular house electrical circuits.
Then I installed a dedicated line from the breaker panel that utilized quality outlets and I found the power conditioners were no longer required.
But that's just in my house - some people live in areas that suffer from excessive line noise that required conditioning, but I appear to live in a fairly quite area.