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.
Thanks to Michael for sending the photograph. Michael says that the EBC81 was used in his Nordmende Tannheuser stereo radio that dates from the 1960's. In this application the diodes were probably used as AM detector and AGC rectifier. A separate valve would be used for the FM demodulator.
The thin glass tube envelope is 22 mm in diameter, and excluding the B9A base pins is 55 mm tall.
References: Datasheet & 1040. Type EBC81 was first introduced in 1954.
Absolute Maximum Operating Conditions¶
Updated March 20, 2014. 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