I owned the Avalon Eclipse in the past and they do have something special about them. Properly set up and with the right equipment and source material, they were truly holographic. I actually sold them to my brother at a deep discount just to keep them in the family.
I cannot comment specifically with regard to the two amps mentioned, though older Rowland amps were always suggested to me by those I trusted as great matches with the Eclipse. The Classe CA-400 amp did an admirable job; the Levinson ML27.5...not so much. My favorite was a Manley NeoClassic 250 and used this amp for most part.
Good luck...the right amp can really make those Eclipses sing!
I cannot comment specifically with regard to the two amps mentioned, though older Rowland amps were always suggested to me by those I trusted as great matches with the Eclipse. The Classe CA-400 amp did an admirable job; the Levinson ML27.5...not so much. My favorite was a Manley NeoClassic 250 and used this amp for most part.
Good luck...the right amp can really make those Eclipses sing!