What tube pre-amps pair well with Pass amps?

KR is a Czech company which helps keep the prices down a bit compared to Germany. They are best knows as a premium manufacturer of tubes and their Kronzilla power amps.  

I sell a lot of their tubes.  Quality is extremely high though as odd as it sounds, the KR amp does really well with EML 45s.  KR tubes are best when the current can be increased when biased which doesn't happen in a preamp.  

PM me if you want to discuss pricing.  

Currently using a ARC Ref 5se with Pass 260.8's, to me a very good combination

VAC for best sound.

You've got a smattering of responses and I'll add mine. When looking for a pre to pair with my first watt f4, I read a lot about tubes and topologies and eventually settled on 6sn7 based units. If you want a balanced design, I'd look at atma-sphere's offerings. For single ended, I was choosing between de Havilland, Don Sachs, and supratek. I eventually ended up with the Don Sachs and it improved everything about my system performance. Didn't get to demo the competition, but from the reviews, I don't think you can go wrong with any of those choices. The 6sn7 is nicely linear and sweet. I'll probably still try out a supratek at some point...

I heard the pass xa25 with Backert tube pream it’s a superb combo , all the accolades you mentioned were all there and some...