Sensibly equivalent¶ to:
The 805 is an HF transmitting triode rated for use up to 30 MHz.
The operating conditions are for Class C service. The control grid current is up to 40 mA.
The anode is milled (expensively) from a graphite block. One advantage is that this can be baked at a very high temperature during manufacture in order to expel contaminants and occluded gases. We believe it to be a direct ancestor of the 813 (also TT10).
The short stub pins may have been designed to fit into a bayonet fitting with spring clips to make contact with the pins.
The wide glass tube envelope is 55 mm in diameter and excluding base pins it is 194 mm tall.
References: Datasheet & 4061. Type 805 was first introduced in 1936.
Absolute Maximum Operating Conditions¶
Updated February 14, 2013. shape:wide.glass.tube construction:pinch type:triode age:1930.1940 base: pins:4 pin:1.f pin:2.ic pin:3.3 pin:4.g1 pin:tc.a