As Gopher knows, I have been running the Psvane 845's in my Mastersound amp; the amp came with some 'generic' labeled 845s (I imagine they are the stock Shuguang's, but certainly don't look like the 845B's, so I think they are just the "845's"---I received the Psvane's shortly thereafter and they were a nice improvement over the stock 845's that came in my amp. I've done lots of reading about 845's since then, and the descriptions of the 845B's interest me enough that I may spring for a pair to try--I just want to be sure that the 'generic' 845's that I already have aren't 845B's. Do all the 845B's have the 'copper' colored base?
Also, I used Psvane 12AX7's in my previous amp and was really impressed; my Mastersound 845 uses a pair of 12AU7's--I haven't found the Psvane 12AU7's to do too much for me in this amp, the sound is kind of boring. I'm much preferring other options, like CBS 5814's, Amperex 7316's and Mullard long plate 12AU7's in this amp.