Antique Tubes and Their Equivalents

Oftentimes I see postings in the radio newsgroups from people that are not sure if, for example, the globe type CX301A is equivalent to the generic type '01A. The short answer is "Yes". Before about 1932, three digit numbers were assigned to receiving types, and in some cases, the first digit signified the company. RCA's numbers were "200" numbers, and most small companies defaulted to these. As far as the other major players, Cunningham used "300" numbers, DeForest and Sparton used "400" numbers, and Arcturus used "100" numbers. Below is a table summarizing the equivalents, along with giving equivalents for some peculiar lettered types. Note that none of the Western Electric types with similar numbers are equivalent to these standard types below.