NOS Sophia Electric Princess 274B Rigid Plate Rectifier Tubes
We found a few units from our warehouse. The price is for one unit with 30 days warranty.
Sophia Electric 274B tube is a premium rectifier tube for 5U4/5R4/5AR4* direct replacement with 3X longer plate structure, thus it has a deeper, wider sound stage and even smoother sound than Mullard 5AR4.
Historically, WE 274B was designed for the WE 300B amp. The price for a used WE 274B is in the range of $2,000 - $4,000 a piece with no warranty. Based on end-users reports, Sophia Electric 274B tube outperforms the NOS WE 274B by higher current capability, which translates into better bass, dynamics, and deeper sound stage.
The sonic difference compared to conventional 5U4, 5AR4*, 5R4 is far bigger than any cable upgrades combined in a high-end system.
Note(*): 274B is a direct heating tube. The indirect heating 5AR4 may turn on slower; however, people who buy 274B are for its superior sonic performance. To fully utilize its benefits, it may require the first stage capacitor (capacitor input) to be less than 10MFD; otherwise, it would shorten the 274B life span (very much like smoking is bad for your health). It would not be a problem with common choke input. Please consult your amplifier maker or refer to a tube manual. This 274B is an update of the NOS WE 274B, so both share the same characteristics.
The maximum current capability for this Sophia Electric 274B rigid plate tube is 150 ma, suitable for tube pre-amp and mono-block 45 single ended and 2A3 mono-block single ended.
We would recommend Sophia Electric Aqua 274B rigid plate tube for 300B amplifiers. The maximum current capability for the orginal Aqua 274B tube is 160ma and 220 ma for the Aqua II 274B.