If the gear guru will indulge me,what is the physical significance of wattage on amps?What,for instance,is the difference between a 15w amp and a 60w amp?I know one is probably louder than the other(if we go by the wattage rating of hi-fi systems),but the doctor is excited about a [u]15[/u] watt amp,so there's got to be something more to it than just loudness.