|(Taken from the Preface on page VII)
This manual is an attempt to put together into one book, data and photographs of vacuum tubes long considered obsolete and to make information available to the collector. It would be nearly impossible to list all manufactured types and many are not listed. This manual is primarily concerned with types and the development of those types the reader is likely to encounter or be curious of.
Before the Radio Manufacturers Association numbering system became standard, confusion reigned supreme. Manufacturers were free to name their tubes however they wished and this resulted in tubes designated as the same type, but not interchangeable. An example of this is the Raytheon type B gas filled rectifier and the Ceco type B (equivalent to a UV 199). Probably the most horrific example of this are the non-interchangeable UV 201s made by Westinghouse Lamp Co. and Westinghouse Electric and Manufacturing Co.
Trying to make some sense out of this and develop a logical progression through the numbers is difficult at best and the author has chosen to follow the RCA numbering system for the most part. A Sylvania SX 201 A, Cunningham CX 301 A and an RCA UX201 A are interchangeable and will be found under the number UX 201 A, near the beginning. An RCA UX 222, Sylvania UY 222 and an Arcturus AC 22 are radically different and are therefore listed individually. By the early 1930s, most manufacturers had dropped the prefix and first number. The transition from alphanumeric nomenclature to double digit might also lead to some confusion. The 32 was originally introduced by RCA as the UX 232, but quickly became known as the 32, hence it is listed as the 32.
The photographs of the tubes and boxes are not necessarily mates since the author has tried to show the variety available at that time. The carton is appropriate for each particular type and that type can be found in the style and manufacturer's box shown.
Listed are some rare types, but samples to photograph were not available. Also some rare types are shown for which published data is nonexistent. Several of these tubes were tested with an AVO Mark IV dynamic mutual conductance tube tester. Please do not take this data as gospel as the actual condition of the tested sample is unknown and an insufficient number of tubes were available for comparison. The author was unable to find published data for the Arcturus AC 26, nor was he able to find a sample with an intact filament.
The data compiled herein is taken from manufacturers data sheets, previously published tube manuals, tube cartons and in several cases, the ARRL Radio Amateur's Handbook. A complete bibliography may be found on page 193.