Inspired by This Thread
I decided to build something similar,I've though about it before,and had some parts sitting here,so what the heck!
Here's what I've got at the moment.
25BQ6GTB tubes,(re-)branded DuMont. These are the skinny 6V6-sized bottles.(11W anode rating,and ~200V screen rating)
A pair of those are driving a 3.5K PP output transformer,rated for ~100W. (came from a scrapped Bogen M120 4x PPP 8417 amp.)
Vk (33ohm Rk's) ~1.3V ,About 40ma/tube.
(I saw cathode current peaks of ~80ma per tube,perhaps more? hard to tell with my DMM)
That gives a dissipation of ~18W per tube. Much more current and the plates start to 'blush'.
I did *not* see any screen glow,but the mica's on these particular tubes make it kind of hard to see much inside....