There are some cheap, cheap $40 car subwoofer amps suggesting around 1,000w or more. I bought one (PA-80D) to pair with a decades old but very capable DELL 1,100w PSU from a server -- something you can find for $20 from one of many server liquidators. I received the amp and found 8 switching devices, emailed the seller, and was told that it uses the Toshiba 5198 1941 chipset and does around 300w RMS. It seems like a well-built unit and for $60 all-in, decent value for 300w RMS. I'm still looking for a budget 1-2kw solution...
