The second replacement pair I received #93 has been going strong for two weeks now while the first two exhibited troubles within a couple of days of use. I did get the sense from the clerk, who indicated that he had called Stax, that there had been some sort of delay in production between the time of the first shipment (with the first two I had 62 & 14) and a second shipment with my current pair. There definitely was a bit of a language barrier so I would not swear to the complete accuracy of that last bit of information though. I do know for sure that there was a waiting period that had to do with getting another pair from the manufacturer and not from waiting for additional stock to be sent from the store's headquarters.
Just to add another clue for the investigators on the Case of the Imbalanced Stax 009 Drivers:
The second pair (#14) worked fine for a few days and then started to go in an out of balance with the right driver losing volume. However, while I was waiting for the replacement pair, it actually stabilized and went for a week with no issues. Whereas I could previously affect the issue by pressing the cups down uniformly or alternating pushing side to side, during the stable period, that kind of manipulation had no effect. This actually caused me troubles when I went in to exchange them because they worked fine for the clerk when he tested them in the store and I had to argue my case that they had in fact malfunctioned when I first got them.
No doubt dealing with this has been a hassle and consumed a fair amount of time and energy, but the whole time that all has been secondary to the fact that these phones are a significant step up above any pair of headphones that I have owned or heard. It was always in my mind that it was just a matter of when the problem would be resolved, not 'if'. For a lesser pair of phones, I would have given up, but for these, it has been completely worth it.
I am really looking forward to other members getting their pairs. Stock does seem a bit more plentiful in Japan and with a few more new owners from Europe chiming in, hopefully it will not be much longer.