I could be wrong. I am not extremely knowledgeable about the making of headphones. The momentum would randomly cut out and come back. The ones I am referring to whether a reincarnation or not were explained to me as having a diode issue and that it was causing the issue. I am 26 and sadly I got those headphones back when I was 18. My memory might already be failing me.
The Momentum is a brand new product.
They're also quite unlike any other headphone Sennheiser has ever produced (in appearance) to my knowledge so I'm not sure what headphone you're thinking of from 8 years ago. Maybe something from a different manufacturer?