Tubes

Identifying NATIONAL UNION tubes

This article provides examples of NATIONAL UNION-manufactured tubes. NATIONAL UNION was another quality USA tube manufacturer with most production dating from 1930s to 1950s. Their production numbers were significantly smaller than the big name brands (RCA, Sylvania, GE). The NATIONAL UNION (EIA) code number is “247″. Here is an example:

Identifying RAYTHEON tubes

This post provides examples of Raytheon manufactured tubes. Raytheon was an extremely high quality USA tube manufacturer with prolific output, covering both civilian issue and a vast majority of US Military parts production. The Raytheon (EIA) code number is “280″. Here is an example: