spamhog wrote:
On Jan 17, 12:48=A0pm, Chuck Harris
No, but don't let that stop you from trying it anyway.

-Chuck

:-) What keeps me is the fact that I have no idea how I could measure
the core temperature in a tube!

With an infrared thermometer or optical pyrometer. Auto parts stores
should have a model in the $20 range.

Is heater current temperature-dependent enough as to provide a proxy?

No, because the plate temperature is very different than the cathode
temperature, and the plate temperature is what you worry about.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."