For sale is my Stax sr-507. I've had them for about 6 months and have babied them the whole time. When not is use they were kept in a dehumidifier cabinet, keeping them safe from dust, kids, and humidity (duh). They are in excellent condition and have absolutely no channel imbalance. They also come in the original packaging.
I like these headphones quite a bit, and am only selling them because I need to payoff my TH900. If I didn't have to do that, I undoubtedly keep them, even though I have a 007.
If you're not familiar with the 507, I encourage you to read the 507 appreciation thread. You'll see that many consider them on par with the HD800, and to have a sound signature similar to the 009. I wouldn't know because I've never heard either, but I can say that they are excellent.
I'm selling these for $X Buyer pays shipping, but I'll cover the PayPal fees.
If you have any questions, please do not hesitate to ask