Sensibly equivalent¶ to:
The EF55 pentode is physically the big brother of the EF50 with which it shares common base connections. The EF55 is a single ended RF pentode with very high mutual conductance and a sharp cut-off. It was designed for video frequency use, probably in RADAR service, and its service code was CV173
It is an early all glass constructed valve with equi-spaced pins and a spigot for location into the valve holder.
The current rating places it as a power valve but it is designated for amplifier service with a medium anode impedance.
The outer aluminium shield is 33 mm in diameter. The overall length excluding the B9G base pins, is 79 mm.
References: Datasheet & 1040 Type EF55 was first introduced in 1946.
Absolute Maximum Operating Conditions¶
Updated December26, 2011.