Category: Volume 9

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Volume 9, Number 2

Vol. 9, No. 2

On the Cover The Eimac X-1, a developmental triode from May, 1942, using the bulb and base of a 250T, with new anode and heavier filament taking 25 anps instead of 10.5. In this issue

Volume 9, Number 1

Vol. 9, No. 1

On the Cover Eduard Willi, Swiss tube-history author (see p. 2, depicted with a Signum G 2 H 34 rectifier. In this issue

Volume 9, Number 3

Vol. 9, No. 3

On the Cover The vanishingly rare GL-8009, a version of the 880 triode with two extra posts for the grid leads, introduced by GE in 1942. While “intended for television service’ on prewar tv channels, its frequency rating for full power was no more than that of the 880, or 25 MHz. In this issue

Volume 9, Number 5

Vol. 9, No. 5

On the Cover The Eitel-McCullough X-7 triode of mid-1942, one of many exploratory designs that eventually yielded the 527 radar tube. In this issue

Volume 9, Number 4

Vol. 9, No. 4

On the Cover The base-branding machine in the De Forest Radio Co. plant, ca. 1929. The five-pin basses rotate into contact with the branding die – the white object at lower center above the pipe elbow. Heated by a gas flame just below, it burns the De Forest script logo into the base. In this...