I'm one of about three people in the world who are running twin Pathos Classic One MKII (I believe you can use any of the Classic Ones to do this, but on first version must open up the bottom to switch to mono) tube hybrid integrateds bridged to mono. A simple switch on the bottom of the unit gets flicked and wala, you move to 170wpc into 8ohms, and 270wpc into 4ohms! Of course, class A. You want sweet looking? Try two of these babies side by side! I've written plenty on it; just go to my review on the Asylum. You'll actually see two of my reviews; one was for the unit in stereo, the second is for the twin amps in mono config. I've had some very nice tube pre/amp combos come through (I'm a reviewer with Dagogo.com) to date the Pathos Ones are still my favorite reference - at least for now! :). They are QUITE a bit better in bridged mode than stereo and they do quite well with speakers of a variety of sensitivity, from 87dB-ish range to 95. Note well, however, if you are a person who's seeking "realistic" concert levels, then they are probably not for you unless you'd pair them with very efficient speakers. I listen at moderate levels and they've never even come close to clipping or running out of steam. Put them in close proximity and run one remote; they operate in lockstep.