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.
droz
I would throw the Mark Levinson 300 series of amps in the mix also. I've had good results with the 331, but moving up the line would offer ever greater power and control over the Thiels.