This is so misunderstood, probably the most misunderstood concept of all in hifi.

Let's start with the simple parts:

Power and watts per channel have NOTHING to do with volume.

Get that?  Worth repeating?

Power and watts per channel have NOTHING to do with volume.

How about this to follow:

100 watts is not twice as much as 50 watts

Twice 10 watts is 100 watts, twice 50 watts is 2500 watts

It follows from this that the difference between say 50 watts and 70 watts is very very little, even if people did know what it meant!

Watts mean very little to most people in practice, and yet it is usually the one specification they check, because it is the one number they have heard of.

Watts mean a lot to manufacturers, as it is an easy way to say (imply) that their more expensive amplifiers are better than their cheaper ones

Don't get me wrong, the higher powered amplifiers are often better, but not solely due to the power.

And to compare two different makes of amplifiers by power makes no sense at all!

Anyway that's not the problem, if power means nothing how do we choose?

Next part to follow!!