What is the best 5U4G ?

sujay

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May 5, 2012
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#21
The RK 5u4g is excellent indeed. Way quieter than the limited KR lampi 5u4g I had previously. I hear more detail, the soundstage is wider and more layered. I haven’t tried any other 5u4g but I should get my Acme 274b soon.....will be interesting to compare
 
May 30, 2010
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#22
Tube rectifiers can be very critical depending on the circuit. As usually these circuits do not have a stabilizer after the rectification section, different types of tubes will result in significant changes in power supply voltage and sound characteristics.

Tube rectifiers need burn-in time - noise usually reduces after 50 - 100 hours, as the noise emitting cathode micro-whiskers smooth.
 

Joao@altheamusica

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Sep 20, 2010
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#24
The RK 5u4g is excellent indeed. Way quieter than the limited KR lampi 5u4g I had previously. I hear more detail, the soundstage is wider and more layered. I haven’t tried any other 5u4g but I should get my Acme 274b soon.....will be interesting to compare
You should take care of the limiting value of the firts capacitor after the rectifier... a 274b is very critical here! Amother "sound factor" is how much voltage drop does the rectifier have. So a professional statement / compare can only be done by observing and adjusting the operating voltage (B+) of the amplifier (and of course the other operating points of the tubes). Happy tube rolling...
 
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bonzo75

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Feb 26, 2014
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#25
All of these new tubes these days stink. I will always go NOS with any and all tubes I need.

A few years back, I had an old converted and heavily modified Baldwin organ amplifier that required TWO 5U4G's. After rolling in a few new and old tubes, the absolute best ones were a matched pair of NOS Westinghouse 5U4G's with a quad set coin-base Russian 6N3C-E (6L6GC equivalent) output tubes.

Those particular 5U4G's added weight, grip as well as added space and air to the overall sound. It made that amp sound a lot more powerful than it's 23-28 watt output. At the time, I was powering a pair of NHT 2.9's with it and that amp had zero problems getting them to pretty loud levels... Cleanly.

All of the other 5U4G's that I tried just sucked the power and life out of that amp. It was weak, anemic, had background noise and just blah sounding. Those newer tubes included EH, Mesa, Psvane, Shuguang, and some JJ's. Oh, and some Golden Dragon's that didn't even fit because the envelope was too large.

I really miss that amp and wish I still had it, but it was my oldest brother's amp and I just had it a few months to make the repairs/mods/upgrades to it and run it through its paces before giving it back to him.


The Westinghouse was very good in Al's system, better than Tak, more linear, and in some ways better than the older KR. JJ, Psvane, shuguang are not in this league. I would like to listen to the Westinghouse more and the WE 274b
 
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May 3, 2017
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#26
For the Allnic H3000, how do you think the 1940s RCA Double D-getter would compare to the new KR RK 5U4G?
 

Uk Paul

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Sep 27, 2012
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#27
For the Allnic H3000, how do you think the 1940s RCA Double D-getter would compare to the new KR RK 5U4G?
Hard to say without direct comparison; the RKKR is my preference over KR lampi Anni, Ayon mesh, Philips 5R4GYS, Mullard GZ34, plus a box full of others, all in H3000.
 
Likes: bonzo75
May 3, 2017
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#28
Thanks!
 
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#29
What do you like about it in the H3000?
 

Joao@altheamusica

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Sep 20, 2010
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#30
Hard to say without direct comparison; the RKKR is my preference over KR lampi Anni, Ayon mesh, Philips 5R4GYS, Mullard GZ34, plus a box full of others, all in H3000.
The GZ34 is a total other kind of rectifier tube like the 5U4G... have a look at the data sheet! It owns a voltage loss compared to the 5U4G discussed here. See my posting #24 above for further details, so it's not a fair comparison you made
 

Uk Paul

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Sep 27, 2012
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#31
RKKR has good drive in H3000, and fine detail, indicating spacial cues very naturally, which Lampi Anniversary does well too, but RK Ltd has quite a punchy sound which I need with my Logans, it's all system dependent though..
(FYI- On H3000, changing input impedance resistors to Vishay Z-Foils shows bigger differential between rectifier tubes).

Rgds,
Paul
 
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Uk Paul

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Sep 27, 2012
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#32
The GZ34 is a total other kind of rectifier tube like the 5U4G... have a look at the data sheet! It owns a voltage loss compared to the 5U4G discussed here. See my posting #24 above for further details, so it's not a fair comparison you made
I know, but i was stating experience with rectifiers used in H3000 specifically, which GZ34 works fine.
 
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Joao@altheamusica

Well-Known Member
Sep 20, 2010
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#33
I know, but i was stating experience with rectifiers used in H3000 specifically, which GZ34 works fine.
Yes but with more plate voltage you are changing the operating points of the stages... that's the truth! Do you have a schematic of the H3000 that you can observe if the rectifier you are changing can is suited for using it in this design?

Musical regards
 
May 30, 2010
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#34
Yes but with more plate voltage you are changing the operating points of the stages... that's the truth! Do you have a schematic of the H3000 that you can observe if the rectifier you are changing can is suited for using it in this design?

Musical regards
Yes, but IMHO it is what most tube rollers really want - change the sound characteristics of equipment to tune it to their preference! Changing the operation points is just an way of doing it. There is no fair play in this game, smoke is the limit! :)
 

bonzo75

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Feb 26, 2014
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#35
For the Allnic H3000, how do you think the 1940s RCA Double D-getter would compare to the new KR RK 5U4G?
I have compared to RCA don't know if it was double getter, the KR was much superior, and the RK is better than the KR
 
May 3, 2017
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#36
I have compared to RCA don't know if it was double getter, the KR was much superior, and the RK is better than the KR
Interesting. I was hoping you would reply as I figured you have compared them.
 

bonzo75

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Feb 26, 2014
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#37
Interesting. I was hoping you would reply as I figured you have compared them.
With Allnic I would like to compare elrog, acme (people have done these compares in Lampi but not in Allnic) and WE 274b to the RK
 
May 3, 2017
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#38
I ordered the KR RK 5U4G. The Allnic H3000 I bought has the Tung Sol installed so that will be the only ones I compare. Someday when I'm bored I will order a few more to compare.
 

dminches

Well-Known Member
Oct 22, 2011
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#40
I have the RK KR 5U4G and the Psvane Acme 274B. Both are great. I have not compared them critically yet though...
Have you compared any to old stock Tung-Sols, Raytheons or Sylvanias?
 

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