The 1Q5GT is a battery audio output valve capable of providing around one quarter of a Watt of output. It was designed for use with a single dry call as filament supply and 90 Volts HT.
The bright oval anode. On the left is the support for the filament tension spring.
The anode seen face on.
Looking through the top mica. The two inner grids look to have the same pitch. The beam plates at either end are flared slightly and cover the supports for the grids.
The wide glass tube envelope is 29 mm in diameter, and excluding the IO base pins is 60 mm tall.
Reference: Data-sheet. Type 1Q5GT was first introduced in 1940. See also1940 adverts.
