The Catkin version of the VMS4 variable μ screened tetrode dates from 1934. It was designed for RF and IF amplification in broadcast superhet receivers.The printed information gives the Type designation. The sales brand would be indicated by a paper label - missing on this exhibit.![](../pics/acl0196a.jpg)
The bronze finish on the outer screen. The oval shape where the paper label was one placed is the right shape for the Osram consumer brand.![](../pics/acl0196b.jpg)
The screw top cap was common in the early 1930s. Punched into the screen are the words Patented and made in England.![](../pics/acl0196c.jpg)
The base pins, slit and compressed to bow out at the centre to grip the holder and make a positive connection.The wide metal tube envelope is 33 mm in diameter and, excluding the B5 base pins, is 107 mm tall.References: Data-sheet & 1005 Type VMS4 was first introduced in 1931. See also 1931 adverts. |