[Synchrodyne]

Originally Posted by GrimJosef

I'll mention the EF184. The valve museum says they were "purpose designed" and quotes Mullard's description: A frame-grid sharp cut-off pentode for use as an IF amplifier in television receivers. Sadly, there's been an awful case of "audio aficionados trying anything they can get their hands on" which has resulted in these being used NOT as IF amplifiers in television receivers !!!

Fortunately the audio aficionados (i.e. beasts) who perpetrated this wickedness have been identified. Their names were Arthur Radford and Arthur Bailey (there's another pair of Arthurs for you Andy). The scene of the crime was the phase-splitter of their STA100 amplifier, which dates from 1967 I believe https://www.radfordrevival.co.uk/literature/sta100/.

Since neither man is still with us I'm not sure how retribution can be exacted. Does anyone think we might, um, just this once, let it go ?

Ah, but Arthur and Arthur already had form. Bailey had used the ECF82 in his new audio phase-splitter design that Radford then used in his STA25 amplifier.

ECF82 was the Pro-Electron designation for the 6U8, developed by Tung-Sol in 1951 for use as a VHF TV triode pentode mixer-oscillator, but also said to be suitable for many other TV receiver functions.

The similar early TV triode pentode from Philips was the ECF80/PCF80, primarily a mixer-oscillator, but also said to be suitable for various other functions that were specifically delineated. The other applications for the pentode section included audio output.


Cheers,