"coffelt2" wrote in message
...
This does not answer the question, but is offered as a bit of
homebrew lore.
After WWII, the 1625's were plentiful and cheap. Some Ham found that
with
certain brands of 1625's, the suppressor grid was not tied to the
cathode
inside the glass envelope. The two were tied together inside the tube
base.
So, after removing the base, the two elements could be separated from
each
other.
The aim was, guess what? Suppressor-grid modulation! I can remember
hearing some of these rigs on the air. I don't know just what
percentage of
modulation was possible, but I remember it being pretty weak. Good
strong
signal with very low modulation level.
The aim had been to use what parts one had, and it surely was an
inexpensive
way to join the AM crowd!

Old Chief Lynn, W7LTQ

In the 1957 ARRL Handbook, these particular tubes were also used in a
cathode driven (grounded grid) amplifier.

73, Barry WA4VZQ