Tube recommendation for Audio Research LS-2b?

I had an LS 2b. Have a LS 5b as a backup pre

You really need warm tubes for the LS2

nos telefunkens,mullards and amperex from the sixties worked like a charm for me

I own also a ls22 and i measured that my EI ecc88 have a fillament
current togheter of 1.6A[incl.relay circuit].that is already to high for 1.5A max.LM317!For example a 7308 have more current than that.

I had the LS2 a number of years ago, and it definitely needed the warmth and slightly softened highs provided by Amperex Bugle Boys. The BB tubes were also very dynamic. In contrast the tubes I bought from ARC, a Chinese 6DJ8 and a Sovtek 6922, were coarse, grainy and lacking in refinement.

I have an LS2B-MKII and have compared the stock Sovtek 6922 with an Amperex 7803 (PQ/Orange). The Amperex was much more detailed but added a slight sibilance. I'm not sure if the tube was the issue or whether the preamp needed a bias adjustment. (the seller said the tube was NOS and tested well).

The 7308 is the top of the line tube in that category. The Amperex is an excellent tube. Very low noise. Provided it is a legit Amperex. It should have a number etched in the tube I believe.