As some of you may remember, it is my considered view that good amplifiers do not have a sonic signature. Howevr, as you may also remember, that is only true if certain conditions are met. One of them is that the amplifier must have enough power to avoid clipping on dynamic peaks. The next question then obviously becomes whether this is an issue in real life conditions or not.
Ever since moving to a bigger house with a considerably larger listening room, and replacing my old Quad esl 57's with the modern but far less sensitive Quad 2805's I have had the nagging feeling that my old 2x45 watt Quad 303 power amplifier was stressed in louder passages. That suspicion was reinforced when I read about Alan Shaw's demo of the 2x500 watt that was occasionally drawn on peaks by the not even particularly insensitive Harbeth 40.1's as measured during a demo in Hilversum in the Netherlands. It made me think.
So last summer I could buy a completely refurbished 2x140 watt Quad 606-2 (i.e. essentially the same amplifier as the later 707, 909 and QSP) for only 350 euro. And indeed: playing not very dynamic music at moderate levels there was abolutely no difference with the old Q303. But turning up the wick playing large scale dynamic music changed all this. The sound remained clean and the dynamics were far more life like.
So the lesson for me is that watts are indeed watts, but that if you are playing dynamic music in a large roon on insensitive speakers, you had better have many of them. This is all the more so since sound levels are measured on a more or less logarithmic scale: a bit more sound demands a lot more power. I may have to start saving for a set of Quad monoblocs. The reassuring lesson for others is that if you are listening to relatively sensitive speakers in a typical UK living room you do not need too many watts, and they will be cheaply available.