Stts, believe it or not, ebay. Several years ago, I found a guy selling them who lived about 20 minutes from me, and I may have bought 20 for something like $75. There's a whole raft of them on ebay right now, often called 12AX7B or Silver Dragon, at very low prices. Again, I'm quite curious about the Pavane/Psvane myself, but thus far have been very happy with the ones under discussion.
A friend of mine turned me on to them in his Quicksilver amps, which came with them. He had every intention of upgrading them, as I believe he had a big stash of Telefunkens, and Mike Sanders told him something to the effect of, "You can try, but you'll probably put these back in."
Well, I was skeptical to say the least. So, I tried them, and lo and behold they beat my Mullard Blackburns, though I still could not believe it. I had a tube collector friend with very discerning ears try them in his system, and he agreed. Then, to get some real consensus, we had a blind tube shootout over my house with them as the driver in my Jadis DA60 with a bunch of folks in our audio group. It placed in the top three, along with the Telefunken ribbed plate and my personal favorite Sylvania Triple Mica Black Plate 5751. Those three beat out the Telefunken Smooth Plate, Mullard Blackburn, GE 5 Star 5751, EH, Ei, JJ and Sovtek. For the record, in my application, I still prefer (and, it's not as that close) the Sylvanias.
One note, make sure these Shuguangs have the triple mica.
