Hi mister_e,

After looking through pages of information on rectifyingand using the PIC I am not sure it is the correct or easiest way to handle what I am trying to accomplish.

What I want to do is take the AC signal from the speaker wires and then use this to turn on an aftermarket amp. I was originally thinking that rectifying the circuit would do the trick, however I am not so sure anymore.

I am now thinking about using a comparator circuit like you have mentioned to do. However, I have two concerns with this though:

1. All the comparator circuits that I have looked at use one wire as input, whereas, it is two wires that come from the speaker. Do I simply ground the negative wire from the speaker and run the comparator with the positive wire?

2. Since the voltage on the speaker can be as low as 50 mV can an op-amp comparator circuit use this low of a reference voltage for comparing? (To keep the amp on when there is a 50 mV or higher signal present)

Thanks for the help,
Michael