LS5A Osram balloon of 1924 dull emitter valve made for audio amplification POVT39

Description

The Marconi-Osram described the LS5A  a dull emitter valve for audio amplification.

The valve was first produced in 1924 and the A means an improved version of the same LS5 valve.

However two versions were made; metal base of 1924 and bakelite version circa 1928.

Tested and working.