Quote:
Originally Posted by Synchrodyne
Thus, the 6U8 was also the first multipurpose TV triode-pentode.
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That was not quite right. The Philips ECL80 preceded it, and was a multipurpose TV valve even though it did not cover frequency changer or IF amplifier applications. The ECL80 dates from 1949 or 1950. The earliest reference that I have is for the Mullard version in Wireless World (WW) 1950 May, p.195. It was mentioned along with the EF80 as a being a new TV valve, but then the EF80 had had previous mention in WW 1949 November, p.440.
Also, the 6X8 and 6U8 frequency-changer triode-pentodes might have been preceded by the Mazda 10C2, with a 100-mA heater and on the Rimlock base. However, I havenÂ’t found any information as to when this valve was released. WW 1949 November noted that Mazda had a new range of 100 mA heater TV valves. (There also were some with 200 mA heaters). The 10C2 was not mentioned, but then the full range was not listed, so it could have been amongst them. Possibly it was intended for use as a frequency changer for Band I-only superhet receivers, as an alternative to say a self-oscillating 10F1 pentode. Thus, it may not have been designed with Band III capability in mind.
Quote:
Originally Posted by Synchrodyne
RCA also developed the 6AM8 TV diode-pentode.
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Sylvania might have been first with the 6AM8. It was described as being a combination of a 6CB6 with half of a 6AL5. RCA contributed the similar 6AS8 TV diode-pentode.
Cheers,