@Ash is our resident expert on this IMO. Some years back he sold me a refurbished pair of 250/II's that I was using enjoting less than five minutes ago.

HD250 and HD540 models use the same earpad outer diameter and identical lockrings so the pads are completely interchangeable. Using thickened 540II velvet pads on the HD250 improves the sound to my ears but you partially lose the acoustic seal so sound can move between inside and outside. Having a semi-open design instead of a closed design would render the headphone unusable for certain applications where sound leakage can't be tolerated.

Hi there, I just received a pair of them last week and they were pretty terrible (unfortunately one can't return them after use etc). 

Their profile is different from the originals (shallower), the pleather kind of squeaks when one rubs them and resulting sound I'd imagine bearing similarities to that of using a seashell! Essentially they were really yucky!

So I've ended up hunting down full headphones sets that have earpads in good condition (eg >32mm pleather top - base of fixture ring). It's nearly as difficult as finding the full velour versions pads for the HD540ii's (Ps thanks Ash for your previous advice on that model).

 The soft cushioning and slack pleather of the originals do so so much to seal off and deliver their designed sound.

I think the HD520ii use a similar earpad however this is just from looking rather than actually fitting.

Best of luck!

Alex

HD540 Reference II was the most futureproof of all the vintage Sennheisers because of the earpads. There was a certain type of 540II earpad that was totally black velvet; it had no pleather backing with the white fabric underneath. The fully velvet were the best due to their ease of stitching up and their higher durability. They also gave a thicker stitched earpad (less foam compression) and one that was all black. They could be carefully cut open around the inner diameter, foam removed, earpad skin turned inside-out to separate from attachment ring then the whole fabric could be washed in warm soapy water or alcoholic gel. I got a very good finish with them. Wonderful headphone for about £200.

If I cannot replace the cable the ‘phones are of no use to me.  The pads are in good condition 

Les

HD250, HD540 and HD560 models all use the same plug type. Source a model with the same OFC cable if you can. More flexible and physically less microphonic than the earlier steel-litz type. One reason I stopped restoring them was because parts became so difficult to source. Even less incentive to buy vintage Senns from Europe now due to Customs and VAT charges.

Really thought I might have to bin both pairs, which have been quite adequate for my use to date. I made the mistake of letting my grandsons use the ‘phones and they did not take the care in use that they should have, hence the damaged cables. Still, if I can wrest more use from them now that’s a good thing and saves the cost of sourcing new phones.

Best Regards

Les

If you are or you know someone who's a dab hand a soldering then the Mogami 2893 copper cable has been cited by many as an alternative if you have no luck.

Alex

Both sets are now back up and running and will hopefully last a few more years!

Les