Umm, okay..
I'm really lost right now, I can't choose..
Based upon your comments before you edited,you seem stuck on the DT990s 250 ohms. To repeat myself,
You will hear your keyboard clacking
I do not know if the Soundblaster Z will work well with it or not. Perhaps another member can assist you?
I prefer external amps and DACs. The Magni 3 will drive the DT990s easily,as well as all the other headphones weve talked about above.
Will you like the way it sounds? Only you can decide that.