http://cgi.ebay.com/60mm-Earpa...;hash=item3a6412b0b6

http://cgi.ebay.com/40mm-SONY-...;hash=item43a13d7f72

They arrived, but they're far from being "super thick" as the description read.

I really wonder what the original equipment was like. Any idea?

Super thick I do not know, they are not the foams which did come with the original ones I believe, but for that money!, who cares!!

Now you can foam for the years to come!

Hello everyone, I am new to the forum.

To answer eclipsedave's question: the second of the two listings above are in my opinion good replacement foams. The original replacement foams were the EP-51.

In 1986, I owned the Sony MDR-31s. The MDR-31s were smaller but otherwise identical to the MDR-51s. The original replacement foams of the MDR-31s (EP-31) were thinner than the foams sold by the UK seller of the above listings.

Like yourself, I received the MDR-51s with my D6C without foams. As far as I can remember, and based on the MDR-31s appearance with the original foams, the 40mm foams are an almost exact match.

I still have the old and damaged MDR-31s: I will check if there are any foams left and post a picture of the originals if that helps.      

I found the MDR 31s in their original box complete with the ep-31 original replacement foams. I took a picture of the right earpiece before the foam started to disintegrate. As I thought, they were very similar to the MDR51s replacement foams sold on ebay: (http://cgi.ebay.com/40mm-SONY-MDR-HEADPHONE-EARPHONE-PADS-COVERS-FOAM-X-4-/290467970930?pt=UK_CE_MP3Access_RL&hash=item43a13d7f72) 

Notice the circumferential seam.

Apols for re-opening an ancient thread, but I didn't want to re-invent the wheel... I was searching for MDR-31 headphone covers, and found this thread. 

Plissken: The pics you've posted aren't original Sony foam covers. The covers that originally came with these headphones are actually a dark chocolatey brown sort of colour, and were more of a fitted pocket, than a generic black foam cover - they were also more "velvet" in finish, and not just standard foam. These headphones were the nuts back in the late 80's when Walkmen were all the rage, and the sound quality from these was just a cut above. 

I'm trying to find some really high quality 35mm covers as a result, as the original covers have sadly long since degraded with age. Does anyone know where some really high quality 35mm covers can be sourced? I don't just mean the cheap foam things that you can pick up on Flebay in packs of ten - I mean really decent ones.

I wouldn't mind the faux leather finished pads, like you get on the Sennheiser headphones, but can't find any less than 45mm in size! 

Would appreciate any pointers in the right direction...