Sensibly equivalent¶ to:
The type VMS4B typifies the swansong of the screen-grid receiving valve with anode top cap. It is an improved, vari-mu RF/IF tetrode intended for domestic superhet receivers but it represents the final milestone on the road which started (barely 10 years earlier) with the Type S625.
VMS4B features a straight tube above the base to facilitate through chassis mounting. This exhibit is later after it was found that such screening was not required. The envelope widens out immediately above the base.
The Marconi branding of this M-OV valve. Note the internal bright gettering under the external zinc screening paint.
The classic envelope is 44 mm in diameter and, excluding the B5 base pins, is 108 mm tall.
References: Data-sheet & 1005 Type VMS4B was first introduced in 1933. See also 1933 adverts.
Absolute Maximum Operating Conditions¶
Updated November 13, 2021.