Tube amp recommendations to drive Paradigm Tributes


I am looking for recommendations for a decent reasonably priced Class A / Tube amplifier for my listening room. I currently have an integrated Peachtree Nova500 driving a pair of Paradigm 30th Anniversary Tributes.  The Nova supposedly outputs 500 watts per channel (into 8 ohms). The Tributes specs say impedance is  "compatible with 8ohms" I'm not exactly sure what that means. Regardless, the system sounds very good and I enjoy it. However I am very curious about class A/tube amps. Last year I listened to a Bob Carver Crimson 275 amp and was very impressed. I wonder if that would be a good match for the Tributes. Any input would be appreciated.
ronwave
Are you wanting an integrated amp or an amp + preamp?  What is your budget?

I'm planning on using my Nova 500 as the preamp, unless I find a better integrated solution. Budget is wide open at this point.
@ronwave 

Regardless, the system sounds very good and I enjoy it. However I am very curious about class A/tube amps.

You will drastically change the sound you say you enjoy so much by going from Class D SS to Class A tube.  I'd be surprised if using the Nova500 would provide a magical pairing when using it only as a preamp to the tubes.  I'd definitely buy your tube amp used so you can sell close to break even if you decide the synergy isn't great.  You're just tinkering to see what other sonic signatures are all about and there is nothing wrong with that but it doesn't sound like you're being very deliberate to try to see what tube magic is all about by cobbling together new and existing components that are just handy for you.