Thank you for advice Tigz. Occasionally I feel back pain, but never had problems with neck. I hope stretching will help, because at the moment I don't know where to go (T1, HD800, etc.) if I wasn't able to listen to LCD2
As I recall from krmathis post (can't find it at the moment) this is because of machinery, which had made drivers for K1000. Over the time it wear out, and thus there are two versions of K1K. Sorry If I have missed some details regarding this matter.