All of these replies are excellent, and I thank you all for sharing your knowledge. It appears to me that--yes, more power can give you more dynamic headroom; a sense of ease during a John Coltrane solo hitting the highest octaves at high volumes--or Paul chambers hitting the lowest octaves in terms of articulation of tight bass--but, there are probably more important attributes of the amplifier that relate to delivery of that power, and a clean delivery results in impoved micro- and macro-dynamics. So a 100W amp can be much more articulate, dynamic, and have better imaging ability than a 200W amp. The point is that one should not make a decision based on amp power but on musical presentation--which applies to all audio equipment. I just wish I could get a handle on that nebulous amp attribute that allows a 100W amp to shine over a 200W amp, unless that ability relates to a clean power output alone.
Does the power of an amplifier really matter?
Excuse my ignorance, but I am trying to understand the meaning of amplifier power. A doubling of amplifier output power results in a 3dB increase in sound-pressure level. So, if I listen to my stereo at a volume of say, 70 dB, what is the difference in a 100W amp vs. 250 W amp? If I listen at 70 dB, is more power delivered to the speakers with a 250W amp vs. 100W amp (resulting in better driver control)? I am not sure that is the case. Is it that a higher powered amp delivers a given amount of power more cleanly? Not sure if that is true as well. Can anyone educate me on this fundamental property of amplifiers?