The DAC cannot be overlooked. It is such an integral part of the chain. The better the amps and headphones, the more important the DAC becomes. My first 2 decent DACs were both R2R or NOS DACs. I had the Metrum Musette and then the Vinshine R2R REF. I liked both very much, but from a synergy standpoint my current DAC is providing the best SQ my system has yet to realize. I am not sure how much of this is amp and headphone related. My amps are far superior to what I had at the time, as are the headphones I am currently using. Plus, I have added Roon Labs and a USBe Perfect providing much better jitter reduction and clocking. I definitely am ready for the next DAC for my system, I am just not sure what it will be. I have been leaning towards the Exogal Comet, PS Audio Perfectwave MK2, or a Lampi Amber 3. Really depends on my budget when and if I can move my TEAC. That being said, I am listening to my Auteur through my Spring 1 tonight with my UD-505 sending the 1s and 0s and things sound just about perfect. I thought I would only use my Auteur on my Mainline, but I prefer the Spring 1. Bass weight, speed and uniformity are off the charts. As you state, the "musical neutrality" of the Auteur lends itself to a lot of flexibility. I am still in awe of the Auteur. I have put about 25 hrs on it without any forced burn in, and I continue to be amazed. The sound is resolute, without being shouty. The midrange is open and honest. Treble has the exact amount of push and pull. As if a parachute is opening and I can feel myself floating to the ground. Mostly, the Auteur sounds like music. The best quality and attribute I can think of for a transducer playing music. Which leads me back to a DAC. I would love to get an R2R DAC. However, I don't want just any... Perhaps the Merason DAC1, or the Hibiki SDS Discrete, or a nice tube DAC will be next. What I don't want is to get a mediocre R2R that only gets me part of the way there and leaves me less happy than my capable TEAC UD-505. Honestly, for the money I have yet to hear a better DAC than the TEAC. Its sense of pacing and rhythm is spot on. And its flexibility with voltage makes it a home run. Choices choices choices... At least I have an Auteur to help me discern the differences and lead me down the right path.