WOW--that link is a GOLD MINE of information on tubes! Check this out:
**** THE NEVER ENDING KT88 RE-BRANDING LIST ****
(THIS IS WHAT YOU CAN GET, BUT MAY NOT NEED IT)
Don't let anyone mislead you. If there is one tube that a whole crowd of fakers have jumped on, a long time ago, it is the KT88. Every self-respecting faker has "finest" KT88 for sale, and his own brand. Of course, some respectable companies also make finest KT88, but how to keep the those apart? Apart from the Tesla re-brands and re-makes, these are probably all China tubes and.... ALL come from the same factory in China.
When I first ordered tubes from CEIEC China in 1997, there was the sales engineer, who some of you perhaps still remember, his name was Mr. Li. He told me: Sir, what brand do you want on them?... I said: Well, your factory brand of course! They said: yes sir, we have that too. I was so shocked by this. This shows how easy it is to get "your own" great brand of Chinese tubes. However when you know the Chinese better you will learn that the way to get quality from them is hard, very very hard, and impossible for most. For them, something that "works" good is a fine product. They sure can make quality but they prefer to sense very delicately what your minimum acceptance level is, and simply send you that. So you won't complain, and they can send you the lower quality, that they know some other company will reject. (or has rejected, and send back). A lot depends on how having a long history with your purchasing channel, and how they have learned about you, and what you find out and not find out.This problem comes from one particular and actually quite normal Chinese trade method. That is, you are supposed to pay the price they ask, when it is a reasonable price for you personally, like they know it, and like you know it. If you THEN bargain on the price, they regard you no future business partner any more. You lost your face. Speak in our words, they regards you dishonest. Next thing is, they send you lower quality, that they feel better suits your dishonest price. This they do with an oriental smile on their face, and you get screwed of course. For them this is not screwing, it is giving you what you deserve. The other way around doesn't work, like giving them a real good price and expect real good stuff. They think you must be pretty stupid. So you see, how hard this is, and why so many bad Chinese tube stuff is around. There just is no good way to talk straight with them.