The Sonic Impact or Teac are just shadows of what can be achieved. Add the Sharp SD-EX111 available on overstock.com for $85 (20 wpc, remote, and a CD player).

But these are all cheap examples of the digital technology. Folks get ed in with the low price and the DIY juices start to flow. Wayne at Boulder Cables mods the Teac or SI. Vinnie at Red Wine Audio mods the SI and Sharp. These guys improve connectors, power supplies, etc. to take these amps to another level. OTOH just pulling the center channel board out of the Teac is supposed to help it sound better.

For $500 you can get into seriously nice stuff. Too many folks spend $50 or so thinking that they'll try digital, but that's hardly a fair shake. (Who would write off all tube amps after an experience with a $100 tube amp, even if such a thing were available.)

With a battery powered DAC now I'm seriously looking into Vinnie's 6 wpc battery powered Clari-T.