Tube preamp recommendations for Pass X260.8 monos

Congradulations.

I have owned Pass amps for nearly 40 years. By far the best preamp matches have been Audio Research… preferably Reference level. I also always paired with a Audio Research phono stage (and now DAC as well). I owned Pass preamps for part of the time… much preferring ARC. Just as detailed, only more musical and with better fleshed out midrange and upper bass. 
 

Other options: Conrad Johnson and VAC. But obviously voting with my money has been for ARC. You can see my systems under my ID.

I was almost certain Audio Research was going to be the first, and most frequently mentioned preamp; it’s almost impossible to not love that gear. I’m guessing that Nagra, Conrad Johnson, Luxman, Cary, Musical Fidelity, and Rogue will all have their proponents. Both the Audio Research Reference 6SE, and the Nagra Classic seem an attractive pairing, but my goodness that’s a lot of dough for a pre.

Cary SLP-05.  Run it in balanced mode

Are you looking for a more neutral-sounding preamp or one that provides a bit of warmth, bloom, tube magic, etc.?

Backert Rhythm 1.3.

Or Rogue RP-9.