By the way, using the LM386 as the amplifier for the AVR ADC input was extremely clever.? Thr LM386 inputs are ground referenced but the output internally is vcc divided by two which on 5V will properly bias the ADC inputs at 0 to 5V.? I think I might modify my ADX-S with this modification by modifying a commercial SMT device "microphone" amplifier module by removing the input DC bias resistor for the mic and the output components to drive a speaker on that board. Maybe grind down the physical size of the board on the output side.? ?The only difference then on that board would be an additional bypass cap on vcc and it being configured as a non inverting amplifier instead of inverting which I imagine would still work. (and if not would be easy to further modify.)?
What a great little modification to an already fun little rig.?
Fred W0FMS/7
Fred Spinner