wingnut: what your "audio experts" tell you MAY be the absolute truth whether or not they actually are "electronic experts!" If you like to listen to really loud, and I mean really loud, music, a low powered amplifier may clip and distort. This causes a large (huge) amount of electrical energy to fall in the audio high frequency range. In most speaker ensembles, the tweeters are NOT designed to take the full rated speaker power. For example, for a speaker that is rated at 400 watts, the tweeters may only be rated at 40 watts. You can verify this by reading reviews from some of the audio review boards.
If your amplifier clips/ distorts, you risk damaging/ destroying your tweeters.
I suppose that one could have too much power, but I suspect that you are more likely to damage your hearing and rattle your house before you hurt anything (that supposes that you have "good" speakers).
Enjoy your 770!!!!! I would be interested in further comments.
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The Rat.