I'll start a potential fire here. There are quite a few folks here who maintain that there really shouldn't be that much difference among receivers. I agree with that to a point. Once you get to a certain price/quality level, that's probably true. But I used to have a $300 Sony and upgraded to a $650 Marantz, and the difference was astonishing. The Sony always seemed like it was struggling. On the occasions when my Marantz isn't errupting into a fireball, there's nothing but headroom and pure, clean sound.
It sounds like you're probably pushing the Sony too hard. Why, I don't know. I'm sure someone else will be along shortly with a more coherent explanation/recommendation.
