KT77 vs 6L6

Deijavoo

I'm considering changing my toobs from 6l6 to KT77, dead easy to do on my amp, I just wondered if anyone else have done this before and ask for their thoughts on the differences/preferences in tone change? 

digitalscream

I went from 6L6 to KT66 on my JCA50H, and it resulted in a generally much better sound - sort of more of everything. More depth, more defined mids, smoother highs.

Of course, as @ICBM pointed out at the time, that could just have been a function of the fact that the Golden Lion KT66s were of better quality than the 6L6 valves I had in there previously.

In other words...it might be good, it might not make a difference

ICBM

Do you mean 6L6 to KT66? 6L6 and KT77 are not usually interchangable unless the amp has a 6L6/EL34 switch - they need a fairly big adjustment in bias voltage. (Although unlike EL34s they shouldn't need pin 1 connected.)

KT77s sound like beefier EL34s. There's still not a huge difference even between 6L6s and them though, it's just a slight shift in emphasis rather than a complete change in the sound.

Deijavoo

Yeah I have got an external bias control on my amp and is apparently a cinch to do. I'll maybe do an a/b test.