I have a new Jolida 1701A Hybrid amp(50W per channel solid state amp, with two 12ax7 tubes in the preamp section) It is excellent, and I'm looking forward to some tube rolling to see the differences.
With these tubes(12ax7, 5751, Etc.) how picky do I have to be with matching & balancing?? I am looking at a pair of 5751 triple mica RCA blackplates with tests of 40/40 and 42/44 with 32=min. good, and 50 as new. Just a matter of one wearing out sooner, or a sonic difference? Which is more important, the inner tube specs, or one tube to the other? and what tolerance(2%, 5%, 10%) is tolerable!
I assume that even NOS same date pairs should be tested for match & balance, they are pricey. Hope I didn't ask a book sized question, tried search & got nowhere. Thanks!!!