Hmmm interesting that you find the Arya to rock with the RU6 @213mw while I find the R01 @430mw to lack just that tiny little bit of oomph on the Arya
.None of this surprises me, although I find rationalizations and evaluations based solely on statistics and measurements to be somewhat limited. Still keep in mind that :
1. this is the Stealth magnets Arya, which is a lot easier to drive than the previous 2 iterations. The RU6 drives it effortlessly with a lot of headroom left, and without showing the slightest sign of straining...
2. I am using a Norne Audio Silvergarde 4 8 wire to drive my Aryas, and that this 8-wire version is a beast of a headphone cable which is capable of unlocking details, technicalities, and levels of performance in *any* headphones that the usual stock cables are often incapable of matching, however hard they try...
3. I have personally never heard the R01 in my own system and with my gear, and therefore I cannot speak to how it might compare favorably or not with the RU6 in my system. In that sense, if this is merely an experience of "ignorance is bliss," then so be it, since I am not inclined to exchange this kind of bliss with any other kind I know nothing about yet, until I concretely know better.
4. This is about the RU6, a tiny $250 dongle, and its performance, as compared to other rigs worth more than 20 x its value, hence a small "miracle" when judged in relationship to the performance it can work up as compared to all the 'big boys.' There would be nothing exceptionally interesting, or worth being excited about if this were the performance of another rig that was worth say 5k or more.
On the other hand, I do have desktop rigs, such as an Yggy A2 with a Pathos InPol Ear, and a Sonnet Audio Morpheus with a Niimbus US4, which I routinely use with such Headphones as the Susvara, the LCD-5, and the Abyss 1266 TC, and they do provide legitimate templates of audio goodness against which I might compare the performance of the RU6/Arya Stealth magnets pairing. It is in the light of such comparisons that I find the RU6/Arya Stealth magnets to Rock my world, without necessarily implying that the RU6 exactly matches those other big boy rigs in performance, and even if I have not had the luck of listening to the R0!, which I would like to do, when/if I get the chance.
In the meantime, I think your mileage may legitimately vary, depending on how your R01 sounds within the chains in which it is deployed at your end. Speaking of chains, I think they do make a significant impact on the performance of their individual components, a fact which renders an evaluation of any individual component unreliable and suspect, when it is done as if they're performing outside a specific chain. There is also the matter of your personal tastes and preferences, which I have no expertise to assess.
With that said, when I say the Arya and RU6 pairing rocks to my ears as opposed or compared to the performance of other chains I am familiar with, I do not feel I am unduly exaggerating any aspect of my experience, as this pairing indeed rocks my ears. There is no denying that. I can't stop listening to the RU6 paired with either the Arya Stealth Magnets or the LCD-5. It is as simple as that. Since the RU6 arrived, I have been ignoring both my Susvara and the 1266 TC because I think they're, first, too hard to drive to make any sense trying to pair them with the RU6. On the other hand, I have been enjoying the RU6 + Arya/LCD-5 pairings so much that I have not even once missed listening to either the Susvara or the 1266 TC, although I remain aware of what both these cans are capable of, which is a lot. The important thing is that there is nothing in my listening to the RU6 Arya or LCD-5 pairings to convince me that my enjoyment is illegitimate or illusory. I am just having a great time with them, and I feel it is a bit disingenuous to spoil or shortchange that enjoyment with futile speculations about what other "better" or "lesser" chains might produce.
Of course, I do respect the integrity of the experience you report with the R01, which you find to be somewhat subpar, sadly. I wish i could tell you why, which I can't since I am not familiar with the R01 itself or the chain in which it is deployed at your end.
I do not find it entirely constructive or helpful to allow that piece of news to spoil my enjoyment of what i have in hand at the moment, especially if I do not know what I would think, were I to audition the R01 in my own system... i am also trying to wean myself off DAPs at the moment (I no longer listen to either my A & K Kann, or Kann Cube, which are both in excellent working order, but that is an entirely different kettle of fish, I suppose)
I have no expertise regarding how to make the R01 work more to your tastes, since I have no clue what your preferences are, and have never owned the R01. Maybe one day I shall cross paths with the R01 and either find it to be a little on the "meh" side, as you do now, or get my mind blown to smithereens by it, in spite of my current attitude regarding DAPs... We'll have to wait and see
I see that my rant has been entirely too lengthy, maybe much more than I would have ideally liked. This probably has nothing to do with your comment, which may have just caught me at a time when I am feeling too loose-tongued and more longwinded than normal.