My understanding is that the larger 1/4" plug that comes with most decent cans has a larger surface area and thus forums a superior connection with the jack.<BR><BR>How much of a difference of sound ...
Sennheiser sells a nice adapter in their online store, at least in the US. It's $4.95 + $5 s/h and has a short cable between the 2 plugs, to reduce physical stress on the port of the sound card.