I just noticed a couple new things on the 7900 page. First, there's a manual now. Second, there's a write-up under About/Gallery that is new. It gives a pretty reasonable explanation of when a monster of an amp like the 7900 might actually be needed (which is, truthfully, rarely). There's also a fun bit in there that explains why they don't list a 4-ohm rating in the specs. It appears that each channel individually will do around 450 watts at 4 ohms, but if all seven channels were to do that the current draw from two 15A circuits would exceed what those circuit breakers are rated to allow (and very possibly what the associated wires are sized for, for that matter). Here in the midst of a hectic afternoon at work (which will be followed by a hectic weekend and a hectic Monday, by the looks of things), that particular problem with getting the amp rated at 4 ohms gave me a chuckle.