This receiver centric mania is very strange to say the least. While I fully understand that in many cases it is the best economical alternative and it does usually represent the best alternative for new codecs and formats, to suggest receivers are on par with the acoustical performance of a powerful amp and well implemented pre-amp??
I've done an A/B test, long ago, with a Parasound Halo amp and our Onkyo 797 receiver.
The three people who tried the test could not tell any difference. We even used individual frequencies from an audio test disc aside from music.
Let's not confuse the really cheaper, lower end receivers that have limited power supplies and/or features which may restrict the sound quality they can produce, with some of the midrange receivers or higher that have at least quality components in them (e.g. HTIB 'receivers' vs. a $500 Denon).
I have a Cambridge Audio receiver in our main room at the moment (for its switching features mainly) but it doesn't have a 'direct' mode selection, only stereo or other DSPs (DD, DPL, etc.). Anyone who thinks that is a quality receiver would be correct, for its build quality, but sound quality it wouldn't compare to a separate amp and pre-amp combo solely because of the 'direct' mode to which i refer.
If someone didn't know that was a difference and did a subjective comparison, well then that's only one example of how these rumours of receivers vs. separates gets started, then snowballs.
As long as the audio signal is not engineered in the electronics by going through filters for a design reason, a receiver will play sound equal to an amp, preamp combo.
Any test of a frequency sweep with these equipment pieces should show a flat frequency response across the spectrum (power specific artefacts like clipping excluded). If they don't, you may as well be using tube amps since the electronics are then truly colouring the sound.
