This month we have another rather unusual tube. The 3C24:
The 3C24 is a transmitting tube developed for Class B audio amplifier or modulator use or for Class C RF amplifier or oscillator service.EIMAC data sheet. The tubes shown below are kindly provided by Josef from Vienna who has a good collection of some crazy tubes.
Starting with a 3C24 in military packaging made by North American Philips Co. (Norelco).
The tube also has the military type number VT204 printed on the base.
A 3C24 made by Lewis Electronics:
Another Lewis 3C24 in different packaging:
The next one is from a rather unusual brand.
I never came across this brand name before.
The tube bears the HK (Heinz Kaufmann) logo which to my knowledge was a rebrander.
And lastly an EIMAC 3C24:
Due to the structure of the tube with the plate enclosed on the top, only some glow at the bottom is visible when the tube is in operation:
A shot from below where the unique filament and grid structures are visible. The filament is a spiral around a central rod with the grid as cylindrical cage around it.
I hope you enjoyed the tube of the month presentation. Thanks to Josef for lending the tubes to me.