Lamm L2 Reference tube recommendation

I have the L1 and the power supply has a similar tube complement, 12AX7, 6C19, 5651, but not 12AX3.
I have found that there can be small changes with different 5651's. See what you can find and give it a try.

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.

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