Alright, duh, I tried swapping out the pads of the DT770's with the HD250II's, and...it worked! Sweet! A little loose (I have to hold them in place when taking them on and off), but...sweet! I am in heaven! I love this forum! Thanks guys!
Not sure if it's changed the sound yet, if so, not much...(listens)...sounds as smooth as it did before...(listens)...the bass is still there...maybe the littlest of bits rolled off on top, but could be my imagination, it's _that_ minute...yes, I think everything is going to be fine...I'll have to find some nice phat techno with some raw sawtooth waves...I wouldn't want to travel with them this way, but...I'll come up with something (maybe put some cloth on the old ones and put them back).
FYI -- they hold on to the headphone differently, which is why they won't stay in. The Beyer's hold on by the outer edge, the Sennheiser's hold on quite a bit more closely in...do all Sennheiser's pads hold on the same way? Maybe I should just get the cloth pads for one of the higher up Sennheiser models?
Also, be careful -- at one point, I almost took the driver out of the cup instead of the pad off the driver/cup assembly...
Edit: Highs are not rolled off at all.