I can't figure out how to do a differential amplifier with AC sources. I've built the generic DC one that I was taught in school (see attached image) but it's giving me weird values. For example, it's producing a positive voltage even when the negative terminal has a greater voltage.
My signals are primarily 10 to 22kHz. I would really like to do this with one op amp. Transistors are okay, but I'm trying to minimize the amount of connections that I would need to solder to a PCB.
The op amp is powered by a DC source (single supply, 5V).
Technically, these AC sources are oscillating DC voltages with a voltage offset originating from a headphone jack. What I mean is, the voltage oscillates from 0 to 1 volt. The changing frequency drives a coil next to a magnet inside a headphone. I would like to amplify the difference in sound coming out of the headphones (left minus right) and feed it into a circuit. It's on the order of 100 mW total power. I don't know whether this makes them technically AC or DC, but I'm assuming that this is what's causing the issues with the op-amp.