For what it's worth, I agree completely with Peter. RCA 5692 is the best I've tried with Sylvania 6SN7 GT a semi close second choice.
RCA is more dense, sightly better dynamics and beautiful “flat" top end. Sylvania will be ever so slightly more extension which may or may not be desirable depending on tonal balance of entire system.
RCA is more dense, sightly better dynamics and beautiful “flat" top end. Sylvania will be ever so slightly more extension which may or may not be desirable depending on tonal balance of entire system.