On 5/12/19 6:04 AM, Cursitor Doom wrote:
My question is, does a valve like a 12AT7 require
different DC biasing points for every range of frequencies? Obviously the
range switch is switching in different combinations of coils and
capacitors, but is it likely to be also switching in different cathode-
grid DC biasing at the same time?

A make and model would help considerably.
But, I'm gonna generalize here, if it's cheap enough to only
have two tubes, they certainly didn't waste any money on
complications like switchable bias.

--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com