Sensibly equivalent¶ to:
The DET25 transmitting triode has a large square four pin base as can be seen from the picture it is directly equivalent to CV1025. The anode box is quite large and blackened to radiate heat more effectively.
Operating frequency would be in the HF range and probably the output power was of the order of 36 Watts.
The electrode assembly can be seen in this picture. The filament is made of tape and is formed into a double inverted V. The tensioning springs can be seen to the right hand side.
Also in this picture the etched type description is typically of M-OV pattern and thus we can be sure of the manufacturer.
The wide glass tube envelope is 51 mm in diameter and, excluding the L4 base pins, is 150 mm tall.
Reference: Data-sheet & 1005.
Absolute Maximum Operating Conditions¶
Updated October 18, 2014. shape:wide.glass.tube construction:pinch type:triode age:1930.1940 base:l4 pins:4 pin:1.a pin:2.f pin:3.f pin:4.g1