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....
=================================
Considering that with so many valves (tubes) in parallel operation the
inter-electrode capacitance is multipled accordingly, it would be intriguing
to know up to which frequency this set-up could be sensibly used.

I have quite a number of 'never used' 807s in the junkbox , pardon me
.........NOS box.

Frank GM0CSZ / KN6WH