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Just a somewhat standard symmetrical topology.
The trick is in using the output to bootstrap the supply rails of the preamp and driver, as to be able to drive the MOSFETs into their linear loadline's maximun. Sort of like making the preamp work in class G/H and the output stage in class AB. Typically MOSFETs have around 3-4V of Vgs voltage drop, and the driver is not capable of rail to rail driving, and considering the 0.5V voltage drop from the 100mOhm resistors, we're looking at a 6-7V output below the supply rails. That's just a waste for me. So by bootstrapping the supply rails, we're allowing them to run at higher voltages (in respect to ground), which helps with increasing the Vgs drive voltage of the MOSFETs.
P.S. A similar trick can be employed on the supply rails of the MOSFETs themselves, with an external amplifier, like a Class D module or something, with the same 30V voltage sources, but it would require some substantial redesigning. Basically turning the Output stage into Class G as well.
THD is 0.5% @ 1kHz @ 100W
Drawn Power - 138W
Output Power - 100W
Efficiency - 72%
Note about THD - 0.5% is measured with an open loop gain of around 300 for the whole amplifier. With the 100ohm emitter resistors bypassed, the open loop gain becomes ≈3000 and the distortion improves at 0.05%, but stability issues may arise due to the high gain.
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