New tube preamp

I have only limited experience with the specific pieces of gear you have in your system: the Kubala cables, just barely left of dead neutral and superbly transparent. The Pass xa30.8 is an exceptional amp. Before you dump the PS Audio preamp, which Ive admittedly never seen or heard, you may wish to try some different tubes. Ive listened to alot of 12au7’s through the years and the Telefunkens are not among my favorites for tone or texture. Could I suggest you drop in some NOS Cifte’s/Mazda’s for a more illuminating presentation or NOS Mullard’s/Brimar’s for a more fullsome, tonally saturated presentation.

No offense intended but you have such a variety of gear there that I would venture to guess that no one can assist you more than to blind guess along with you. I must admit though that Ive never heard of anyone....you are the first....who drives a Pass Labs XA amp with a PS Audio preamp. I use Audio Research in my main system and when I had a Pass Labs XA amp I drove it with a Ref5se and it was a terrific combo.

Good luck.

Several have recommended de Havilland as I listen to my Mercury 3 from Kara.  Terrific stuff!  Her preamp replaced my Manley Neo-Classic 300B with Taketsuki tubes, no slouch.  I recently reviewed it here, gave my impressions of the preamp and listed my system.

Given your stated priorities I’d reiterate my prior recommendation for the Don Sachs Custom Linestage. At $2500 with all options and a 14-day trial period it’s an attractive package. Someone who responded to another thread had a friend with both the Sachs and MicroZOTL preamps, and although both were excellent the Sachs had a little more tonally rich, which would seem to lean more to your tastes.  FWIW and best of luck.

Any updates on your journey for a new Preamp? 

One more thing. Have you tried running your system without a pre (maybe thru your DAC, etc) and see what kind of sound you are getting? I'm just not certain switching Pre amps at the price level of BHK will provide jaw dropping differences. You already tried tube rolling. One other thing, is 30 (4 ohm) solid state watts enough for your 83 db speakers?