standard voltage opamp driving output stage with gain.
while this is a functional amp it's not intended to be a production ready 1.2kw amp as no single transistor could cope with the power dissipation however it is a path forward to a design for such an amp. in reference to the bugger looking for high voltage opamp for his design this allows standard op amps to be considered.
their are things to be aware of the output current limiting is incorporated into the global feedback loop and should the output be driven into limiting this would cause severe distortion as the opamp would try to compensate by driving it's outputs into the rails and driving output stage with square wave signals.
this is only meant to be an example of how to design such an amp and more design would be needed.
