I didn't want to include an A/D (with oh so easy to use 3 wire interface) but rather a choice of two raw analog signals. The signals are jumper selectable between raw AC coupled signal and a DC Detected signal that shows the envelope, which frankly is easier to use for low sample A/D.

Since I am a burn out, I make a mistake on every rev board, the trick will be to get the proto working anywas. :)