This is a very interesting thread. I guess I've been working in a vacuum too long. I always have to learn the hard way anyway. I doubt anybody's interested in an oversimplified and feature-free controller but I thought I'd post a short clip of the waveform of the pre-amp stage (this feeds into the power mosfets). It is running at 20khz. I wish I could show you the final mosfet stage but I burned my test mosfet up and I'm waiting on replacements.