Sensibly equivalent¶ to:
The EL84 output pentode was introduced by Mullard in 1954. Here is version branded RTRA, and it is possible that this was a foreign made import distributed through the trade association.
This exhibit came in an RTRA box and still has part of the RTRA logo on the glass. The Radio Trades Retailers' Association was formed in 1942.
This is a true pentode and all three grids can be seen.
The thin glass tube envelope is 21 mm in diameter and, excluding the B9A base pins, is 71 mm tall.
References: Datasheet & 1040. Type EL84 was first introduced in 1953.
Absolute Maximum Operating Conditions¶
Updated September 06, 2017. shape:thin.glass.tube construction:all.glass type:pentode age:1950.1960 base:b9a heater:6.3v pins:9 pin:1.ic pin:2.g1 pin:3.k.g3 pin:4.h pin:5.h pin:6.ic pin:7.a pin:8.ic pin:9.g2