Amp for Thiel CS6

I currently am using a Conrad Johnson MF2500A to amplify my Thiel CS6 speakers. At times it seems as if the amp does not give as full, or solid a bass response as I would like. Is this a potential issue with the MF2500A? I am considering either a CJ Premier 350, or a Rogue Audio Zeuss. Any thoughts about these, or other amps with the Thiel CS6 speakers? Thanks.