274b's instead of 5u4's

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Berndt

274b's instead of 5u4's
« on: 28 Jun 2009, 01:35 am »
both my pre and phono stage utilize 5u4 rectifiers and have recently gotten a hold of some shugang(sp?) 274b's for 30$ ea that take me another step in the 3d imaging direction.
The 274's have a smooth and extended topend that the 5u4's didn't have.
Not comparing to the eml 5u4, just nos sylvanias.
I like running new tubes that are cheap, these are tough to beat for the $$$.

Regards, Bill

Scott F.

Re: 274b's instead of 5u4's
« Reply #1 on: 28 Jun 2009, 01:57 pm »
Be careful using the 274A as a direct, drop in substitute for a 5U4G. It will work just fine IF the design of your power supply will support it. Assuming you have a standard CLC filtered power supply circuit, the first cap after the 274 can be no larger than 4uF according to the published data by Western Electric.

If you install it with a first filter cap larger than the 4uF, it will work.....for a while, then it will self destruct likely taking out the power supply transformer and at minimum the first filter cap and likely the choke follower when (not if) it shorts out.

That said, I have no idea how the Shuguang specs read. They may have deviated from the WE design...which wouldn't surprise me.

The 274A in a proper circuit can sound wonderful. Cleaner, more open, blacker background, it is a great rectifier tube. You just need to be cognizant of the design of your power supply.

For those curious, you can download the spec sheet on the WE 274A form this site.....

http://www.mif.pg.gda.pl/homepages/frank/sheets/136/2/274A.pdf

Niteshade

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Re: 274b's instead of 5u4's
« Reply #2 on: 28 Jun 2009, 03:16 pm »
Are you sure you want to use 274B's? If you have some on hand, that's OK but I would not actively seek them to use because they cost too much. I just saw one on Ebay going for over $1,000!

The 5U4 & 5AR4 series rectifiers are excellent and inexpensive.

Collector prices and actual value are often light years apart.

dangerbird

Re: 274b's instead of 5u4's
« Reply #3 on: 1 Jul 2009, 10:50 pm »
Are you sure you want to use 274B's? If you have some on hand, that's OK but I would not actively seek them to use because they cost too much. I just saw one on Ebay going for over $1,000!

The 5U4 & 5AR4 series rectifiers are excellent and inexpensive.

Collector prices and actual value are often light years apart.
Very well said sir. :thumb:

Berndt

Re: 274b's instead of 5u4's
« Reply #4 on: 1 Jul 2009, 11:56 pm »
I started with 5ar4's, switched to 5u4's and added the stand by delay switch.
The 5u4's Ive been using are the sylvanias that have a very nice bass drive in my rig.
Along comes the 30$ 274b which is about the same price as the nos 5u4.
I showed the specifics of the tube to my buddy who came up with both the pre circuit and the phono stage circuit and he says don't worry, run it.
For a 30$ rectifier this is a larger improvement in my system to my ears than any other rectifier change has made.
I am not interested in running some weirdo uber expensive nos tube, even if it is not weird, just expensive...
The shugang 274b has about 15 hours on it and I ordered a second one for my linestage.
After everything that has been said about the EML 5u4 I thought the shugang deserved a shout out as well.
regards, Bill

Niteshade

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Re: 274b's instead of 5u4's
« Reply #5 on: 2 Jul 2009, 10:56 am »
I was thinking of the 274B purely from a vintage standpoint and never considered an Asian remake. One of the best 6SN7's made is by Sino, so it doesn't surprise me if another good one shows up.

ohenry

Re: 274b's instead of 5u4's
« Reply #6 on: 27 Feb 2010, 01:21 am »
Another glowing (yuk, yuk) account of how good the Shuguang 274B rectifier is in my 45 pp amp.  It does wonders for imaging and it has a seductive silky character without losing detail.  It has a similar character to the expensive Sophia 274b in my application and it's only $21.95 tubeman.com:
http://tubeman.com/item524.htm

I have rolled quite a few NOS rectifiers in this amp (5U4g, 5U4gb, GZ32) of different manufacture and this one works for me.  :wink:

I want to include that tubeman was super quick and called me immediately when there was an address question.  Nice guy and great tube.   :thumb: