This idea that the Vali scales up is a bunch of non-sense IMO. You're all basically fixing the Vali's faults with even more (nice) colorations.
You know what the problem is? It's not the Modi. The Vali is what's holding the Modi back and not the other way around.
I tried about a half dozen sources with the Vali and the HD-650 and the Vali craps up the sound out of ALL of them. I can't tell any of them apart. In my book attaching a fancy DAC to this thing is like plugging them into an E9. Probably would get similar results when trying to hear their different qualities. You can't. With an O2 or what I already have, it's stupid easy. Why would I want to muck up the sound of a crystal clear DAC with the Vali's muffled noise? I don't.
My guess is that maybe the Gungnir has a massive soundstage, is lean and sort of bright with sparkly treble. Well that would do the trick. I wouldn't want to buy a DAC to de-crapify my amp honestly.
Feel free to proclaim I'm wrong because I don't have $10,000 gear and have bad hearing. People can test this out and see what they find. There is no reason the Vali should sound bad with an ODAC or Modi when using the HD-650.
NOTE: Q701 is pretty amazing on the Vali and didn't change a thing. The HD-650 on it was a complete fail.
I wonder why when I asked a Schiit Tech which amp he would suggest for me to get out of the Magni or the Vali for the Titanium HD Sound Card for the HD 650's the Tech stated "The Vali without a doubt"