@mordy and @richdytch Inspired by your posts I've played around too- given the awful stormy weather tonight this seemed a sensible thing to do. Using EL3N drivers I changed my RCA 6BL7s' accompanying power tubes between the modern Russian re-issue T-S 6SN7GTB, and the original T-S 6SN7GTB and a T-S 6SN7GT, both from the 50/60's. The two TB's were very similar and as you describe, rather woolly and lacking clarity, but the GT was much better and lacked nothing in neutrality, clarity and imaging. Actually very good sounding. However, when I switched drivers to the K-R VT231 the sound firmed up all round with all three tubes and sounded very good, but again the 6BL7/ T-S 6SN7GT combo was my favourite. Excellent, rich, clear sound. As you say, so many tubes combos sound good with Elise- we have so many options.