BTW, as we are on a stax-nakamichi page, I think I can say what I lately discovered : I tried to turn a stax sr-3 to pros ( 5 pins instead of 6 and pro votage. For a few minutes, the soudn was astounding and surpassing the srx III pro.. and then It turned bad and ill balanced. As I had three diifferent sr3, I dismenteled two of them, ( I will sell the last shortly on head fi with a good deal of other ones, coming from my collection). and I understood that for this one, the highr voltgae could not work, and destroyed the membranes. which never occured with the srx norm bias.
Also, I could notice that there were a least two types of crivers for the sr-3 ( not talking about the sr-3 new, that i don't own). the first type, that is probbaly the oldest, has an aluminium membrane for the sound. and the newer one has a mylar membrane. just like in the srx. the aluminium membrane is sounding a bit poorer than the mylar. I made differents tests, hanged the destroyed membrane, and finally made the sr3 work on the normal bias of my amp. the sound is very nice, but not as clear in the highs as the srx, and it is bassier than the srx. I don't know if anyone had tried this before on the sr3, to use it on pro bias, but it is not to be done.
with the aluminium membrane, it didin't kill them nor damage them in any way, but I had a very strong electronic and continuous noise if plugging it in the pro bias.