. 'Useful amount of power, low distortion and probably OK to lay out and build on stripboard or some other simple DIY technique. 'Pity about the rising cost of those Lateral Mosfets though - it's something like 7UK pounds each + postage.
No. Electrolytic capacitors are non-linear.
The current mirror U7 and U8 will not work with mismatched transistors. They need emitter degeneration.
I am pretty sure the simulator is assuming that U5 and U6 have the exact same Idss. You need to build a real amplifier.
Ed
The NFB would have to be split in DC (for operating point) and AC for reduction of distortion. The AC feedback should include both input and output C. In my simulations this works rather nice. In DC output coupling it still is useful to include the input C in the NFB loop. Those with fast prototyping ability could measure the difference.
