Western Electric 300B problem

Some tubes fail early. Not often, but they are not like iPhones and computers. It happens occasional... especially after shipping. There is a whole bunch of suspended stuff, in a vacuum, with a lot of heat. So, I would not condemn the brand. Just get a replacement. And, with tube equipment you should always have a spare tube set. Just in case something comes up, you can swap out your tube set and evaluate the problem.

I run over fifty tubes(on a daily basis) and have only gotten a whistle in a tube getting close to the end of its life three years ago and one dead on arrival five years ago.

I had a heater die (go open) lately on an 80 year old tube.

Thing is I  heard WE had recently improved evacuation equipment, this failure betrays that. This also not the first I've heard about gassy WE300B's, red plating has also been an issue with higher plate voltages of some amps. Max rating on Acme 480V, WE450V.

Never had an issue with 300B tubes prior to this in either my 300B monoblocks or as drivers in my 845 SET amp. Shuguang and Acme's. I've had some failures with 101D tubes in my pre, both Linlai and Psvane.

I'll just go back with Acme's in amp, have absolutely no issues of any kind, sound quality fantastic, just wanted to hear what WE brought to the table. What I heard in first five hours was very nice, just a bit rolled off on top, darkish tonality, resolution/transparency very nice, right up there with Acme.

Have you compared EMLs?  I use those in my dac.  where do you buy your ACMEs?

A brand new tube is mostly to fail during the first 10 hours of use. 

Warning, if you are going to buy expensive new production tubes for investment or future use, burn them in during the warranty period before you put them away.