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
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
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...
The Western Electric 7C22, a packaged push-pull radar oscilator. See story on p. 16 In this issue
Daniel Stocks, Australian microwave-tube expert, left visits Ron Lawrence and his “Radio Heaven” display in North Carolina. Photo: Robert Lozier. In this issue
On the Cover The Eimac X272 developmental tetrode from 1944 – a 4-125A with three radial pins added to reduce lead inductance. In this issue
The Eimac X-8 triode of July, 1942, one of the Umpteen proto-types that led to the 527 power tube. In this issue
On the Cover This appears to be British Post Office “Valve Amplifing No. 1,” made by BTH, as discussed in Keith Thrower’s British Radio Valves – The Vintage Years; 1904-1925. The photo is of a sample in the long-abolished tube museum at Bell Laboratories. Photo: Bell Labs, courtesy of Jerry Vanicek. In this issue
Removing sealed-off tubes from a small Sealex machine at the De Forest Radio Co. plant in Passaic, NJ, about 1931. In this issue