So my beloved Aqua II arc’d a couple of days ago. I went on to the Sophia website to check availability and saw this message on the Aqua II webpage:

Attention Decware SE84UFO owners: The Sophia Electric Aqua II 274B rectifier may not be compatible with your equipment. We recommend using the Blue Glass 5U4G instead.

This is a bit unsettling considering the Aqua II was assured to work with Sarah over the original Aqua, back in 2023.  I figured I’d let other members know considering it’s a popular tube in these circles.

I reached out to Sue and she informed that due to the high rate of failures, they put this cautionary language up last month.  I’m not interested in tempting fate and moving away from this tube.  Currently back to enjoying the Cryotone 5U4G  (my second fav) and considering alternatives.

Gosh Kam, sorry to hear that and read the info Sophia Electric posted. I had one fail on me when I introduced the SDFB to the amplifier, I was blaming the SDFB at first, not sure why that happened actually. I replaced it with an Amperex 5R4WGB that I have on hand, a great rectifier and then with the Psvane 274B-Z mentioned by Hereafter--a great rectifier. I'm also using a Linlai 274B-D Dream rectifier, which is closer in sound perthaps to the Aqua II--bigger image, bolder sound. Very nice! No arcing on these.

I actually have about two dozen NOS rectifiers and each sounds a bit different in the amplifier--there are many possible sound configurations with some exploration. I'll be putting some up for sale soon. I have narrowed down the "field" of tubes that I love in the amp.

I remember having had similar reservations about the specs or lack there off from their homepage and having written to them with questions in regards to the Aqua´s tolerances of first capacity size when used in a CLCL filter (my Zens are modified with chokes) and getting a rather clueless (first filter 47uF ) reply. I was running 32 UF as the first filter and noticed flashing on one of the Aquas at start up (never a good sign) so have them sitting in their boxes for now as not had the inclination to dig into the power-supply filter just now to lower the first cap again but plan to install 16uF´s in the first cap position and might test them again.
Main problem I see with Sophia is their lack of documentation or measurements with their products they say nothing about why they dont recommend Aqua II´s in the UFO´s which by the look of it is very similar to the modified Zens I´m using, where are the Data sheets ? Does not inspire confidence as they could have told them selves the UFO´s would have a problem as I sent them basically the same power supply diagram as a question last year as there is no diagrams or dissipation curves posted anywhere about these tubes and seems like they didn´t take into account that it´s not just the first cap value in a filter stage that matters but also what sort of filtering stage it is.