Best 6NS7 Preamp for a Pass Labs XA25 amp

Will need a remote.
There must be a couple happy XA25 Amp owners out there?
@coachpoconnor   can you elaborate a bit on your Supratek as in upgrades ,  what it cost you,   how many inputs ,  how long have you had it and by chance if it needed service would your only option be to send to AU?  Have a remote and if not any info about the remote and if more functions are available for the remote?     I could simply email the builder I suppose although at this point in time would like to hear of others experience with Supratek. 

+1 on the Atma-sphere.  Surprised it hasn’t been mentioned yet.  I’m slumming it with an MP3 (kidding) but had tried the MP1 and was outstanding.  That’s what sold me instantly and went on a search for a MP3.  
Works great with my XA monos

You can't go wrong with a Supratek preamp. I have a Supratek Sauvignon (highly modded) mated with a FW SIT-3 amp and the pairing is wonderful!
The Supratek is the only component that I have not changed over the years. It's a keeper!
Aric Audio is great stuff, also Linear Tube Audio Preamp, MZ3 or even the MZ2 would be great.
Dehavilland Ultraverve, I used one for a few years. Excellent open, airy sounding preamplifier.