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.   
