the Reprocessed Tube Racket

“Standard Brand“, “Rad-Tel“, “Atomic“, “Cosmic” — what kind of brands are these? I found an interesting tube-related article in the Dec-1955-Jan-1956 issue of NATIONAL RADIO-TV NEWS.  The article exposed a supply-chain problem during the 1950s where unscrupulous vendors would buy “pull-outs” (duds or near-end-of-life tubes) from repair shops, then manipulate the tubes in a manner […]

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RMA Tube Numbering Code

I am frequently asked to explain what all of the “letters and numbers” mean in a vacuum tube number.  In the early days of radio, tube numbers were haphazardly assigned to new tube types.  As more vacuum tube types were developed, it became more difficult for technicians to recognize any fundamental characteristics about a tube. 

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