Vacuum Tubes 1915-1930
From 1915-1930 the major USA players in the production and distribution of vacuum tubes were, Western Electric (AT&T), RCA (General Electric and Westinghouse) and De Forest. These companies were in constant lookout for "copy cats" or "bootleggers" that violated the various patents originated with De Forest and J A Fleming. These companies even fought among themselves due suspect infringement of patents. Shown below are samples from my collection of early vacuum tubes from the big names and several bootleggers. An excellent reference on the history of the vacuum tubes and the growth of the electronics industry is Gerald F. J. Tyne's book "Saga of the Vacuum Tube" originally published by Howard W Sams Inc. A video of the early days of radio and vacuum tubes is PBS's "Empire of the Air". It is important to note that the construction of early vacuum tubes is mostly done by hand. Truly a work of art!
Last version on right WX-12 for prong insertion.
UX-213 (1925), UX-281 (1927), UX-280 (1927)
SHOWCASE
Vacuum Tube Version of the Integrated Circuit
The GE Compactron 1960-1975
The transistor in 1960 was still an expensive component compared to vacuum tubes. General Electric engineers designed a lower profile but larger footprint vacuum tube that could contain as much as 5 separate vacuum tubes in an envelope. They patented the design and named it the Compactron. The Compactron is a 12 pin vacuum tube with the base design similar to the 7 and 9 pin miniature tubes. These tubes were designed for PC mounting and were mainly designed for television. Television makers can now reduce the tube count from say 12 to 6 and if any transistors were used to 3 or 4. It help reduce production cost and kept vacuum tubes in production for at least 5 years. During this transition period, TV's were hybrid using both tubes and transistors. Often when you turn on a 1960's TV the sound would come on instantly and you had to wait about 20 seconds for the picture to come on. Often it is probably a hybrid TV. Many television manufacturers would taut being "transistorized" or "solid state", but they still had maybe two or three Compactron tubes. The damper and horizontal output tubes were the hardest to replace with transistors because of large pulse handling requirements. Many Compactrons were combo damper/horizontal output tubes like the 33GY7 and 38HE7. If you took the time to study the tubes, they were established tubes stuffed into one envelope. Example is the 6B10 tube data sheet on the left. It is basically the design of the 6AV6 tube triode and diode parts.
1963 Advertising of General Electric Televisions using the Compactron Tubes.
ABOVE AND LEFT: 1963 General Electric M110YBG Television shows how Compactrons allow manufacturers to make portable TV's smaller. 9 Tubes instead of 16-19 tubes are used, along with transformerless power supply.
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