Help! Best amp for Rockport Aviors?

I recently purchased a pair of Rockport Aviors to replace my Dynaudio C2s. My system comprises of a Berkeley Reference DAC, Spectral DMC-30SS preamp, and Spectral DMA-260 stereo amp. My intial impression was disappointing - "hot" treble and a lack of low end slam. I assumed that my amp didn't have enough current to drive the Aviors properly so I auditioned the Spectral DMA-400 RS monos with the Aviors and that combo still didn't resonate in the way I first heard the Aviors (kicking myself for not noting the system). My current theory is that the Spectral gear (as much as I love it) isn't a good match for the Rockports; therefore, I have a bit of a quandary - ditch my Spectral system or the Aviors.

I know that Andrew uses a Gryphon stack to voice his speakers. Correct me if I'm wrong, but I don't kmow of a USA Gryphon dealer and wouldn't purchase a Gryphon component without hearing it in person first.

So cut to the chase: Avior owners out there - what do you drive them with that results in the "softer" treble and bass slam that I know these speakers are capable of. My current guess is to audition Pass Labs.