The MS4 is an RF tetrode describes as a general purpose screen grid valve. It was available with and without the external zinc paint coating.
This exhibit was made in the mid 1930's or later, whereas MS4 is original. this exhibit has the top hat top cap rather than the screw cap used at the end of the 1920's and the classic shape is also a mid 1930's introduction.
The MS4B introduced in 1931 has an ra of 0.35M and a gm of 3.2 and was described as a high conductance screen grid valve for use where maximum amplification was required.
The reverse carries the Osram name in the coating.
The classic envelope is 48 mm in diameter, and excluding the B5 base pins is 117 mm tall.
References: Datasheet, 1040 & 1043. Type MS4 was first introduced in 1929.
Absolute Maximum Operating Conditions¶
Updated April 04, 2015.