Looking For Neutral Tube Amp Recommendation

If your pre puts out a balanced signal, a pair of Atma-sphere MA-1 or MA-2 monoblocks might be a good choice. They are not romantic; I would call them fast, transparent, dynamic and relatively neutral. They do not sound like solid state, that's for sure, but not colored, either.

The Lamms are always at the Rocky Mountain Audio Fest. Go have a listen. Beware though. The 3.0's are out, and they are definitely out of your budget!

Your description and speaker screams a great match for Atma-Sphere. The current mk III versions are best. The MA1 mkIII would be more than powerful enough for your speakers, and perhaps even the M60s would be a good match and save you money/energy/heat. Mate w/balanced preamp to get the most out of the design.
My Dehavilland Aries 845G would also be a good fit. They are SET, but more powerful than most SET, and mate well w/wide range of speakers. A tad sweeter mids than the Atmas, but still not euphonic like many tube amps. The newer model with the GM70 tube is even higher power if you don't mind a less common tube.
The Lamms are also a good choice.
Cheers,
Spencer

Until I hear better, I'll keep suggesting the Dodd mono blocks with all the upgrades. My room is about half your size but with about the same imp & eff speakers. My musical tastes are quite similar to your own too.

I doubt if i ever tax these amps. they sound great with even complicated musical passages, are dynamic and definitely involving. Easy to maintain, and inexpensive to roll tubes in or re-supply tubes too. Are a slam dunk budget wise used, and a quarter of the budget new. the newer ones reportedly have still more headroom. They are single ended only however, no XLRs. Very nice however.

Albert P could shed more light I suspect, on the Dodds.

Good luck

I think the answer to you question is the VAC 300.1 extremely
musical but very great low level detail.