Today I have another rather uncommon tube to present: The 12E1 beam tetrode.
This beam tetrode was designed as regulator tube in power supplies, either for series or shunt regulation.6CB5A. It offers a higher plate dissipation rating as the 6CB5A and needs less heater current (1.6A vs. 2.5A). These beam tetrodes usually are quite tough and can be driven at their maximum ratings. But I admit I never looked in detail how well it would work. Check the data sheet for a complete set of technical specs. The plate curves don't look too shabby. Here the triode connected curves from the data sheet:
And the curves from an actual tube sample from my stash:
Since I never used this tube in a project I did not accumulate many of them. These 4 are all I have:
Let's have a closer look.
My 12E1s are made in England by ITT.
The base is made of micanol: