Krell FPB 400CX vs PASS LABS X-350.5


I'm moving up the ladder and have it down to these two amps. Any suggestions?? Should I go with the Krell FPB400CX or the PASS LABS X-350.5??

Speakers: DeVore Fidelity Nines
Preamp: Pass Labs X-1
Source: Esoteric X-03SE
Cables: Audiopath Silver 8 all around
roor
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.
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Ditto Tvad's comments. If you want to stick to solid state you could also consider the class A models from Plinius: SA-50, SA-100 & SA-02.... or Clayton S40 & M100
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I agree with Tvad and Pdreher. Based on my experience with earlier Pass class-A vs AB designs, including older Threshold models, if the XA-60.5 is remotely close in price to the X-350.5 go for the XA. It will sound enormously powerful on the Nines and will have subtlety and nuance the AB amp lacks.

Happy listening,
John DeVore