I'm continuing to enjoy my new Asgard 3, mostly with the Hifiman Sundara. It is still my favorite headphone pairing with this amp. I'm glad this is the case as I pretty much got this amp for it. I'll post some cliff notes I've taken over the last few days below.
I had been considering the Hifiman HE400 to use with the Sundara, but after using the Asgard I've pretty much lost interest in the HE400. This is mainly due to it being what I consider another DAC, with only USB inputs, that happens to have a headphone section. I don't need another DAC
not to mention I'm happy with Asgard 3 + DAC module getting the job done well at around half the price.
Between Modi 3E and the 9028 card, Modi has been boxed up and off to a new owner. I prefer the 9028 card but only slightly. I noticed a little more detail with the Modi 3E but at the expense of being a little dry. Very small difference, to the point where it would be better to consider whether you need a coax input to hook a CD transport up to your DAC. It's funny how things work sometimes. I didn't want to consider the onboard DAC at first...but then here I am liking it more over a standalone unit.
After a while, I'm not as opposed to the HD6XX pairing on the Asgard 3 as I initially was. The 6XX/A3 combo is not as engaging as I've heard on other amps but with a good source I enjoyed using this headphone. It's still not my first choice for an amp, compared to say a Valhalla 2, but for someone with a lot of headphones of varying impedances that tradeoff is probably worth it.
Preamp function seemed fine. The Asgard's slightly warm sound is noticed throughout. It did answer a question that was in the back of my mind, which was whether or not I needed a preamp for HP listening. Didn't do much for me there. Maybe once I get to a speaker setup.
I was surprised with the performance out of the HD800S on the Asgard 3, in a good way. Maybe the Jotunheim or Lyr are a better match for the HD800S but at least I won't have to shill and I can like Asgard as a cheaper option. Jotunheim 2 is still piquing my interest a bit for my Sennheiser headphones, just to see how it stacks up against my HDV 820.