The 12Q7GT double diode triode was designed for receiver audio use.

The diodes would be for signal and AGC rectification and the triode would act as AGC amplifier or first audio amplifier.

The wide glass tube envelope is 28 mm in diameter and, excluding the IO base pins, is 70 mm tall.

 
Pin Connections

IO	1	2	3	4	5	6	7	8	tc
	m	h	a	a(d2)	a(d1)	nc	h	k	g

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	12.6	0.15	250	-3	1	58k	1.2

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 12 June 2007 {find valves by name}