Randy,
Having owned almost everything, of course :audiophile:, I feel the KEF LS50 benefit more with an amp like the JOB as opposed to the Pass anything except maybe one of their Class AB type amps. The only other amp type I'd recommend for the LS50 is a moderately powerful tube amp, but I don't feel you want to go down that path. I feel those KEF, like Harbeth and similar benefit from a more open, lighter, airy 3D amp.