Years ago I did quite a bit of tube rolling with an LS2B, along with a friend who also owned one. The warmest of the tubes we tried, if I recall correctly, was a Mullard, while the German variants (Siemens and Tele's) ran very linear and more on the neutral side. Hope that helps. Also, my LS2B had been modded by GNSC - in direct comparison both of us could tell the differences blind and that mod occurred to both of us as worth the price at the time. I don't know what they're charging now. Improvements were not in warmth though, but more in resolution and soundstaging.
