The Saga of Marconi Osram Valve
A History of Valve-Making
By Barry Vyse and George Jessop
REVIEWED BY LUDWELL SIBLEY
The Saga of Marconi Osram Valve is an extraordinary book by two long-term employees of Marconi Osram -- Britain's most important tube maker -- Barry Vyse and George Jessop. This new "Saga" is a welcome addition to tube lore and Gerry Tyne's classic Saga of the Vacuum Tube.
The book details the history of the company and its plants, starting from the Victorian light-bulb days and the joint venture of Marconi's Wireless Telegraph Company and the General Electric Co. Ltd. It covers the development of tube technology from incandescent-lamp practices to today's ceramic models -- not just the evolution of tube designs, but the progress in materials and manufacturing technology. Its main focus is the "glory" years up to 1958, although the Marconi-Osram (M-OV) valve held out until the last KT88 came off the line in 1988. The book is based on extensive files of original records and catalogs, and must have taken years to write.
The scope of tubes covered is essentially the whole range. Transmitting tubes, receiving types, audio devices (the PX4, PX25, KT66, KT88, etc.), tuning eyes, Tuneon indicators, radar tubes from World War II, the Catkin metal line, thyratrons -- they're all there. The "CAT" line of big water-cooled triodes receives great attention, as do other transmitting tubes. To provide insight as to why particular tube types were developed, the book covers the early history of the BBC and of the original radar defenses of the United Kingdom.
The book provides the first complete history of the "silica valve," an M-OV transmitting product unique to the British tube industry. With a bulb made of fused quartz and ten kilowatts or so of power dissipation, it ran with white-hot plate.
Packed with photos and catalog illustrations, the Saga depicts people, tubes, tube cartons, and design drawings. The photos, many in color, are a mix of original shots and new images. As a nice unifying touch, there are also photos and descriptions of the equipment that used the tubes -- classic broadcast radios, transmitters, and military gear from both World War I and II.
As an integral part of the company's history, there is coverage of day-to-day work life in a tube plant. The various expansion projects at the company's Hammersmith (London) factory are detailed, as is the construction just before World War II of a "shadow" factory away from the areas of Britain that were likely to be bombed.
The book mentions Marconi-Osram's partnership with RCA in the design of tubes, the result of partial ownership by the latter. A minor complaint -- there is no explanation of the apparent interchange of designs with Eitel-McCullough in later years. The outline drawing of the M-OV CAS1 bears a remarkable resemblance to the Eimac 4W20,000. The M-OV 4CX250B "surely" originated with Eimac, as did other tubes like the 4CW10,000. It also looks as if there were interchanges with Philips and possibly other tube makers.
This Saga is designed for ongoing reference use, as well as history. A list of sources cites published research material. An appendix with 25 tables gives the basic operating parameters of M-OV receiving tubes. Another lists special variants, like the A855 (a KT66 with top cap). A third appendix lists experimental tubes, some civilian, some important World War II military types. There are two indexes: one general, one by tube type.
To those interested in the radar tubes of World War II, the new Saga is effectively an affordable replacement for the now-rare 1990 book Metres to Microwaves.
To put it simply, this book is a significant addition to tube history. Professionally written, it is enjoyable and insightful. It will be a pleasure to anyone interested in the history of, or the collection of British tubes and equipment.
The Saga of Marconi Osram Valve is available softbound for $39 from Antique Electronic Supply, 480-820-5411; www.tubesandmore.com. It has 340 pages in a 7" x 10" format, with 350 plus photos, and 300 plus catalog cuts. Be sure to check the supplier for shipping information.
(Ludwell Sibley, Editor, The Tube Collectors Association, 102 McDonough Rd., Gold Hill, OR 97525, firstname.lastname@example.org)