Sensibly equivalent¶ to:
6BD7 6BD7A 6LD13 EBC80
The EBC81 is a double diode triode with the triode designed for audio amplification. The diodes share the same cathode as the triode and would be used for signal detection and AGC rectification.
This Pinnacle branded valve looks very much like a Mullard original product.
The screen hides the details but the triode grid is at the top and their is a central mica disc and so the diodes are below the triode.
The thin glass tube envelope is 20 mm in diameter, and excluding the B9A base pins is 53 mm tall.
References: Datasheet & 1040. Type EBC81 was first introduced in 1954.
Absolute Maximum Operating Conditions¶
Updated January 28, 2017. shape:thin.glass.tube construction:all.glass type:double.diode.triode age:1950.1960 base:b9a heater:6.3v pins:9 pin:1.a(t) pin:2.g1 pin:3.k pin:4.h pin:5.h pin:6.a(d1) pin:7.s pin:8.a(d2) pin:9.ic