Odyssey Khartago and Stratos Amps, Plus versions, mono or stereo, also Belles Ref 350a. Rowland Capri v1 and Pass XP-10 preamps. Have not heard the Odyssey preamps. I liked recent Nuprime gear but have not heard their amp and pre in your price range. I do not like the A21, but this is simply personal preference, many great choices at your price point.
