"High Current"

The amplifier design determines the maximum voltage that it can put out. The load (speaker) impedance, 8 ohms, 4 ohms etc. determines how much current will flow if this voltage is output. That is, if the amplifier can deliver that much current. It would be possible to design an amplifier which did not put out a high voltage, but could maintain that voltage despite a low impedance load which requires a lot of current. The power rating of the amp specifies that it applies at a particular load impedance. If a lower impedance speaker is connected, more power will be delivered.

Sean...This issue of measuring power "at" clipping is new to me. I usually see specs quoted at some specified level of distortion (presumably an acceptable level). But isn't it true that distortion typically begins to increase abruptly just before clipping, and the manufacturer takes the power value just before this happens? I suggest that power measurements at the two points will differ only slightly.

As an aside, how do you deal with an amp that doesn't clip, because it has clip limiting. In that case I think you will just see increasing distortion as the signal peaks are rounded off.

Sean...To achieve the "doubling down" at clipping which you describe requires a substantial increase in the power supply cost. It is not a characteristic that is particularly useful in the home audio situation, where amps are not driven to clipping. (Pro sound is a different situation). While you are technically correct, I think that the law of diminishing returns comes into play here.

Again from my military electronics experience...when I went to work in 1961 "built to mil specs" really meant "overdesigned", and the poor taxpayer paid the bill. Recently we have built even the most complex military systems (such as a Fire Control System to prepare and lauch 24 ICBM) by assembling Commercial Off The Shelf (COTS) hardware. That old custom designed stuff was interesting work for the engineers, but common sense prevails.

Sean...To put it briefly...we don't operate our amps at clipping. What we care about is distortion-free power, and that's what is usually quoted.

BEAR this in mind :-)

Sean...How could I have missed your point? All those beautiful audiophile words..Clean power, refined musical and natural, lack of smearing strain and ringing, harmonic structure, yada yada,yada. I just don't agree with all your conclusions.