Integrated amp to match with jmlab cobalt 807

Albeit, maybe a little more expensive, but try the Creek 5350SE. It is a knockout!!!

I have owned both the NAD C350 and an Audio Refinement Complete. Both are "good for the money". The Audio Refinement looks and feels nice, and sounds like a good ss amp. The NAD offers slightly less resolution but a slightly more forgiving sound and more features. Neither of the above were keepers for me. I realize you have ruled out tubes, but if you want the best sound I would try auditioning a tube integrated amp or entry level tube separates. My reason for saying this is I believe I have heard an older version of your speakers and I believe their tonal balance would match up well with a tube amplifier.

I personally (for my tastes) would consider a warm/mellow int. amp with that
loudspeaker. Consider Audio Analogue "Puccini" ,Jolida JD
1301,1501,102/202, Unison Research to name a few. Try to audition in your listening room with your equipment if possible. Good luck! Bill