Sensibly equivalent¶ to:
The APP4G is an audio output pentode with a 9 Watt anode dissipation.
The old Army service code is ARP10 that became the CV1329.
This close-up image clearly shows the three wire grids of a pentode with a copper support for the control grid, it also shows a round oxide coated cathode with an insulated heater passing four times through the cathode tube.
Thanks to Mark Mallison for sending these images.
The classic envelope is 36 mm in diameter, and excluding the B7 base pins is 100 mm tall.
Reference: Data-sheet. Type APP4G was first introduced in 1939. See also 1939 adverts.
Absolute Maximum Operating Conditions¶
Updated January 09, 2022.