@erikt You're right, I should have been more clear in my original post. First of all, I want to make sure that I absolutely loved the Cronus Magnum II when it was in my home office driving the Harbeth P3esr's. I had rolled some tubes to tailor it to my liking and was completely satisfied with the sound. Hope nobody interprets this post as a knock on the Cronus Magnum II. In fact, once I get another amplifier for the media room, the Cronus will be back in my home office and stay there for a very long time.
Now, when using the same amp in the media room with the Sonus Fabers, it does get plenty loud, in fact I've never gone above the 11'o clock position on the dial. The issues that I am having (some of them have been mitigated to some extent though, I'll tell you why later) are ...
Bass is not as tight or punchy -- I'm working with GIK acoustics so let's see if that helps. But I can tell the amp does not have as much control on those woofers.
Soundstage depth and imaging -- not as good as I was expecting. Definitely the nice 3D holographic image that I was getting in the study is missing, imaging or placement of instruments is not as precise or locked in. Also, the sound is less fleshed out.
Vocals -- not as centered or forward as before. On some recordings, I expect the singer to be standing a few feet ahead of the rest of the musicians, but right now it's rather 2D. BTW, this is one area where I miss the harbeth sound sooo much!
Refinement -- there is just a general lack of refinement and liquid sound. Instruments suddenly jump at you out of nowhere, and not in a good way if you know what I mean.
So in summary, it's not necessarily the lack of volume that's bothering me, but all the other aspects that I mentioned above.