The 1T5GT is a battery audio output beam tetrode.
In single ended output service the anode load would be 14,000 Ohms. The audio output is low, but respectable for a valve operating from dry cells and having a low filament current.
We also have the 1B8GT that combines the 1T5GT and 1H5GT into a single envelope.
The wide glass tube envelope is 28 mm in diameter and, excluding the IO base pins, is 59 mm tall.
References: Datasheet & 1043. Type 1T5GT was first introduced in 1939.
Absolute Maximum Operating Conditions¶
Updated July 26, 2017. shape:wide.glass.tube construction:pinch type:beam.tetrode age:1930.1940 base:io heater:1.4v pins:8 pin:1.- pin:2.f+ pin:3.a pin:4.g2 pin:5.g1 pin:6.- pin:7.f- pin:8.-