The VMS4 variable μ screened tetrode dates from 1931. It was designed for RF and IF amplification in broadcast superhet receivers.

This M-OV valve is badged as Osram suggesting it was made for domestic use.

The narrow tube before the flare would allow for a horizontal mounting with a chassis screen in just the same was as the original S625. Our other examples of the glass VMS4 and VMS4 lack this feature. We also have the 1933 Catkin version VMS4.

This is an early example with the screw down top connection. Later production used the top hat top cap.

The Osram brand.

The balloon envelope is 45 mm in diameter and, excluding the B5 base pins, is 122 mm tall.

References: Data-sheet & ¹⁰⁰⁵ Type VMS4 was first introduced in 1931. See also 1931 adverts.

Pin Connections

B5

1

2

3

4

5

tc

g2

g1

h

h

k

a