304TL based Class A

[cloudbuster]

OK, great.
I never knew this, but these tubes have tantalum plates. The plates act as the "getter" by absorbing gas, but they have to be glowing cherry red in order for them to do this properly. That's why these tubes have no silver spot inside the glass envelope; the red hot plates absorb the gas.

Found this old post. Fascinating! In nearly all cases, you heat objects in a vacuum to get adsorbed gasses off of them. This looks like the reverse. The only likely possibility is that the gasses are not being adsorbed, but the plate is reacting with the gasses to form non volatile compounds. Tantalum oxide, nitride, etc. Glad I found this. I have some 304s I was planning on working with. Now I know how to start.

 

[Superhik]

304TL Circuit

How did it turn out? What did you use for output transformer?