I understand what you are saying. But this discussion is going to go around in circles with no resolution, because you do not seem to be understanding why exactly
@SIY and others are refusing to "answer your questions."
Maybe this will help clarify things: If you heard a difference between those two DACs, then that's what you heard - that's the perceptual experience you had. No one can prove you didn't have that experience - and despite what it might seem like, no one is actually questioning that you had that experience.
But you're not just saying you had that experience. You are
using your experience as evidence in support of the claim that "measurements are not final," and that "in audio gear there is something beyond measured sinad, linearity or dynamics ... Maybe measurements are not all you need to evaluate quality you are looking for."
That's where the difficulty is. Your experience is real, but by definition it's only real
for you. That does not make the conclusion you draw from your experience
true. So your experience is not false - it's just
meaningless to anyone else here. It's meaningless when it comes to supporting a claim that the measurements taken at this site are somehow inadequate for establishing the
objective fidelity of equipment.
To put it another way, there are many reasons you could hear a difference. A few (but not all) possible reasons include:
- There is some actual difference between the DACs that does indeed create different audio output that, if we tested it properly, would be reliably detectable by most people;
- The conditions in which you listened had some psychoacoustic impact on you that made you unconsciously focus on certain aspects of the sound when you listened to one DAC and other aspects of the sound when you listened to another, which created an impression in your mind that they sounded different, and that impression shaped your subsequent listening impressions;
- A small difference in output voltage or some other electrical variation created a volume level mismatch when you compared the two DACs, resulting in a different sonic perception that you did not experience as a volume difference but rather as a difference in soundstage etc..
The key point is that a wealth of human knowledge, documented in scientific literature across a number of fields, tells us that reason #1 is the
least likely possibility, regardless of how you individually experienced the situation. At the very least, the established science tells us that proper double-blind testing must be done in order to rule out factors other than #1 before we can seriously consider the possibility that #1 might be the proper explanation for your experience.
Now of course, most of us don't have the equipment, time, resources, or patience to conduct proper blind testing. Fair enough - life is short, music is meant to be enjoyed, and so if you like one DAC better than the other, of course you should keep it. Be aware, though, that one of the many problems with your claim here is that it assumes that if you were to conduct this comparison again in a month, or a year, or five years, you would have the same experience and come to the same conclusion. I know it doesn't seem to you like your perception would ever change, but don't bet on it. You might be surprised at how often perceived "night and day" sonic differences simply disappear at a later date (because those differences were not objectively true to begin with).
Regardless, once you've decided to keep your preferred DAC and you are happily enjoying your music, if you then come here and say your experience shows that there's some mysterious, unexplored aspect of sound quality not captured by the suite of measurements that Amir runs here, you're making a claim without evidence, and no one is going to "answer your questions" in the way you are trying to get them to do. Instead, they are going to ask
you questions because it is already well-known and well-understood that your argument has serious flaws which must be addressed or acknowledged before anyone is going to entertain your point.
Finally, one important side note: Even if there is some actual, measurable difference between the two DACs that has a reasonable chance of making them actually sound different, it is important to note that
different does not automatically equal
better. This is what we call euphonic distortion: a piece of equipment has
lower fidelity to the original source, but to some folks it can sound
more pleasing because the distortion it adds produces a pleasant effect. For example, high 2nd-order harmonic distortion adds new tones at double the frequency of the original tone. In some cases this can be perceived as a slight extra "ambience," or a "fuller soundstage," or "warmer and less clinical" in sound. That's fine - live and let live, enjoy what you like. But the fact that
personal taste varies from person to person is precisely why we cannot use that personal taste to argue for new rules about defining the performance of audio gear: your taste might not match mine. That's why fidelity, and measurements of fidelity, are essential: even if you find that you prefer equipment that deviates from maximum fidelity in some way, it is only through measurements that you will be able to find that equipment - just like if I am pleased by the highest possible fidelity, it is only through measurement that I will be able to avoid that same equipment.
The reason I have left this point until the end is that while we could say that your preferred DAC might sound pleasing to you because it deviates from maximum fidelity in some way, that claim, tempting as it might be, would also be an unsupported and suspect claim if the measurements did not show any sign of potentially audible performance problems.
Hope this helps.