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Moorhead Laboratories Tubes |
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| Otis Moorhead
started his tube manufacturing business in 1916, making one of the
copies of Cunningham's AudioTron,
which he called the "Electron Relay". He also made tubes
under contract to the US and British Governments during WW-I.
After the war, the ongoing patent wars between DeForest (owner of the grid patent) and Marconi (owner of the Fleming diode patent) rendered the legal manufacture and sales of tubes nearly impossible. Occasional deals were struck, however, and it was under one of these agreements (in 1919) that Moorhead was able to manufacture the tubes shown here, with the limitation that they licensed only for "Amateur and Experimental" use. The four tubes shown here were made in 1920. The first two are examples of the "VT" type, a high-vacuum amplifier and detector. One used gold tinted glass and the other used clear glass. The last two are examples of the "Electron Relay", a soft (low vacuum) detector, with two different internal configurations. Some of these tubes had both DeForest and Marconi markings on the bases, steel-stamped into the brass. Most had etched markings on the bulb, and all had serial numbers. |
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