Description |
The 12AU7 is probably the first Noval (B9A) tube ever, registered on October 18, 1946, in the Electron Tube Registration List, followed by the 2C51, registered on November 25, 1946.
From the Dowd-RCA archives, we learn that the 12AU7 was preceded by the experimental type A4498 from November 1945. The first lot of 300 units was scheduled for August 1, 1946. The official announcement was made on October 8, 1946.
Although announced on 10/8/46, we do not find any devices with this tube before 1948 and John W. Stokes also mentions 1948 as the first year of regular market introduction. Maybe there were technical problems - maybe in connection with the new base (and/or bulb T-6-1/2)? Since the official announcement letter was sent early in 1947 including JAN preferred tubes, we would like to offer the date of market introduction 1947, but since we show more than 330'000 models of all sorts and since more than 5000 of those models carry a 12AU7 but none with secure date is from 1947, we have to select 1948 because we offer the year of first mass production of models for that year in order to find misplaced ages of models . They get automatically listed if they don't fit with the first year of a tube or semiconductor in the mass market - which is devices (models), not single tubes.
Use in AF phase inverters, TV flip-flops, mixers, multivibrators, TV vertical deflection - similar to the larger 6SN7GT and 12SN7GT. Center-tapped heater permits operation at 12.6V 0.15A.
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