Here is an audio amplifier circuit modified from one I got off EDN – Europe. The original was a single supply version with a cap. coupled output into 100 ohms. I beefed up the outputs for 8/4 ohm loads, made it DC coupled and used an OPA552 instead of a normal op-amp. What is interesting is that the bias current is set by just the 1000 ohm resistor. The schematic simulation is running around 72 ma. in each output device with no signal. DC output voltage is under 1 millivolt, no signal. I suspect that the bias isn’t stable if the supply voltages vary. Also, no attempt has been made to characterize bias thermal performance. It works OK. You get about 50V p-p before it starts to clip. Clipping behavior is not exciting. No oscillation is seen during clipping. Overall, it seems to be well behaved. R4 and R5 are there just to be able to measure output currents. They could be omitted. Frequency response and distortion is typical for any audio amp. Nothing special. R1, R2 sets the gain and it is an inverting amplifier. Just a curiosity at this point.