Sensibly equivalent¶ to:
The EBF80 is a variable μ amplifier pentode and a pair of signal diodes in the one envelope. Probably this was designed as the later EBF89 as final IF amplifier and AM detector. The other diode would provide AGC rectification.
The envelope has bothe the Mullard Type designation and the M-OV designation of WD709. Both appear on the box as well.
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 56 mm tall.
References: Data-sheet, 3002 & 1040. Type EBF80 was first introduced in 1950.
Absolute Maximum Operating Conditions¶
Updated March 19, 2014. shape:thin.glass.tube construction:all.glass type:double.diode.pentode age:1950.1960 base:b9a heater:6.3v pins:9 pin:1.g2 pin:2.g1 pin:3.k.s pin:4.h pin:5.h pin:6.a pin:7.a(d1) pin:8.a(d2) pin:9.g3