Re: ECF82 frequency changer
I wondered if the 10nF (sorry, 0.01uF...) connected to the pentode cathode ought to be connected to the triode cathode (rather than ground) for low-impedance injection from a low-impedance point in the oscillator circuit, but I also can't help feeling that that would be excessively damping. Additionally, is it wise to involve an unspecified "RFC" in an oscillator tuned circuit? I could accept the presence of such a component if it was isolated by active device action, e.g. loading the triode anode but I would still be wary of it encouraging unwanted modes, aperiodic resistive loading seems less likely to cause puzzlement.
It won't be the first time I've looked at circuits in this kind of publication and thought, "Has anyone actually tried it to see if it works, and even if it does, is it anywhere near optimal for the sake of a little simple reappraisal?"....
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