Joined the club, Rod pentode superhet radio.

[AdrianPH]

Rod valves or Rod Pentodes are literally using metal rods rather than the conventional wire grids/screens information can be found here :-
https://www.radiomuseum.org/forum/summar...todes.html

supposedly very robust when it comes to being fired out of big guns when used as proximity fuses etc. But probably not designed for very long life.

I also have a few ECC70/6021 5840 valves that I have used for projects in the passed, these are typical 6.3 Volt heater valves ,Twin triode and Pentode respectively both with conventional grids.

The gm on rod valves seems to be quite low when compared to normal grid valves, but are fun to play with. Will have to get some smaller hearing aid type valves and play with them soon.

Thanks for the comment.

Adrian