Class AB + C Power Amp

I picked up a cheap class D amp from AliExpress, and, while it sounded fine at first, it eventually started motorboating. Fixing it seemed like more effort and expense than making my own crappy amp, so I ended up doing just that.




Without wanting to offend AMB, this amp is sort of like a crappy M3 with some optimizations for driving speakers. Instead of MOSFETs on the output, it uses BJTs in TubeCAD's class AB + C configuration. Unlike the M3, the op amp runs on the same power supply rails as the power stage. No active ground channel, because those are silly.



In an effort to eliminate any big irrrnnn, the amp runs off a Mean Well SMPS, regulated down with a simple no-feedback MOSFET series reg / rail splitter (really). The MW supplies are nice because the switching frequency is low enough to be easily filtered/regulated, and the supply voltage is trimmable so that the voltage drop across the regulator can be minimized. I'll grab a second switcher to eliminate the rail splitter at some point.

It sounds like an amp I guess. Gerbers/boards available if anyone wants.