D'oh. I've had mine for a couple weeks but I haven't had a chance to test them out until tonight. Sure enough mine has a rattle in the left ear.
Otherwise so far I'm impressed by the sound. They have pretty much ruined all my other headphones, they sound terrible in comparison. I'm a little worried about the elastic support, seems like it will be the first thing to go on them, hopefully it won't be an issue. If I can just get the rattle sorted out I think I'll be pretty happy.
gradypAKG considers the rattle to be a QC fault, so just get them replaced.
The elastic will gradually go. Like the ear cushions, though, replacing them isn't difficult. You can get exact replacements from AKG, if you want, but the synthetic stretch bands you'll find in the grocery store, near the combs and brushes, will work perfectly fine.
Here is a doc with an exploded view:
http://www.theshopsouthdade.com/manuals/k601_k701439d5815555d1.pdf
Otherwise so far I'm impressed by the sound. They have pretty much ruined all my other headphones, they sound terrible in comparison. I'm a little worried about the elastic support, seems like it will be the first thing to go on them, hopefully it won't be an issue. If I can just get the rattle sorted out I think I'll be pretty happy.