I have a Stax O2 mk1 in nice condition that I'd be willing to sell. I am only selling it because I came across a mint condition set. I've had this headphone for about a year and it could very well be the best headphone ever. Note that this is the mk1 and not the mk2. I have many of the high end headphones and consider this the overall most accurate headphone. Impressions can be found all over the high end forum and more recently in the Bay Area Meet thread to give you an idea of how well this headphone can scale with something like the Blue Hawaii. There is only one minor cosmetic issue: on the grill of one of the cups there is a small black spot. This is very minor and I don't think most would notice it, but it's in one of the photos.
I will only accept check, money order, or any online service other than paypal as I no longer use paypal. If you find another online service that you'd like to use I'm all for it. I have perfect feedback here, on audiogon, and on ebay and go to many meets so I'm not disappearing on you anytime soon. Feel free to send offers. Given that this headphone is in very high demand, I will ignore all low ballers and will pick whomever I want to sell it to. I will try to answer any questions you might have in PM in a timely manner.
