My professional engineering opinion, having done both amplifier and speaker development, is this is potentially harmful and a serious flaw with the Asgard. The Schiit amps are clearly not designed for good objective performance. And when designers have other goals in mind there are often some serious side effects. NuForce doesn't seem to care the uDac-2 has serious channel balance problems for example. They claim that bad channel balance was necessary for the best sound at the price. The Asgard may have been designed with similarly misguided, or sloppy, priorities.
I hate to say this but your AKGs may already have been damaged and it's just not obvious by listening to them.The material properties of drivers are critical to their performance. For example, when I did speaker development, we had a high-end tweeter dome that was accidentally "dented" in. It was a replaceable dome/voice coil assembly so I took the tweeter apart and carefully popped the "dent" out. The dome looked perfect. But the tweeter then measured completely differently and sounded worse. It had a new peak and a big dip in the response that were not there before the dent. We ordered a new dome/voice coil and it again matched the original measurements.
The manufacture (Seas) told us denting the dome creates concentric weak areas in the material. And at some frequencies it no longer behaves as much like a piston. Some call this "breakup". The force from the voice coil is supposed to move most of the diaphragm as a piston with the outer suspension being the part that's supposed to flex. But when the diaphragm has weak areas, it effectively "breaks up" into a smaller diaphragm within the bigger one. The weak area acts as an unintended suspension.
That was a fabric dome treated with some sort of polymer. The AKG drivers are obviously made out of a different material--I suspect a polyester film like mylar or something similar. My guess is polyester is prone to a similar sort of weakening but I'm not a materials expert so I can't say for sure. But anything that alters the rigidity and flexibility of the diaphragm material *will* change the performance of the headphones. That much you can be sure of.