Double triode 5963 MIXED AMERICAN BRANDS "NOS"

5963 "NOS" 9-pin, 6.3V. MIXED AMERICAN BRANDS (TungDol, CEI, Sylvania, RCA, Hewlett Packar)

The 5963 is a special quality double triode introduced in 1954 for use in computer where the tube will spend much of its time cut off. The centre tapped heater allows for the sections to be run in series (connect to pins 4 and 5 and run at 12.6V) or parallel (connect pins 4 and 5 together and feed at that junction and pin 9 with 6.3V). The thin glass tube envelope is 20mm in diameter, and excluding the B9A base pins is 49mm tall.

The 5963 is a beefy version of the 12AU7 that works on slightly different board voltages.