The EF11 is a variable μ pentode for use as an RF or IF amplifier in a superhet receiver.
We have the complete line-up of valves from the set this valve was used in. Frequency changer ECH11, IF amplifier EF11 x 2, demodulator, AGC detector and first audio stage EBC11, push-pull audio output EDD11 and rectifier EZ11.
The identification was painted on the side of both of the EF11s. Nothing was stamped into the dome.
The wide metal tube envelope is 36 mm in diameter, and excluding the footless base pins is 42 mm tall.
Reference: Datasheet. Type EF11 was first introduced in 1939.
Absolute Maximum Operating Conditions¶
Updated September 10, 2013. shape:wide.metal.tube construction:glass.disc type:pentode age:1930.1940 base:footless heater:6.3v pins:8 pin:1.g2 pin:2.g1 pin:3.k.g3.m pin:4.- pin:5.h pin:6.h pin:7.- pin:8.a