I have a friend who had the adi-2 pro, and recommended me the adi-2 dac as he thought it would suit me better and its a perfect fit.Thanks @Tsukuyomi
Sounds reasonable. I admit that the TH900 could also be a bit lighter for a better feel when wearing. And the headband is not easy replaceable.
I see you have also a Beyerdynamic DT1990 PRO, there the headband and overall wearing comfort is better solved in my opinion. Nevertheless i love TH-900.
RME, nice German brand, mostly known for professional audio equipment, also they do serious measurement equipment. The ADI-2 DAC i've never demoed.I will try when i can get my hands on one.
I wasnt able to test the fostex th900mk2 with the rme at the time because i sold both them and the violectric to pay for it and other expenses. That being said, ive tested the dt1990 and fostex th610 on the adi-2 and its great. I find fostex takes nicely to a clean dac and amp. Because fostex cans have their own sound. Deep and heavy bass, not as deep as audeze but, different headphone architectures.