Sensibly equivalent¶ to:
The EL41 is an early all glass output pentode. Mullard describe the EL41 as an output pentode rated for 9 watts anode dissipation, and intended primarily for use in AC mains operated equipment. They state that the EL41 should only be used with self-bias or semi-automatic bias.
Unlike the first B8A valves that had a metal base cover with locating spigot, this valve has a wider base to the envelope and a locating pip moulded into the glass. It indeed represents the transition point to the final all glass valve. The pins are still equi-spaced in the base and this soon gave way to the B9A and B7G styles that did not require a locating spigot.
The thin glass tube envelope is 20 mm in diameter and, excluding the B8A base pins, is 65 mm tall.
References: Data-sheet & 1040. Type EL41 was first introduced in 1947.
Absolute Maximum Operating Conditions¶
Updated January 29, 2013.