Scott engineers first incorporated Compactrons, in 1962 into the
370-series (and LT-111, kit version) "entry-level" FM-MPX Stereo
tuners, and later in 1964, with the Type 345 FM-MPX Stereo receiver.
Compactrons are multi-function tubes, combining diodes, triodes, and pentodes in
various combinations, designed to reduce size and component counts in
entertainment and industrial devices. Compactrons have 12 pins arranged around a
3/4-inch diameter base. Tube dimensions are 1-1/8 inch diameter and overall height
ranges from 1 inch to 2-3/4 inch depending on tube configuration.
In the early 1960's, tube designers still had a few tricks up their sleeves. General Electric's Owensboro, Kentucky,
engineers introduced the "Compactron." GE engineers
claimed a two-Compactron radio design could replace a standard five-tube radio
complement (seven transistors were needed for the same performance), or a
10-Compactron TV-set could replace 15 tubes and three diodes or 24 transistors
and 11 diodes. A seven-Compactron stereo design could replace 10 tubes or as
many as 26 transistors. American tube designers clearly hadn't yet thrown in
the R & D towel, even as the "space-age" was dawning.
Several metallurgical advances enabled GE engineers to claim a 40
percent reduction in heater power. "A multi-function Compactron will
eventually sell for 20 per cent less than an equivalent number of tubes,"
according to GE marketing officials. (Electronic
Design, July 20, 1960, p. 74).