PASS LABS X250 vs X150.5

The other way around. The .5 series is more refined. I have heard the 250 and personally didn't care for it with my speakers. It is a very very nice amp with loads of bass and resolution. It just had too much resolution for my taste.

IMO,I agree with Samzx12..but for the Wilson I would go tube!!!

Why not sell the X-1 and buy the INT150 which has an amp section based on the X150.5 and a pre amp section based on the new XP-10? Contact mark at RENO HiFi. One box and the sound should be superior. I have not heard it, but I did have the X-1 and now have an XP pre amp. I believe the X.5 amps are more refined than the X amps.

I think the Sophias will benefit from tubes somewhere in that chain... primarily in preamp or amp (s).