I know this is a way old thread. I just received a pair of the SP3XC They look like they were made yesterday, box and all. The guy that got them from on eBay got them from an estate sale. Looks like they were purchased and never used. These were made betwen 62 and 64 I believe. These have never been burned in so I was pleasntly surprised when I tried them out, I am breaking them in now. Listening to Joe Walsh on the 50 years of the Fender Stratocaster, a television special on the old Paladium TV channel. These things do not sound that bad and are fairly comfortable. I am impressed. I never listened to these back in the day. These are the second version of these cans. The first version had a rather thick straight cord, the "C" version had a coiled cord, the first version had these weird composit ear pads, these have a more conventional pad design. To the guy from the Netherlands that said Koss headphones are just bad, obviously had never listened to any of the premium Koss cans. Enginepartsguy