Bflowers, Tboooe, is for sure correct. I had the very same same problems with my Pass 350.5s when plugged into the Running Springs Dukes power conditioners.
I have now moved the Dukes to feed my front end components, 1 pcs just for my BAT 51SE pre and the other for my CD Player. The effect that I like about the Dukes in the front end is that the lower bass notes have gained clarity and volume.
My amps work much better with the upgraded PC only and without the Dukes.