How do I equate those db figures with the actual wattage that the amps are producing?
Peter, that is the very question I have been begging for an answer to. Your experience is basically what I was trying to explain. With a real (or closer to real) 125 watts you system works cleanly because you get those watts without distortion. With BS watts, as on most AVRs, you only get a fraction of those watts cleanly, and you are capped at 90 db.
But how you read a spec sheet to know which amp section will give you clean watts, I can't get an answer to. Too many dismiss the question with "all modern well designed amps sound exactly the same." Yet, in Onkyo's line a mode increase by one add 10 watts, but doubles the high current capability from 36 to 72A. That tells me the amp section of the more expensive model has some gizmo (tech term) that allows it to fuel more of the 140 promised watts before distorting the sound.
But...I have been told that is not a key indicator, and that figure is damn hard to find on most amps, so it is of limited value. All this brings me back to the dirty place - I must put some faith in the professional reviews. Few of us have a Denon and a B&K and an Onkyo to A/B test. Hopefully they give us a grain of truth to work with.
Otherwise, I just have to trust Denon, because I have been impressed with every listen for 10 years, and I can't say that about any other product I own - well, the PS3 is damn impressive too, it does everything but prepare diner.
