Not so. Every DAC has an amplifier. Just like any amplifier, its THD+N is proportional to level. Without level, THD+N is useless.
Now, who else omits that level? The chip companies!
http://www.akm.com/akm/en/product/datasheet1/?partno=AK4490EQ
View attachment 8495
-112 db is 0.0002% that you give me.
What this says is that you have not measured the output of your DAC. Instead, you were giving us chip specs.
AKM does give us that detail later in the datasheet:
View attachment 8496
We see that quite a bit of conditions are stated there with these numbers. Bandwidth for example is limited and that reduces the noise (ultrasonics filtered out).
Actually it can be a big deal. While it is very unlikely that you can better those numbers from AKM, you could have very well made them a lot worse. So much so that you could be creating audible distortions.
How do we analyze the sound? With full spectrum of THD, not dumb numbers. In that regard, ML, Benchmark and you are all presenting improper set of numbers.
That is why you never see me put forward numbers like this.
I show the spectrum which then allows us to use psychoacoustics to determine audibility of distortions.
In summary, the industry is bad. But you are far worse by copy and pasting chip specs and not even bothering to make any real measurements.