Best used amp 6K;Gamut,Gryphon Krell ..

Here in Europe in my price range of 5000 to 7000USD you can have Gamut 250Monos, Gryphon Antelion, Mc Intosh MC602 AC, Pass Alep1 mono´s, Krell FPB 600, Rowland 8T? Wich amp is a great deal and best to drive my power hungry Audio Artistry Beethovens´main panel. Having no chance to listen to all ofthem in my own setup I need some advice.