Robert Casey wrote:



If a tuning eye is fitted to this type of radio it is almost universally
connected to the audio detector rather than the AGC detector, which is
unfortunate from the AC loading point of view as the filter for the eye
tube often presents an even worse AC load than the AGC circuit.

Is that because of a resistor-capacitor filter between the audio
detector and the grid of
the eye tube? I would just feed the audio directly to the eye tube
grid, and place a
cap on the eye tube triode plate to do the filtering there.

The loading effects are removed when a CF buffer is connected to the last IFT
sec,
and the diode detection and eye drive voltage is derived from the low
impedance cathode
of the CF.

Patrick Turner.