House Amperage vs Stereo Amperage

Sean, I totally agree with your comments. If you read carefully the first sentence of my response that is exactly what I said and thats why I think the whole discussion concerning 30A draw from the mains supply is a red herring !
In my example of 30A OUTPUT current, equating to 1500W - in my book this is big whether peak to peak or rms unless you have some very power hungry speakers!

However Power output is directly related to power input.
You can never output more power than the mains can supply, and is actually usually less because of ineffiencies of amplfier designs. Amplifiers (and mains supply) can on an instaneous basis supply more than rated current and manufacturers use this quoting music power, pk-pk etc for marketing purposes.
No sane manufacturer is going to commercial a domestic amplifier that needs more than 15A of continuous current from the mains.

sean...About circuit breakers...when a tree next to my house was struck by lightning almost every fuse in the house blew, but not a single breaker opened. (Give me fuses any day).

About rail voltage sag...if the audio signal peaks at 35 volts this can be output by a 70 volt rail voltage with the transistor conducting 50 percent, or by a 60 volt rail voltage and the transistor conducting 58 percent. Because the rail voltages are heavily filtered in the power supply (and sometimes regulated) the "sag" (as the name suggests) will be at very low frequency, which any feedback loop can easily follow.

Not sure if this is true but I read that if you wind the power cord or extension cord in a circle, say 6-7 times, when lightning strikes, the cord will melt like a fuse.
No charge for that one :)