Vol. 11, No. 4

Volume 11, Number 4

The mount drawing for the now-eBaygenic “single-plate” 2A3 audio triode, with its 20 filaments. This original version carried a reputation for being hard to amke in terms of equal tension on the filaments, and was soon superseded by new designs. The note about the tensioning springs testifies to this diffuculty. Image: RCA Standardizing Notice 3-1-2A3, Sept. 13, 1934, in the Dowd-RCA Archive, a holding of the AWA Museum.

In this issue
  • Review: Where Discovery Sparks Imagination
  • Review: British Radio Valves – The Classic Years: 1926-1846
  • The “NationalSix-Pin Base
  • The “First” Transistor Amatuer Gear
  • Transmitting Tube Checker
  • Another Eimac Wannabe
  • De Forest in History
  • Harry Roome, Junior Salesman

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