ChrisJ, actually I don't think this is trying to pick a fight at all.
I guess my poorly made point is that the application notes are a "minimum" way to get a DAC working. Calling it a "reference design" was perhaps a throwback to the way companies like NVidia do it. They release a video card that's the "reference" and then all their partners release products that either meet the minimum reference or more often have extra speed, features, etc.
So if you think of these various companies buying the chips from Burr Brown, Cirrus Logic, Sabre, etc... and then putting their engineers to work on "how can we make these things sound as good as we can and sell it at a certain price point" I would *expect* them to come up with different implementation using these chips. But as someone else said, maybe we looking at the difference between what a piece of test equipment can recognize, compared to our ears.
To pick on NAD for a moment, I can't imagine their engineers going to management and saying hey we have this great idea. We are going to build a new DAC and we're going to use PWM and its going to be awesome because we're recognized for some pretty awesome equipment. Oh and by the way it will sound just like a $500 Emotiva. Hard to picture. And yet based on Gary's testing its what we got.
But, we also can't downplay that the NAD M51 is probably well made, and looks good with their M50 player, M52 data server, M3 amplifier, etc. I had an opportunity the other day to see a Woo WA6 amplifier for the first time and my reaction was "damn that is a sexy looking amp". And that reaction had nothing to do with the technical specifications.
Edited by ellemir - 1/4/14 at 10:53am