[Savy]

I have a 6l6 fender combo with a GT12ax7-m in holes 1 and 3 (hole 2 is
a 12at7 reverb driver)
and a 12ax7 LTP phase inverter.

I had just bought a couple of 12au7 to try to quell tube hum (which it
did when used as a driver in hole 3) but of course doesn't really
supply the PI with enough gain. I opted tp try it in the PI instead and
Well... quite good results in tonal variation and timber can be found
by using either a u7 (mid gain) a t7 (mid-hi gain)or an x7 as a PI.

The u7 was interesting because it seemed to allow for more preamp type
subtle overdrive into the fairly clean output pair of 6L6 s. (think of
the guitar sound of the Georga Stalites or George Thoroughgood ... or
crisp tele bridge position PU driving a small amp into clipping)

Switching to a 12at7 in the PI hole rounded out that sound and felt a
lot more lively having a thicker bottom end.

and so finally sticking in a 12ax7 brought the amp back to it's fullest
potential with more robust tone and fuller low-mids with more vocal
like tonalities.

Might be Cool to be able to "Live switch" between lets say the 12au7
and the 12ax7 for possition as the PI.

Anybody hot switch with success.

I know there is one of you out there who has been able to live switch
pentode to triode but wants to be paid for sharing.

Sorry... I'm broke ! but will share my good fortunes with others.

Any wheels turning out there ?

thanks, Savy