Those who are familiar with the Sony evaporated diamond technology (used in the MDR-D77, MDR-E484 and others) will already know how good these sound. They use a 40mm driver with an evaporated condensed diamond diaphragm, which is just about as incredible as it sounds. It was a technique used by Sony in the late 80s, which involves heating a synthetic gemstone until it evaporates and allowing the vapor to condense onto a diaphragm mould. This results in a very thin diaphragm that is sturdy while still being incredibly light, and is the source of this headphone's excellence. The drivers were taken from a pair of MDR-CD900 shown in the last three photos (available only in Japan) and placed in the MDR-7506 headband. The addition of a new coiled cord (replacing the unwieldy straight cord) and new earpads makes these like new! The 7506 headband folds up, which is an advantage over the original non-folding MDR-CD900 headband. The installation work was done by Abell Audio here in Columbus, Ohio. Again, these are not 7506 drivers, but the far superior MDR-CD900 drivers installed in the 7506 housing. They sound better than the MDR-7506 or MDR-CD900ST.

The MDR-CD900 pictured in the last three photos was discarded except for the drivers. The item for sale is pictured in the first three photos.

If this item does not sell, it will be relisted, but at the same price.