I found the PASS X250.5 to be noticably quite superior to the Krell FPB-300cx when compared side-by-side. I would assume that the same would go for the next models up. The PASS X.5 series is 5+ years newer than the old Krell FPB series. I found the Krell Evolution Stereo Amps to be sonically very competitive with the PASS X.5 (& XA.5) Stereo Amps.
