I have a tube integrated amp it uses (4) 6V6's for output tubes and (2) 6SL7's for input/driver tubes. The amp is manually biased by (4) pots, one for each output tube.
My question is, when I change input/driver tubes do the output tubes bias change significantly? Should I re-bias the output tubes every time I change input tubes or will the input/driver tubes not affect the bias of the output tubes that much?
I rolled in a NOS pair of 1948 Tung-Sol JAN-CTL-6SU7GTY pair in tonight to make sure they work since I just bought them. The prior tubes were RCA 5691 "red base" and the bias really didn't change at all. Is this typical or did I just get lucky? It's a slight PITA to bias this amp and if I can avoid the hassle when I roll the RCA's back in that's fine by me.
Looking for first hand-knowledge and opinions. It seems to me in a SS amp changing the input/driver tranny's would affect the output tranny's, but maybe for a tube design that's not true.
I will say there is a night and day difference in sound between the RCA red base 5671 and the TS 6SU7GTY.