Sensibly equivalent¶ to:
The Pen4VA was, eventually, the Mullard answer to the landmark Mazda AC/Pen of 1930 for audio output within AC mains sets. The photo shows a post-war specimen made for replacement purposes. Following a series of rather less successful attempts to make indirectly-heated output pentodes (Pen20) the successful but obsolescent Pen4BA was introduced with a B7 base cap (by then, after 1933, current) but B5 versions were supplied as replacements for its less successful predecessor the Type Pen4V. These were designated Pen4VA (5).
The classic envelope is 42 mm in diameter, and excluding the B5 base pins, is 113 mm tall.
References: Private communication & 1040. Type Pen4VA was first introduced in 1933.
Absolute Maximum Operating Conditions¶
PDF scanned from an original document held by the museum
Updated April 07, 2015.