Last week, I picked up a new DAC, and I now feel compelled to modify the above statement, because this new DAC changes a lot about what I feel like the Bakoon contributes to my system.
With the Bartok (as opposed to the DAVE, which it's replacing), the AMP-R13 + Susvara sounds just really, so right to me at the moment. It's extra smooth, very relaxed, warmer, and exudes (extrudes?) more depth and more defined images. The sound reminds me of the HE1000v2, if you see what I mean. It also sounds remarkably pleasing at low-to-medium volumes. I'm totally happy with this amp/headphone combo now. About 90% of my listening with the Bartok thus far has been with the Bakoon + Susvara.
Whereas on the DAVE, the R13 + Susvara sounded a little lacking in warmth and bass quantity, a little flat, and somewhat compressed. In a word, kind of boring. But I can't even claim to be able to generalize this to apply to any DAVE with the R13 + Susvara, just my own DAVE setup, since there are like 10^14 ways of setting of the source going into the DAVE, all of which matter (In contrast, with the Bartok, you just connect the network cable and you're pretty much golden).
The Utopia, which I wrote about dismissively above, also sounds really good with the Bakoon now. And the TC, which I previously ranked first, now comes in third. My DAVE gave it a denser, more forward sound out of the Bakoon, which worked better with that headphone.
Key takeaway: When considering amps, the DAC matters. To the point that it's almost misleading or even harmful to blithely give an opinion of an amp without also qualifying those opinions with the DAC that it's connected to. No big revelation, sure, but presumably I'm not the only one who needs an occasional reminder about it...