I'm trying to make a simple microphone/speaker circuit with a
PreAmp and an
Op-Amp. Currently, the speaker just outputs a high frequency squeal, and not anything from the microphone.
Looking at the schematic, is there anything you can see that I've done wrong?
Preamp (INA217) http://www.ti.com/lit/ds/symlink/ina217.pdf
Op-Amp (OPA1652) http://www.ti.com/lit/ds/symlink/opa1652.pdf
I've discovered some good news and some bad news. First, the good news! I've eliminated the high pitched tone from the speaker by connecting pin 1 of the MAX1044 to pin 8. The bad news... the circuit still doesn't output any sound from the microphone. So, I've simplified the circuit to try and isolate the problem:
More good news! Eliminating the OPA1652, I get actual audio from the microphone through the speaker and can adjust the mic gain with the pot and actually gets quite loud on a cheap pair of earbuds.
Revised question: Where have I messed up when it comes to the OPA1652 and how should I wire it differently?
For what it's worth, the end goal is to make a small audio mixer. Multiple mic inputs and a single output signal.