Mathew,
I bought a Cayin TA-30 from "that guy on AudiogoN". That guy is Paul Grzybek and he owns a retail Audio store, in the Chicago area, called Bizzy Bee Audio. He specializes in rebuilding vintage tube receivers and he is probably the biggest seller of Cayin TA-30s in the US. Because he is a guru on tube amps, he has also developed some exclusive Mods for the Cayin TA-30.
The $499 version is stock from China and does not include any mods. If you want to perform bias adjustments or use the amp in SE mode (as described on Paul's web page), you will have to turn this version over, remove the bottom cover and expose yourself to 450v in order to perform the bias adjst. This is OK for me since I have experience with this sort of thing, but if you don't know what you are doing or don't want the hassle, I would suggest at least getting the external bias adjst mod.
I bought the $499 (slightly damaged box) version and quite frankly, the external box (it is beautifully packaged in double box with molded foam insert) was no worse than ANY box I've ever seen shipping via UPS or FedEx.
Now, about the sound: IT IS INCREDIBLE for this price range. I've owned at least 10 amps in the last 2 years, including some that cost over $2000 new and I can tell you, the Cayin is VERY GOOD. Because it is an integrated amp and can be used in P-P or SE mode, it is very versatile and that also adds to the value. Build quality is ABSOLUTELY first rate too. It looks spectacular in person (with the tube cover removed, of course!).
I could not recommend the Cayin TA-30 more highly. I love mine and I'll ultimately send it to Paul for his inexpensive mods (external bias adjst, focus mod).
It is really a cool piece and a great value......
http://www.2baudio.comBTW, I have no personal or professional connection with Paul G. or Bizzy Bee. I'm just a happy customer.
Enjoy,
TIC