I can only add that before I purchased my H2O Signature Mono's I drove up to Henry's (the designer) to audition them with my preamp. His listening room is a finished garage, to me it appeared 2 and a half car, with at least a 15 ft. ceiling... a large area none the less. Anyhow, we hooked up my preamp (First Sound Presence Deluxe Mk II) to the H2o Monoblocks (standard) that Henry had driving his pair of Apogee Scintilla's. The first track played was one off of Patricia Barber's Modern Cool album. Perhaps 3 seconds elapsed before I hit the pause button to ask where were the subwoofers? Needless to say, there were no subs, just the planar ribbon speakers, in an enormous area to fill, in which there was tight, well defined, articulate bass that made you feel as if you were in a movie theater. I asked about the subwoofer because having owned Martin Logan's and hearing many planar, ribbon speakers, I have *never* heard any planar speaker with that level of dynamics nor depth and slam. The rest of the frequency spectrum was just as impressive, but I mention the bass and the room size to give you an idea of the load the amps were pushing into a speaker that dips below a 1 ohm load. After a few hours of playing, I just *had* to touch the top of the case of the monoblock... I was shocked to find it the same temperature as if it had been sitting turned off for hours. The same temperature as any other piece of metal sitting in the room at ambient tempature. Amazing. Equally amazing and shocking to me was the finesse and control in presentation of the music from these amps that had the speakers eminating fluid music that was unforced and natural at levels that just made you smile and shake your head, as everything was crystal clear, and no sense of strain at all... If I didn't mention, these were also the stock/standard monoblocks that I was listening to that sold me. I bought the Signature versions unheard, as if it could get better than what I was hearing, I wanted it.