No KMan1211,
I made that mistake, posting as Sennheiser, and said the HD 660 S pads were different. This was because my first experience with the HD 660 S was at Sennheiser's headquarters and flagship store, and apparently the pads on that model was more used than I had anticipated (it was different than the new-old-stock HD 650 + Apogee Groove I had received from Sennheiser in order to be familiar with a popular model), but I redacted the comment years ago. The HD 660 S that I received later, after the more squared-off earcup/yolks design, had the same pads as the HD 650.