That sucks. Fortunately (thus far), I have not experienced this behavior (yet). We shall see as time goes. Other than that, I thought those headphones were fantastic, and my amp/dac (Matric M Stage HPA-2) is only a modest one. But I am really quite pleased with the clarity of the vocals. A big step up over the HE-500 and D5000.
Even before connecting an amp to them, i thought the headphones sounded awesome!!! And then a bass song came on and rattle kick rattle rattle rattle. And with the amp it was way worse. I completely turned the volume down to get rid of it. It's a first of a kind experience.