The Helikon A216 is an output triode from 1927. It was made in Austria and little else is known about it.
The main structures are obscured by the gettering. The base pins are of the simple split-pin type.
Looking up from the base reveals a horizontal cylindrical anode, helical grid and single strand filament.
Here the construction can be seen to follow the early R Type design for anode support. The filament is held in folds of the supports suggesting thoriated tungsten.
The balloon envelope is 45 mm in diameter and, excluding the B4 base pins, is 85 mm tall.
Reference: Data. Type A216 was first introduced in 1927. See also1927 adverts.
