For me I listened to both [Anthem AVM90 and Marantz AV10] and it's not really a comparison when it comes to what your ears are hearing, the Anthem just does a better job on sound, I like to focus on sound quality...
The real question, assuming your above-mentioned comparison was level-matched, is whether you would be able to replicate that preference in a controlled listening test.
If yes, then the sound waves actually are detectably different to you, and the difference has a clear preference in favour of the Anthem to you.
If not, then you are suffering confirmation bias, and you don't actually have a preference for the
sound waves of one over the other. Your bias could be due to many influences, but the obvious bias would be knowing that the Anthem has put special emphasis on sound quality...at least in the spec sheet and marketing blurb.
In general, for DAC/preamp combos with good specs and flat frequency responses, it would not be expected for you to even distinguish them in a controlled listening test, never mind have a clear preference.
In your comparison, you would also want to account for the AV10's DAC Filter 1 vs Filter 2. The default, Filter 1, has a slow rolloff and might, barely conceivably, have a just slightly detectable rolloff at the absolute top of the audible treble range. See post #1 in this thread. But even if that were the case for you, one only has to switch to Filter 2 for it to disappear.
Comparing the performance level of the AV10 with the limits of human hearing, it is clear that the AV10 can deliver absolute transparency in audibility. You can't get (audibly) better than that, you can only get worse.
That is why the odds are strongly in favour of your result being confirmation bias. Which is unrelated to the sound waves themselves.
cheers