Hi, thank you for your posts.
First of all, I'd like to point out that there is the rattle only in bass. When I play classical or even Metalica (Load/Reload plenty of bass) it is perfect.
I do not know how loud K1K can play. WA5 is pretty powerfull amp, so I do not know - maybe I reach the limit.
Seller told me that the HP were for a long time in the box. They are wery dirty - from box's black foam I think. I cannot see any hair on the driver.
What was suprise for me that after a while - I think after 2 hours or so - it was much better but still some rattle on some bass frequencies...