I think I have found the End Game Amp

Probably not fully broken in, 60 hours so far, but I spent yesterday pm playing with tubes.  My preamp is the Cary SLP-98 so that features in the quest.

What sounds best (so far) is:

For fun I fed this combination to Google AI and got approval (others did not).  In particular it recommended NOT to use NOS tubes in the Buffer positions of the SLP 98 as they are driven quite hard and could die prematurely - also make the sound too syrupy (agreed).  When I state that I listen at fairly low volume the AI response is (just) approving of the total system - even my Atria II speakers. Tongue in cheek here, but the AI summaries did give useful hints.

The JAN Smoked Glass tubes (how I had a pair I do not know - they are about as common as hen's teeth - but I have found a pair for spares) these do magic in the mid range.

The TungSols are meaty - both in sound and construction and so can handle the demands as buffers.

The 6SQ7, transparent and musical

The LinLais, airy, extended.  These made the sense of space much more real than NOS tubes.  I cannot try these in any SLP-98 position as the bases are too big.

RCA 2A3s, seem liquid and natural, I do not have a quad of any other variety.

The resulting sound, within volume limits, is as good as I have heard.  I did play Rattle's Mahler 3 (CBSO)  with 92dB peaks which is loud enough for me! The Sveshnikov Rachmaninov Vespers' a cappella voices are sublime.  In every work, in good recordings, pianos, strings, brass and woodwinds just sound real.

Bad recordings stay bad.

I haven’t been around those speakers nor the amps but I’ll reiterate another poster’s sentiments….2A3 not the best pair up with those inefficient Rockports

 The 6SN7's will find a very special synergy if worked with Power Amp Input Tubes, as the investigation.

Not cheap, but 1950's RCA 12BH7A Long Black Plate Valves receiving a signal from a 6SN7 Line Stage could become substantially more than the sum of the parts.

The idea of all four 6SN7's not having to be a matched quad helps, as 2 x matched pairs is an option as well. 

Whatever the permutation, I have about $600 as the price if Vintage Valves are the selected models. How does proving Valve purchases made are measuring near factory spec after receiving any purchased Input Valves get managed??     

@lumakuu They are PP, so 4 x the Power.  They will drive the Atrias to much louder than I can listen.  My average level is about 70dB.  Peaks at perhaps 90.

The SE 2A3 Elekit was almost enough.

@lumakuu @posbwp55 Much of my listening is chamber music and choral works where "bass slam" and other artifacts requiring power are not relevant.  The usual max spl of those genres is 90dB or less and the 14 watts are fully capable of doing that.

Even listening to the opening of the last movement of Mahler 7, timpani going wild, is rendered cleanly and satisfactorily, though at less than real life volume.

The Atria IIs have a sonic character that no high efficiency speaker can match - thin paper cones, horns etc. color the sound.  I will trade off the slam and volume for the sheer beauty, delicacy and elegance that the Triode Lab PP 2A3 and Atria ii speakers yield.

I have tried a variety of pre amp & power amp combinations over the last two years and the current setup, though perhaps unconventional, is yielding the best sound, based on my desired qualities and music preferences.  I realize that the setup is "at the margin", SE 2A3s and 300Bs did not quite handle orchestral works.  Solid State was not beautiful, powerful PP tubes (KT 120s) sounded good (indeed the C-J amp was very good) but did not quite have the magic of superbly executed PP 2A3; yes, Mahler's timpani had more slam but the beauty of the human voice, and the sense of space, in liturgical works, was not quite there.

I appreciate your comments but I think my listening preferences may be somewhat unusual.