I might recommend an Audia Flight FLS9. High damping factor and low distortion command the Evoke 20's low impedance woofer and fully reveal the potentials of its tweeter. For a slightly less detail-forward integrated, I might recommend the Prima Luna Evo 300 – great, easy to live with tube sound.
I have owned the high end integrateds from Pass, Musical Fidelity, Octave, Marantz, Ayre, and many others, and those would be my picks for those speakers.