Naw, Rick; no claim that it's "all in our heads". That's part of of it, of course, but the other part is not controlling the variables adequately, such as is done in a proper blind listening test. The most significant variable usually being the necessity to match the volume levels to about 0.1dB, which can't be done by ear. When the new unit is played slightly louder these observations about stronger bass, overall clearer sound, bigger sound stage, etc, none of which can be accomplished by any amplifier at the same sound level, appear. So you("you" meaning all of us)can't simply "Just trust your ears", the slogan so loved by audio salesmen making claims which have no factual support.
In controlling the variables you have to test at equal standards across the board. For example, if power is a potential factor in the experiment, test at a low standard SPL so that power is removed as a factor before concluding on differences in sound between amp sections of equipment.
Obviously at high enough SPL the Denon receiver will fail in comparison to a separate amp in reproducing sound which has a more substantial power system.
More than once i've seen the lights dim on my Onkyo when i drive the 5 speaker system too loudly.
