Sensibly equivalent¶ to:
The 10LD11 is a double signal diode triode with a common cathode. This configuration was typical of valves designed for superhet receivers. The diodes would be used to demodulate an AM signal and also to develop an AGC voltage to control the gain of the IF amplifiers and possible the RF amplifier if fitted. The triode would function as a voltage amplifier for the demodulated audio signal.
The 10LD11 is pin compatible with the 10LD3 but this is a much uprated version. The 6LD20 is equal to the 10LD11 but has a 6.3 Volt 0.25 Amp heater and is designed for parallel heater supplies.
The second picture shows the anode and the type designation lettering.
The thin glass envelope is 19 mm in diameter and, excluding the B8A base pins, is 55 mm tall.
Reference: 1040. Type 10LD11 was first introduced in 1947.
Absolute Maximum Operating Conditions¶
Updated April 07, 2013. shape:thin.glass.tube construction:all.glass type:double.diode.triode age:1940.1950 base:b8a heater:100ma pins:8 pin:1.h pin:2.a pin:3.g1 pin:4.s pin:5.a(d2) pin:6.a(d1) pin:7.k pin:8.h