Category: Magazines

On The Cover RCA 5671 triode In this issue

On the Cover The Famed Umac 606 In this issue

On the Cover The Amperex 211G power Triode In this issue

On the Cover The Bell Labs type A transister, 1949 In this issue

On the Cover A pre-prototype leading to the Eimac 304T, from an affidavit filed by Ronald H. Gordon, laboratory glassblower. He certified having made the tube “before1940.” The objective was to contest, successfully, a claim of inventing a “plurality of grids in an envelope” in a patent application by Harold Zahl of the Signal Corps....

On the Covers Two halves of a composite four-tube photo, from the De Forest Radio Co. A 10-1/2 X 19-1/2 print of this image turned up in the recent Boyer Estate auction conducted by the CC-AWA group. This is quasi-historic stuff: spired article in Raadio News, May, 1930. In this issue

On the Cover A reproduction of De Forest catalog art: images of the 500 and 504A triodes. The artist’s originals can be yours, via the CC-AWA auction planned for March. See p. 1 for details. In this issue

On the Cover The Eimac X-4 developmental triode of June, 1942; one of many versions that finally led to the 527 radar tube. The anode is from the 250T. Filament drain is 7.5v@30A. In this issue

On the Cover A Western Electric 240A with the radiator and anode cut away to show internal construction. Note that the water inlet and oulet fittings are displaced from each other, presumably to induce a spiral flow of the colling water. Photo from the late Bell Labs Historical Museum. In this issue

On the Cover The Eimac X-O from early 1942, first of a numbered line of “X” developmenta types that eventually ran into the low thousands, and one of the umpteen possibilities that eventually yielded the 527 radar triode. It appears to use th eduel stacked anode assembly and grids from the VT-158 Zahl tube, in...