Stable ECL80 Amp? - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Sideband · 29th Nov 2022, 10:57 am

Quote:

Originally Posted by murphyv310

and the Pye V4 used them as a frequency changer, wonderful little underrated valves.

Well if you can use a PCF80 as a sound output valve why not use an ECL80 as a frequency changer.....?

Synchrodyne · 29th Nov 2022, 10:27 pm

Pye’s use of the ECL80 as a Band I TV frequency changer was described in IEE paper #1294 of 1952 May, “The Design of a Superheterodyne Receiver for Television” by D. H. Fisher and A. J. Watts.

The writers noted that that although the conversion conductance of the only available triode pentode (i.e. the ECL80) was less than half that of a typical TV pentode, nonetheless, in this case (with a high IF), it was better than either a self-oscillating pentode or a double triode frequency converter.

They then went on to say: “The authors note with regret that there appears to be no efficient triode-pentode available on the British market suitable for frequency-conversion service at the frequencies under consideration.”

The first American TV frequency changer triode pentodes, 6U8 and 6X8, had been released around 1951 August plus/minus, so the authors were probably aware of these. In the UK, the Mazda 10C2 would have been imminent, if not already released, at the time the paper was read, but perhaps unknown when it was written late in 1951.

Be that as it may, if the ECL80 could be made to work as a frequency changer at Band I, then perhaps it would also work at HF, which would make it a frequency changer candidate for the receiver concept that is the subject of the thread: https://www.vintage-radio.net/forum/...d.php?t=195648.

Cheers,

29th Nov 2022, 10:27 pm	#22
Synchrodyne Nonode Join Date: Jan 2009 Location: Papamoa Beach, Bay of Plenty, New Zealand Posts: 2,944	Re: Stable ECL80 Amp? Pye’s use of the ECL80 as a Band I TV frequency changer was described in IEE paper #1294 of 1952 May, “The Design of a Superheterodyne Receiver for Television” by D. H. Fisher and A. J. Watts. The writers noted that that although the conversion conductance of the only available triode pentode (i.e. the ECL80) was less than half that of a typical TV pentode, nonetheless, in this case (with a high IF), it was better than either a self-oscillating pentode or a double triode frequency converter. They then went on to say: “The authors note with regret that there appears to be no efficient triode-pentode available on the British market suitable for frequency-conversion service at the frequencies under consideration.” The first American TV frequency changer triode pentodes, 6U8 and 6X8, had been released around 1951 August plus/minus, so the authors were probably aware of these. In the UK, the Mazda 10C2 would have been imminent, if not already released, at the time the paper was read, but perhaps unknown when it was written late in 1951. Be that as it may, if the ECL80 could be made to work as a frequency changer at Band I, then perhaps it would also work at HF, which would make it a frequency changer candidate for the receiver concept that is the subject of the thread: https://www.vintage-radio.net/forum/...d.php?t=195648. Cheers,