Tubes Asylum

Posted by REL54 (A) on April 30, 2007 at 15:24:42

In Reply to: Questions regarding rectifier tubes??? posted by acours on April 30, 2007 at 01:09:08:

the 5R4 max cathode current is 650 ma and the 5U4G's is 800ma. The 5R4's PIV is 2800v whereas the 5U4G's is 1550v. The 5R4's voltage drop at 250ma is 67 volts but the 5U4G's is 44 volts at 225ma.

this stuff is all easy to find at:
http://tdsl.duncanamps.com/

not trying to be a smarta** or anything, but why do you need current production stuff when actual NOS RCA's or GE's or Sylvania 5Ur's are dirt cheap? Are you just curious?

I was curious about the current production 5AR4's and so I bought a quad of the JJ/Tesla ones just to see how they stacked up against the Mullards that I have. They're actually pretty good.

I never thought about the current production 5U4 tubes. If you get some, give us a report about how they sound, look, build quality, etc. thanks in advance,
roN

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• Current Production 5U4s - Eli Duttman 16:08:10 04/30/07 (3)
  In Reply to: Re: Questions regarding rectifier tubes??? posted by REL54 on April 30, 2007 at 15:24:42:

  Current production Chinese and Russian 5U4Gs are GUANO.

  The only current production 5U4 that might be acceptable is the Russian 5U4GB, which come on stream a couple of years ago.

  The recommendation to buy US made NOS is CORRECT. TungSol, RCA, and GE 5U4GBs are still affordable, good sounding, and long lasting.
  
  Eli D.
  
  

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  • you are certainly right about - REL54 15:42:40 05/01/07 (1)
    In Reply to: Current Production 5U4s posted by Eli Duttman on April 30, 2007 at 16:08:10:

    all of that, especially the long lasting part. I have a GE floor radio (H-87) that uses two 5U4's in the power supply. The thing used to STAY on all the time at my grandparents house. Those tubes have 10,000+ hours on them and they still test strong.

    I think if a tube guy buys a few 5U4's (oh, say 10 or 12) he will likely have a life time supply. I recommend RCA's or Sylvanias.

    Mullard 5AR4's last forever too. I have the old Bogen M60 PA amp that we used to use in our church. Only God knows how many hours are on those original Mullard 5AR4's but they still are strong testing tubes.

    gotta love em

    roN
    
    

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    • Re: you are certainly right about - Eli Duttman 18:05:37 05/01/07 (0)
      In Reply to: you are certainly right about posted by REL54 on May 1, 2007 at 15:42:40:

      20+ years of HARD service is common with Mullard made GZ34/5AR4 rectifiers.
      
      Eli D.
      
      

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  • Used stock is likely to have plenty of life left too. - JJ Triode 23:04:28 04/30/07 (0)
    In Reply to: Current Production 5U4s posted by Eli Duttman on April 30, 2007 at 16:08:10:

    These are very rugged tubes. I got some used RCA 5R4GY brown base ST's for $5 each, they work fine.
    
    

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