This audion was made by McCandless for De Forest in 1913. It has a single control grid and anode but a double Hudson filament.![](../pics/aco0056a.jpg)
The base of the original box. Thanks to Joe Gruber for sending the images.The balloon envelope is 50 mm in diameter and, excluding the base, is 76 mm tall.Reference: Joe Gruber. Type Audion was first introduced in 1911. See also 1911 adverts. |
Updated September 22, 2020.
|
|