Its all perspective, and it drives me crazy sometimes, I have RCA cleartops , bought them from rogue, the test well but are bright and edgy in my system. I dont like them at all.I've been wondering if a factor that might contribute to the variability of different people's assessments of dual triodes (aside from the obvious variables of systems, rooms, music, listening biases, etc.) is the degree to which the two sections of particular tubes may have differing characteristics, and variations in the degree to which different circuit designs may be sensitive to that.
As I mentioned above, in the case of the absolutely NOS 1957 RCA 5963's that I had been using, while the different tubes were well matched to each other, there were significant mismatches in transconductance between sections. Different circuit applications, obviously, will have differing sensitivities to that.
As you saw, Chris, I had raised that question in this thread, in a post dated 8-25-2010. Kirkus provided an excellent technical response, but there was little empirical feedback.
Best regards,
-- Al