I've also had lots and lots over the years (T1, T1.2, T5p, T5.2, DT770 x4, DT1770, DT1990, DT700, DT880, DT1350, T51, T70p, T90, Amiron, Amiron Wireless) and only once a bad driver. So getting two in a row is really bad luck and not representative of Beyerdynamic quality.
Of course its possible to kill a driver by overloading it. But if you only played through them while on your head, I'd say your ears would have given out first
@Oscarilbo
The DT770/250 is said to be the most balanced version of the DT770 series, but I never heard it. If you're sensitive to bass, avoid the 80Ohm version. That one I do know, and its fun. Different bass from DT700 though, less kick, a bit more emphasis somewhat lower.