Power Amplifier To Pair with Klipsch KLF-20's

Hello everyone,
Ever since I picked up my first set of KLF 10's a year ago, I've been hooked on their sound. I now have a set of 20's and wanted to find a solid power amplifier to pair with them. I started using them with a vintage Yamaha CR-2020 receiver that I love, but I wanted to go down the separates route for these. I bought an Adcom GFA 5800 thinking that would be a solid choice, I've been a fan of Nelson's designs and had heard some good things about the 5800. After making sure it wasn't an issue with the specific 5800 I have, it seems that I'm feeding these KLF's a bit more than they need. There is quite a bit of background noise almost sounding like there is a loose connection between some of my equipment. I assumed that the power was the issue since the KLF's are very efficient loudspeakers and my 2020 which puts out 105 watts per channel didn't have any of this background noise. I was using the KLF 20's and the 5800 with a Threshold FET 9 Preamp and an Oppo BDP-95. To test my assumption, I had a friend bring over a pair of Source Technologies 7211's which are much less efficient in comparison to the KLF's and hooked them up to the same equipment. Sure enough the background noise I was hearing with the KLF's was gone. At this point I think I just need to get a power amp that is putting out something much less than the 250 watts this Adcom puts out. I'd ideally like to spend somewhere in the neighborhood of 600 dollars. I don't mind buying used. Any other KLF owners here with their recommendations?