I'd take a look at YS Audio / Audio Experience.
http://www.ys-audio.com/e_exp.htmI own an older version of the Balanced (level 3). Fairly well built with minimal parts and functionality you don't typically find at the price. Sounds good and IMO it's a VG value. I see them used at below your budget.
The Symphony (level 2) is the next model down and the new price is within your budget. I hear good things about it. Worth looking into.
Edit: the Eastern Electric MiniMax is also a great choice at about $500 used. Very musical and allows for fun tube rolling. Years ago owned the version with Tom Tutay mods, loved how it sounded. Sold it d/t lack of remote volume control.
