Has anyone bought the Psvane Acme 300B Vacuum Tube?

Please correct me if I have misunderstood what is being communicated in some of the above posts regarding 'resolution?'

In particular, I do not get how a specific tube can be "more resolving" (in the midrange... I presume) yet be simultaneously rolled off above and below (in the frequency range); in other words less resolved above and below.

I would agree with your assessment and understand what you mean by the Taks being more resolving. Sometimes there is just more there in the midrange, even if it means being more relaxed at the frequency extremes!

Don't buy EML tubes. Their 5 years warranty is crap.

I bought a pair, one failed only with 10 hs or so of use and they blame my amp as they said it had lower heater voltage than "recommended" by them. 

Well, my amp had about 7% lower than the 5v ideal heater voltage and they cover up to 5% of difference. 

I consulted other experts on the field and no tube can be broken by low heater voltage. I have Shuguangs and Golden Lion 300B working fine for years that back up these experts opinion.

Summarizing, don't buy EML and if you are an EML fan, I can sell you a brand new EML XLS 300B single tube, I cannot use alone, with a good discount.

I have had the opposite experience to you. I've owned a pair of EML 300 XLS for almost 6 yrs, and they are still going strong with no issues whatsoever. I've had terrible experiences with Sophia Electric Princess 300bs, where I had two different pairs fail. They tried to blame the failures on my amp, which of course isn't true, because they were the only brand that ever failed on my amp. I have nothing but high praise for the EML tubes, they sound amazing and are beyond reliable in my opinion. 

@spratan I have nothing but high praise for the EML tubes, they sound amazing and are beyond reliable in my opinion. 

100% agreed. I just replaced a pair of the EML XLS 300b after 12 years of very frequent usage in my 300b SET mono blocks. They provided superb sound quality and not a single reliability issue. I fully expect the same from my new replacement pair.

Charles

Correction I’ve had the EML XLS tubes over 10 years (purchased in 2012).

Charles