Preferred Series 274B / 5U4G
This tube is produced for us in China by the Shuguang factory. A new evacuator is utilized for a much longer time period increasing vacuum over 100 times more than their current 5U4G tube. A new cathode coating process provides a much smoother finish improving electron flow and they are burned in at high voltages for a much longer time for improved stability. The end result of utilizing these new production materials, techniques, and equipment is a premium rectifier tube at a much lower cost than the NOS Western Electric 274B.
As a Preferred Series tube these are further tested on our digital high voltage equipment to make sure the tubes selected for you will provide outstanding tone and performance.
Warranty: The Preferred Series 274B tubes carry a 6 month extended warranty.
Other Preferred Series tubes 
5U4 TypesWarranty Information and Return Policy
Warranty Period: 6 monthsPreferred Series tubes have a 6 month warranty from date of purchase. (Any exceptions will be noted on that tube's Warranty tab)
If you receive a tube that does not perform to the manufacturer's specifications, please do the following:
- contact us to get a return authorization
- return it via regular mail within 180 days from when we shipped it, and we will provide an exchange or refund of the full purchase price of the tube.
Returns not related to warranty or defect will be considered at our discretion, and are subject to a 15% restocking fee.
We can not accept returns that don't have an authorization, are past 6 months, or are returned improperly.
These guidelines may be updated without notice.
Ratings & Reviews
7 reviews
Sounds great but keep an eye on them during start up for at least a few weeks.
by Robert
Got my first two in a couple of weeks ago. They still sound great, but one started to do things I've never seen a tube do. As though surge goes up and a small piece of burning filament falls back down. I have tried it on both my mono blocks and on my 2a3, does it on all 3 amps. The other 5u4 is working just fine. So happy to see such a great warranty so will be replacing and buying two extra.
Reliable and good looking
by Breanna
What can you say about a full wave vacuum tube rectifier? It's monstrously inefficient, oversized, and gets painfully hot during normal use. In other words it's exactly as it should be. The ST style looks excellent and the tube has been entirely reliable for a year so far.
Mine had a tiny piece of glass that rattles around inside. Amusing but harmless. Wholeheartedly recommended.
No, it doesn't affect the sound. It's a rectifier. Jeeze. Audiofools will believe anything.
Great rectifier tube for pre-amp, and at a reasonable price.
by Mark Ainsworth -
I replaced the stock tube in my Aric Audio Transcend pre-amplifier with this one. While the preamp was wholly satisfactory with the stock rectifier, this tube seemed to give me a little more space and extend the bass a bit. Note: I was unable to do side by side comparison, since the original tube had burned out.
My go-to tube rectifier
by Phil Ressler
In hifi use, this rectifier has NOS Mullard GZ34/5ar4 in all of my gear that is tube rectified. It neatly splits the difference between the euphonically forgiving-but-undisciplined sag of a 5u4, and the sometimes-too-tight-sphincter of a vintage 5ar4. In Melody Pure Black 101 and P7688 preamps, and in Quad II Jubilee power amps, I get burstier dynamics, deep bass finesse without bloat, best soundstaging and fluid musicality that exceeds any other rectifier I've used in the last 40 years. Also has proven durable. I also use it for tone and dynamic improvements in guitar amps where it fits.
274b Rectifier tube
by Paul L
I recently had a DHT preamplifier built and choice of 5U4G or 274B. This 274B rectifier tube is a great tube for the money it has a nice smooth balance.
Adds nice depth and very stable expanded soundstage. Very close to the Sophia in quality for far less money. To get noticeably better you would have to buy the Emission Labs 274, but is expensive.