If going for the Pass amp, go for the X250.5 for the Sophias. This is the newest version of the X250 and supposed to sound smoother in the highs and more natural than the older X250, although I haven't heard the X250 I love the X250.5 in my system.
Also, I would recommend a tube pre if you are going with solid state amp for the Sophias.
Also, I would recommend a tube pre if you are going with solid state amp for the Sophias.