That's similar to my ideas, which include doubling the 240V mains to 600V to
put on the plates. an isolation xfmr would be needed for the filaments, tho.

600V at 4-5A would give a ballpark of 50 ohms plate resistance, low enough
for no-tune techniques.

Still haven't found that tube # tho ;o)

73, Dave, N3HE

SNIP
After reading an article about building an amplifier which used ten 1625's
with paralleled RF but with series filaments directly across the 120-volt
line, I've been saving them; hope to find the right round tuit someday....
SNIP