Reddit mentions of SENNHEISER Samtpolster Fuer PC350 Headste 2Stueck

This is a link to what I ordered but they are listed as unavailable now.

Here is the band pad I got recently. It's not a 100% perfect fit but works fine.

Sticking to the Sennheiser store is probably the best bet for finding OEM pads that work. They're about twice as expensive as third party stuff though.

Yes, I felt the same way and found that the pads are the culprit (see my writeup on it here:
https://www.massdrop.com/buy/massdrop-x-sennheiser-pc37x-gaming-headset/talk/1626716)

With the 595 pads, they sound just like the HD 598. Pads here:

https://www.amazon.com/dp/B002STGF6O


or a little cheaper here from the same seller:

https://www.ebay.com/itm/192435559969

I'm late to the game, but just in case you haven't bought yet, or someone else reads this:

searching for "hd598 alcantara" or something like that returns zero results on alibaba. It seems to only search titles maybe? Anyway, just search for hd598 ear pads and then manually look at each listing. Alcantara will be in the text of some of the listings (not the headline).

I'm buying some now, I guess I'll find out if they're any good in ~2 weeks.

edit: I ordered from aliexpress, not alibaba, just to be clear.

edit 2: Here are the OEMs on Amazon for $35. Personally I'm giving the $8 Aliexpress ones a try.
https://www.amazon.com/Genuine-Replacement-Cushions-SENNHEISER-Headphones/dp/B002STGF6O/ref=pd_lpo_vtph_23_tr_t_2?_encoding=UTF8&psc=1&refRID=214RRGQ3Q2S8HNSZPTKS

Are the cups (the plastic housing for the drivers) actually falling apart, or are you referring to the earpads? Because you can buy replacement earpads for much cheaper than an entire new headphone.