Reviewed by Tone Audio (Issue 2)

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Pricing:
Option 1: $210 per Princess 274B or 274A mesh plate tube with one year warranty.
Option 2: $160 per Princess 274B or 274A mesh plate tube with 30 days warranty.
Option 3: $175 per Princess 274B or 274A rigid plate tube with one year warranty.
Option 4: $130 per Princess 274B or 274A rigid plate tube with 30 days warranty.

Shipping:
For U.S. domestic shipment, we use USPS priority mail with insurance -- $10 for the first unit, $3 for each additional tube. Express shipping is also available at higher shipping cost.
For international shipment, we either use DHL or USPS express. Please email us your country and city, so we can find out the shipping cost for you.

Feedback by Mr. Fred Volz, Emotive Audio

Your Sophia Electric™ mesh plate 274B is the best rectifier tube I have ever heard including the actual Western Electric 274B. This is quite an accomplishment and you should feel very good about this. I let my Canadian distributor hear it in his Sira and he refused to let me have it back. So, now I have only the one left and it must go to a customer soon. So, I will be ordering more. I will also recommend them to anyone who buys one of our preamps.

Fred Volz

Emotive Audio

Sophia Electric™ 274B tube is a premium rectifier tube for a 5U4/5R4/5AR4* direct replacement with 3X longer plate structure, thus it has a deeper, wider sound stage and even smoothier sound than Mullard 5AR4.

Historically, WE 274B was designed for the WE300B amp, the current NOS WE 274B is $1000 each unit(see Vacuum Tube Valley magazine), the used one can be as high as $500 on Ebay. According to a recent test, this Sophia Electric™ 274B tube outperform the NOS WE 274B by higher current capability, which translate into better bass, dynamics, and deeper sound stage.

The sonic difference comparing to conventional 5U4, 5AR4*, 5R4 is far bigger than any cable upgrades combined in a high end system.

Sophia Electric™ 274B is 8-pin octal-based tube and Sophia Electric™ 274A is 4-pin based tube. Our friend Art Audio is using Sophia Electric™ 274B in the Art Audio PX-25 amplifier.

Note(*): 274B is direct heating tube. The indirect heating 5AR4 may turn on slower, however, people who buy 274B is for its superior sonic performance. To fully utilize its benefits, it may require first stage capacitor (capacitor input) to be less than 10MFD, or 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 to your amplifier maker or refer to a tube manual. This 274B is an update of the NOS WE 274B, so both share with same characters. In 1930s, WE 274B was the rectifier choice for 300B single ended theater amplifier in the US.

The maximum current capability for Sophia Electric 274B mesh plate tube is 90ma, suitable for tube pre-amp and mono-block 45 single ended and 2A3 mono-block single ended.

We would recommend Sophia Electric 274B rigid plate tube for 300B amplifiers. The maximum current capability for this 274B rigid plate tube is 160ma.