I've had issues with my Aqua II rectifiers, but not that one. If it is indeed a normal thing. . . that shouldn't last long. But as I have had several and have not had that issue. . . it makes me think that it is not a normal thing if it persists. I'd ask Sue if she would allow you to return it for assessment and replacement.

The issues I had were of my own making I believe. I've come to realize that they may not be an ideal tube for the SEWE300B, though they work great in the CSP3 and the Zen-clone amp I have. I blew one of them by turning my amp on and off too often when testing fuses and the direction of the fuses. And then I blew a second when I was installing a Swiss Digital Fuse Box. . . I am not sure exactly why that happened, whether the initial turn on of the Fuse Box caused it to blow, or if it was a defective one (only had it going a few hours at that time). I got a third and it seemed to work okay with the SEWE300B but I just was anxious and untrusting and put it into the CSP3 and then the Zen-clone amp. It was hard to find a rectifier to replace it with. I have three of the original Aquas which are great tubes but not quite like the II. And then I had a hunch that a Psvane Treasure 274B-Z might be a good one, as it resembles so much the Shuguang Black Treasure 300B-Z tubes I adore in the SEWE300B and it has proven to be a fantastic rectifier for that amp. And I bought another that is fantastic in the CSP3 and I put the Aqua II in the Zen Clone amp (the CSP3 and the Zen-clone amp are the heartbeat of my living-room audio/visual system).

So. . . that's my history. I don't think the failures were the Aqua II's fault though I do think the demand that the SEWE300B seems to put on it may mean it's best for me not to use it there.

The original Aqua amazed me at first listening and I used them for years. . . . The II is an improvement, a bit better bass, a bit sweeter treble, a bit blacker background--they are both excellent rectifiers.

I had a Sophia Aqua II Rectifier that was dead on arrival.  No sound at all.  Seems failures are the risk you take buying these rectifiers.  Not for me. Lon recommended the Psvane 274B-Z Treasure series and they are a really nice sounding tube.  Checks all the boxes and can be bought for $60 on Aliexpress.  2 weeks delivery.  I am shocked how good they sound on my set up after 100 hrs.

Thanks Lon, Tony, and Hearafter. I appreciate your input. I'm keeping my fingers crossed that the new Aqua II heading my way isn't another dud.

Those of you who've heard both the Aqua II and the Psvane 274B-Z, how would you compare them? I am considering picking up a Psvane 274B-Z because the price is right, and I might as well have a safety net to keep rocking should the new tube fail too.