07-09-2025, 08:12 PM
(07-09-2025, 05:05 PM)Mark Hennessy Wrote: X1 is a dampening diode. It increases the range of gain reduction the AGC can achieve before reaching the point where the transistor is no longer working in class A. I mentioned them earlier (post #12).
This is one of my favourites: https://www.worldradiohistory.com/UK/Mis...s-1960.pdf
Page 199 (72 of the PDF) talks about AGC with and without the dampening diode (see figure 5).
Yes, that's a lovely little booklet. Added to my library. Thanks.
Though in the Philips/Mullard cct, the diode is from emitter of IF amp to the IFT on the mixer. I suppose X1 does the same thing, but it is reversed as it's from the IF Amp collector to the Mixer's IFT. Most of the radios I have of that era don't have it.
