"One thing I am certain of, Chinese tubes are getting better, and they will be up there with the good tube makers, and perhaps wind up being the best of all!"
I couldn't disagree more, Chinese tubes suck!
I have two Chinese amps.The Bada DC-222 integrated amp that came with stock 12AU7 Chinese tubes and a Shengya A10CS Hybrid Integrated Amplifier that also came with stock 12AX7 Chinese tubes
Both amps didn't sound good at all at first, then I replaced the tubes with some cheaper NOS ones and now the amps sound great!!
The Chinese are starting to make some really good sounding gear but they have a very long way to go in regards to tubes! I personally haven't heard any good Chinese made tubes as of yet, in fact I throw them away.
You don't have to spend a fortune to get some really good sounding tube replacements. You can buy some nice NOS 12AU7 GE's,RCA's, J&J's among others at very decent prices and as far as the 12AX7 tubes there are current production tubes that are really good like the re issued Tung Sols and Mullard's.
This came from the Pacific Value site that sells your amp.
We recommend that you leave the JJ blue tubes in there as these should
be the last to go.
Get rid of the stock 12AX7 / 12AU7.
Try the Mullard 12AX7s - these worked the best. For 12AU7s - try the GE 5963s or the Sylavania 6189s both of these tubes worked well.
Need more bass? Try the EH 6CA7s - very good tube for the money.