The 12AV6 is a double diode triode designed for radio receiver applications. Typical use would be detector, AGC rectifier and first audio amplifier. As such it is one of the magic three superhet valves.

The family consisted of three variants of heater voltage: 3AV6 - 3.15 V @ 0.6 A, 6AV6 - 6.3 V @ 0.3 A and 12AV6 - 12.6 V @ 0.15 A. The design is an upgrade of the 6AT6 family and has the same pin connections and internal construction with the exception of a cathode connected screen around the cathode as it travels up from the triode to the diodes.

The triode anode is the grey area in the centre, the two bright verticals are the diode anodes seen end on. The box above the top mica is the screen and the support rod on the right connects to the cathode.

The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 47 mm tall.

References: Datasheet & ¹⁰⁴⁰. Type 12AV6 was first introduced^¶ in 1955.

 
Pin Connections

B7G	1	2	3	4	5	6	7
	g1	k	h	h	a(d2)	a(d1)	a

 
Absolute Maximum Operating Conditions^¶

Triode	Vh	Ah
	12.6	0.15

Thanks to Frank Philipse for supplying the above PDF datasheet