The 6SN7GT is a small glass tubular audio double triode. This was a classic design with two separate triodes in the one envelope. The 6SN7 remains the most popular Octal based double triode valve for audio applications. The valve is especially well suited to phase splitter designs.
The etched Type designation on the glass matched the American pattern but the base clearly states Made in England.
The twin triode sections. For audio use an internal electrostatic screen is not required.
Here the cylindrical cathode tubes can be seen complete with insulated heater wire. The control grid winding extends below the anode.
The wide glass tube envelope is 29 mm in diameter and, excluding the IO base pins, is 64 mm tall.
References: Data-sheet, 3002 & 1040. Type 6SN7GT was first introduced in 1941. See also1941 adverts.