As a untutored amatuer may I offer this Quote for comment," when conventional transistor amplifiers enter undefined operating regions the amp clips and feedback loses it's grip on the amp. Conventional designs use feedback to compensate for gain transitions and absorb back EMF from the drivers. Speaker drivers are always creating back-EMF as a result of numerous resonances, many with very high Qs and long time durations. When a conventional amp clips, the source impedance seen by the driver suddenly changes, and the back-EMF is suddenly reflected back to the driver instead of being dynamically absorbed by feedback correction. So although a conventional feedback amp may look benign clipping into a resistive load, things get a lot uglier with real world speakers, and no speaker driver is going to be happy with a power source that has sudden transitions in the driving impedance." Any help with this one?