OK so here are the matched pairs i am trying in my system:
Raytheon 6SN7W
RCA red base 5692
So far I have had the Raytheon and RCA in the preamp. I'll spend a bit more time with them and the others before i give detailed comments. However I will say that the RCA is a very nice tube that I have read mixed reviews about.
Heard these at Jim's on Monday. Here's my impression:
Raytheon 6SN7W - nice balance, with good dynamics and a decent tone. Tight bass and good highs with plenty of detail on leading edge transients without fatigue or zing
RCA red base 5692 - beautiful mids especially on vocals and horns, somewhat slower sounding than the Raytheon with a fuller but less tight bass, top was somewhat reticent