Kinergetics Research has a few amps under $500. They are out of business and a good value sound per dollar.
I bought an old Marshall Leach Heathkit amp for $250. I am rebuilding it now, but it is surprisingly nice sounding.
Sumo has the Polaris, they run about $300
Rotel, Parasound or Adcom from the early 80's can all be had easily under $500...Adcom 535 is around $200.
I'm sure a couple of Chinese amps are decent, Here is a quad knock off by Douk audio: https://www.ebay.com/itm/Nobsound-Classic-Power-Amplifier-Audiophile-Hi-Fi-Dual-Channel-Stereo-Amp-1...
I bought an old Marshall Leach Heathkit amp for $250. I am rebuilding it now, but it is surprisingly nice sounding.
Sumo has the Polaris, they run about $300
Rotel, Parasound or Adcom from the early 80's can all be had easily under $500...Adcom 535 is around $200.
I'm sure a couple of Chinese amps are decent, Here is a quad knock off by Douk audio: https://www.ebay.com/itm/Nobsound-Classic-Power-Amplifier-Audiophile-Hi-Fi-Dual-Channel-Stereo-Amp-1...