We Know that Sennheiser HD518/558/598 uses same driver but I got Sennheiser HD598 few days ago from German ebay,- purchased for very low price because left driver was damaged and I thought I could use my beloved Hd558 left driver.
However I discovered slight differences, see the attached photos:
I don't know if sound characteristic has been changed. anyway it is interesting information... if anyone can illuminate this issue I would be happy. Now I am using old left and new right driver, but they pair each other very well. :)
HD558 driver purchased from Amazon.com manufacture date 05.11.2010 driver's part number: 93481B
New HD598 driver purchased from ebay.de manufacture date 16.02.2012 part number: 528480
I tore down damaged left driver also
Edited by Lumos - 8/2/13 at 10:17am