There are several Heath amps that put very nearly 1 kw on the outlet. The AA1640 comes right to mind, as it, in mono, makes 800 watts into 4 ohms. circuit losses of 200 watts or so does not seem unlikely.

My Harman Kardon Citation 16 draws close to 12 amps @ 120 VAC at full load, making 1,440 watts. Not that it has ever been driven to that extreme - but it is just possible.

Dynaco 416, Phase Linear 700, Crown CE1000. There are a good many brute-force amps out there, not accounting for quality, just force.

Peter Wieck
Melrose Park, PA