Hello Western Electric 300b!
Since my Psvane Acme 300b tubes flashed white and sent my Cayin Ha-300 amp to repair (replaced a wire-wound resistor) last month, I thought might as well upgrade my tubes, and the Western Electric 300b was the obvious choice.
Took almost 3 weeks to have one allocated and shipped straight from the factory, but it's worth having.
Compared to the stock TJ Full music, this is already a much more dynamic, musical tubes. Better mids, open treble, tight bass, wider Soundstage, and much better image separation are what I noticed right out of the box.
This is also a better tube than the Psvane Acme 300b tubes, at least out of the box, but not by a substantial amount. I'd be willing to bet the sound will continue to get better after a few hundred hours, though.
What I also noticed at first power on, though is a lot of clicks, pops, and pings, which freaked me out, but they disappeared after a few minutes. I did read this is common with these new tubes, so crossing fingers.