Digital Source Conditioning??

Check out the Blur Circle power line conditioners that come in the PVC tubing. What you save on looks will be more than made up in the sound.

All the best,
Nonoise

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.

Your amp and pre sound happy to you only because you haven't heard the transformation good isolation/conditioning can make.
If you're happy leave them alone; just deal with the digital.