Hello, all. I'm a relative newcomer to tubes, but I have a Modwright KWH 225i hybrid integrated amp that came with a pair of JJ E88CC triodes in the preamp section (upgraded to 1960s-era Holland Amperex) and a Modwright PH 9.0XT phono stage that employs a Russian 5AR4 rectifier in its separate power supply and a pair of 6C45s and a couple of E88CCs in the phono stage itself.
After the 5AR4 died I replaced it with an identical new Russian tube. As I've spent more time listening, however, I kept feeling that the tube might be holding the sound back a bit. Notably, there was a bit of upper midrange mud that I didn't hear when listening to my digital side, along with some soundstage constriction.
A week ago I decided to take a chance and replace the phono stage rectifier with a Sophia Electric Aqua II 274B. What a difference!
As a brand new tube, I expected the Aqua II to take some time to get comfortable. Right out of the box, however, the upper midrange was significantly cleaner. It wasn't that the overall sound had become leaner; rather, it had eliminated the slightly muffled thickness that was there before while leaving the overall weight and timbre intact.
I've continued to enjoy the Aqua II's performance, noting a wider and deeper soundstage as time goes on. I'm quite sure that the success of any tube is system-dependent, but I encourage you to not shy away from trying out the Sophia Electric Aqua II 274B Rectifier if you have the opportunity.