Lamm or Allnic Preamp

First of all, I havn't audition the Allnic L-6500 line amp. However, I built my own 5845 single stage line amp with Monolith line output transformer. The result is really good with superb clarity and musical.

The L-6500 is with similar design that I believe it would be a good match with the Air Tight 300B.

The new Spatial Audio Raven looks most interesting and they offer a trial period.  Same for Aric Audio Motherload XL.  Sorry, I know they’re not the models you asked about but thought you might at least might be interested in taking a look as feedback has been outstanding and may save you $$$.  Best of luck. 

I own the Spatial Audio Lab Raven. It is the brainchild of Don Sachs and Lynn Olson; two very talented and highly respected audio designers.  It is outstanding and my end game preamp for sure. All those mentioned above are widely praised by those who own them.  You might add Atma-Sphere to the list.  Good luck with your pursuit.