I laid out a small circuit board and built it up.? It seems to work quite well from the little I have used it.? Only thing I noticed was a decrease in total audio level.? I compensated for that by increasing the value of the capacitor between 1 and 8 on the LD386, I think I used a 4.7uF instead of the 1 uF.? Have not noticed any appreciable increase in the background noise.? Nice thing about it is you do not need to make any changes to the board, everything just gets tacked onto the volume control.? I plan on making some measurements of the audio response with and without the AGC when I get time.? But right now I am working on a si5351 VFO to get rid of the drivt problem.
DuWayne KV4QB
DuWayne Schmidlkofer