I just wanted to jump back in here with an update on my experience with the DT880 Premium 250 Ohm. I have had them for a little over 2 weeks now. I have used them almost every night since. I must have 40 hours on them by now. Out of the box, there was some additional treble energy in the 6kHz to 10kHz region. If I had to take a guess by ear, I would say right around the following level of additional energy.
6kHz +1
7Khz +1
8kHz + 2
9kHz +1.5
10kHz +1
However, I honestly did not find it fatiguing at all. It just offered additional detail retrieval, and allowed the headphones to expose more in the music. After probably 40 hours of use now, the headphones sound even better than they did out of the box. At around 30-35 hours of use. I really noticed a great improvement to the bass. It became tighter, deeper, and more defined. It is definitely capable of reaching down low when the music or a video game calls for it. Out of the box, the mids were gorgeous, although just slightly recessed. It appeared as though the mids were just slightly behind the bass and treble while listening. After 35 hours or so of use, the presentation ended up moving forward. Everything is just so balanced now. I will say right now that the mids on this headphone are the best I have heard thus far at the 250 dollar price level. The sound is so musical, and without any fatigue at all. Now, regarding the treble. That additional treble in the 6-10khz region has just seemed to have magically disappeared almost completely now as well. All I hear left is perhaps a +1 additional splash of energy at right around 8kHz. It is nice and airy, without any fatigue. I just find this to be an awesomely balanced sounding headphone.
Of course, we all hear things differently, but I am amazed that I have heard people claim these headphones have ear piercing treble. I just don't agree with that at all. In my experience, the DT770 Pro 250 Ohm, now that had fatiguing treble, as well as bass. I did not like those headphones at all. I am currently running my M-Stage HPA-2 (Non USB version) as an amp with the stock OPA2134 opamp. For a DAC, I have been switching between my Aune T1 MK3 (latest version) with Genalex Gold Lion E88CC Gold Pin Tube, and my HT OMEGA Claro Plus sound card. I have an LME49860NA I am going to pop in the M-Stage in the next couple days which will certainly offer an improvement as well. At this point, I think the DT880 Premium 250 Ohm is a great pair of headphones.