Lamm L2 Reference tube recommendation

The thing is there is swapping signal tubes and swapping power supply tubes. The LL2 is a tubed pre with a tubed signal path. The L1 and L2 are solid state with tubed power supplies. So in a well designed circuit, there is less of a difference with swapping tubes in the ps.
But in my case with the L1, the difference was easy to identify albeit small.

I dont think you'll find much improvement tube rolling with the L2. The most important thing is to check the voltage output of the power supply as specified in the manual. Slight deviations, usually loss in power will make it sound dark and veiled. Unfortunately I found myself making this adjustment weekly and replacing the tube monthly making it too high maintenance for my taste.

Between the RCA and Raytheon, I prefer the Raytheon. It is just slightly more natural in its presentation. The difference is small.

well, I finally got the L2 yesterday. DHL lost the PS crate but were finally able to locate it ;) The pre came with Dumont 12BE3's, a RCA 5651 and a Sylvania 12ax6wa. Once I get my Innersound xover repaired I'll be able to check it out ;)