It's funny that your impressions on the Gungnir vs the M51 echo mine considering the exchange we had in another thread. < note the wink.
The MJ is a fine amp for the HD800. These components are not inherently abrasive imo. People that have tagged the MJ as such should look to components upstream to isolate the source if this presents as an issue in their system. The "dogmatically vigilant" term coined by purrin is incredibly apt. It was also commented very early in the thread that these MJ impressions likely hinged on the quality/signature of the DAC. This seems to have been forgotten.
The Gugnir is a good DAC and is a significant improvement over the Bifrost. It matches very well with the ubiquitous LCD-2. Look elsewhere if you want refinement deserving of the HD800, HE-6, LCD-3 etc.
Glad you're liking the M51, I think you got a great deal on it. I still feel it's a poorest value considering the MSRP in the U.S.
I will disagree with you on the MJ not being abrasive to a point. As stated MJ makes other amps sound slow, it's extremely transparent
and isn't a laid back amp. Mjolnir is overly aggressive aka "abrasive".
Although I think in context of people generally thinking the HD800 would be fatiguing, you're right. It's not abrasive in that nature.
I think with the HD800 source plays the most important factor. Seeing as the Gungnir is perfectly adequate, anything more
is just in pursuit of those last bit of extra details, that squeeze of resolution.
Whether we want to sit and compare the Gungnir to the M51, compared to the PWD, compared to the Invicta, to Cantata, and all the way up.
I think it should be acknowledged that what Schiit is offering in the mid-tier bracket is endgame.
And the rest is agonizing over that last 10-15% and I'm being gracious.