Where to buy high current linear amplifier?

I am trying to find details on high current linear amplifiers to drive high power electromagnetic coils, but cannot find anyone who sells them, and I'm not really sure where to look. I would ideally like an amplifier that can provide some 2 kW into a 10 ohm load, around 10-20 amps. It would need to amplify an arbitrary signal input (DC, sine wave, square wave, etc) up to 500 Hz. I was considering using high power audio amplifiers, but I do not believe they work at DC. Any pointers would be great! (and I do realize this sort of amplifier will likely cost several thousand $$).