Hey everyone. This is my first post here, and I was just wondering if I should consider sending back my DT 1990 Pros and purchase a different pair. I really love them, but they have a noticeable noise floor that none of my other headphones (6xx, 4xx, k7xx) have. I am using an emotiva a100 with a jds labs ol dac. I have looked into ground isolating, but that is evidently not the problem as the a100's plug is only two-pronged. Does anybody know about this combination? The hum isn't too bad, but for almost $600, I'd expect a better noise floor than my other three headphones, which I spent less on combined. Thanks!!