Sensibly equivalent¶ to:
The 12AH8 is a triode heptode frequency changer. The triode oscillator couples internally to the heptode grid number three. The design is aimed at HF communications receivers where oscillator stability is important.
The triode oscillator runs with 100 Volts on the anode to generate a 9.4 Volt LO signal. The heater is centre tapped so that either a 12.6 Volt supply across pins 4 and 5 can be used or a 6.3 Volt supply across pins 4 & 5 together and pin 9.
The heptode is the lower unit with the triode mounted above the separating mica.
The thin glass tube envelope is 21 mm in diameter, and excluding the B9A base pins is 58 mm tall.
References: Datasheet, 1040 & 1043. Type 12AH8 was first introduced in 1953.
Absolute Maximum Operating Conditions¶
Updated November 28, 2014. shape:thin.glass.tube construction:all.glass type:triode.heptode age:1950.1960 base:b9a heater:12.6v pins:9 pin:1.g2.g4 pin:2.g1 pin:3.k.g5 pin:4.h pin:5.h pin:6.a pin:7.g1(t).g3 pin:8.a(t) pin:9.hct