A Sumo Athena can be had for $200 to $300. It is better than any Adcom other than the GFP-750... You could find an Old B&K for that price or as mentioned above, a decent passive could be found in that price range.
I suspect, this sounds pretty good. I'm familiar with this volume controller.
http://www.ebay.com/itm/NEW-PGA2311-Stero-Remote-Volume-Controller-audio-Preamp-pre-amplifier-with-MUTE-/141447354247?hash=item20eeeb5787:m:mcHZDPREyeAV4jRgjH4f4FA
I suspect, this sounds pretty good. I'm familiar with this volume controller.
http://www.ebay.com/itm/NEW-PGA2311-Stero-Remote-Volume-Controller-audio-Preamp-pre-amplifier-with-MUTE-/141447354247?hash=item20eeeb5787:m:mcHZDPREyeAV4jRgjH4f4FA