WA6 Tube Rolling

Discussion in 'Headphone Amps (full-size)' started by mamma, Apr 15, 2007.
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  1. wovenhand
    So, I went for the GZ34 Philips/Mullard and the 5U4G Sylvania. He only had 2 vs 1 of those in stock and I felt I'm already waaa-ay over budget with the purchase of the HP-DX1000's, so I'll go for the 5R4GYB Sylvania's the next time I order as he had like 6 of those in stock.

    Hopefully I'll have em tomorrow, so this should be fun. I hope. [​IMG]
     
  2. wovenhand
    Okay, I got em and a quick first impression was that the Philips GZ34 sounds pretty much exactly like my Mullard 5AR4 (which I kinda expected), only with a slightly lower output.
    The Sylvania 5U4G sounded as it looked - empty. The mids where not as upfront as the Mullard/Philips and overall it was just less engaging.
    It's got the code "E5M".. anybody who can translate..?

    N00b questions:
    Does the lower output of the GZ34 mean it's in less than stellar condition or is it simply a different design which delivers lower output?
    Is there any major difference between the GZ34 and 5AR4..? These two look 95% alike in design.

    And lastly, I know how to decipher the last 4 digits of the stamped code, but what does the "f32" stand for?
    Also, is there some way to see which decade the 2nd digit (most likely) represents, if it's made in the 50's/60's/70's/etc?

    I'm sure these questions have been asked before, but my searches did not deliver the answers I was looking for.
     
  3. takezo
    the gz34 is english designation and 5ar4 is american... same tube
    made almost exclusively by mullard but rebranded... mullard bought
    out philips in the 50's i believe... early metal base are all philips.

    the lower output is probably due to early versus later design and
    of course a good tube versus a tube in its last days...

    the fxx is part of mullards date code. f31 is designating the earliest
    version of the gz34 series... f32, f33 came later in the early 60's
    and 70's i believe. you can also tell by the getters, a round and
    a "D" shaped getter... some say the "D" is earlier, but i've found
    early 50's mullard with round getters...

    all the metal base, fat base gz34/5ar4 are f31 of the early 50's.
    to be more specific, the metal base are rsb for 1951 (earliest that
    i know of), rs1 for mid 50's, and tv2 for late 50's. all metal base
    is from einhdhoven, holland. regardless of branding.
     
  4. wovenhand
    Thanks takezo, I really appreciate your thorough answers. [​IMG]

    Both mine read f32, so I guess one can assume they're from the 60's then..?
    And both have round getters. And regarding the lower output, they both sound great - the Philips (B3A2) just has a little bit lower output compared to the Mullard (B7A5).
    The one I got today (Philips) is NOS (and looks to be in a lot better shape cosmetically than my Mullard), but I sadly have no way to test it. The dealer has a good rep though, so I have no reason to doubt him.
    Besides, most Swedish folk are usally solid good-guys. [​IMG]
     
  5. takezo
    you're welcome wovenhand.

    even good people can sell valves that arrive bad... you should
    invest in a good tube tester if you intend to keep your tube amp
    away from a shorted tube... you don't need a $1000 tester, just
    a good functioning emission tester for around $100...
     
  6. Golden Monkey
    Hey guys, don't mean to butt in on the WA6 thread, but is there a tuberolling thread for the WA3+? I searched, but didn't find a specific one.
     
  7. takezo
    sorry, don't know of one... jamato8 may know.
     
  8. jamato8 Contributor
    Quote:

    Originally Posted by Golden Monkey /img/forum/go_quote.gif
    Hey guys, don't mean to butt in on the WA6 thread, but is there a tuberolling thread for the WA3+? I searched, but didn't find a specific one.



    There is mention of different tubes on my thread where I modified the Woo 3.
     
  9. jamato8 Contributor
    Quote:

    Originally Posted by takezo /img/forum/go_quote.gif
    you're welcome wovenhand.

    even good people can sell valves that arrive bad... you should
    invest in a good tube tester if you intend to keep your tube amp
    away from a shorted tube... you don't need a $1000 tester, just
    a good functioning emission tester for around $100...




    Not to disagree with you too much but I would not use an emission tester. Many of them apply the incorrect voltage and can damage a tube. They are one of the worst things for tubes. There have been a number of articles about them and one goes into length on the damage to be done. They can be googled.

    The Hickok testers, most military testers, AVO's and other good testers use mutual conductance and a few other methods that give you a value but apply voltages in the correct manner.
     
  10. wovenhand
    Quote:

    Originally Posted by takezo /img/forum/go_quote.gif
    you don't need a $1000 tester, just
    a good functioning emission tester for around $100...




    You got a good tip for which tester(s) to seek out..?
    I really have zero idea what brands/models are considered good when it comes to this.
    And my wallet is right now crying in a corner, so like you pointed out,
    nothing fancy but a good solid emission tester would do nicely.
    Thanks again for helping out!
     
  11. wovenhand
    Okay, I saw jamato8's reply, so I rephrase [​IMG] What's the cheapest I can get away with but still have a solid reliable tester? Brand/model suggestions, anyone?
     
  12. Golden Monkey
    Quote:

    Originally Posted by jamato8 /img/forum/go_quote.gif
    There is mention of different tubes on my thread where I modified the Woo 3.



    Cool, thanks jamato. That's the thread that lit the fire of my tubey desire, lol...
     
  13. jamato8 Contributor
    Hickok, the military TV7 B or C or D or E but not A. I would get a tester that has been calibrated or a good working one cheap enough and have it calibrated or checked by someone who know testers and check it for accuracy. You then need time to learn about the tester. Understanding them just takes time and you learn what the readings mean.
     
  14. wovenhand
    Thanks jamato!
    Yeah, I kinda figured I couldn't just plug it in and hope for the best, hehe.
    If I still had lived back in my hometown I could've approached several guys for a tutorial, but now I'm out in the middle of nowhere so I guess the internets will have to be my teacher.
     
  15. jamato8 Contributor
    It was just time, reading and using a tester that taught me. Even in the navy as a radioman (we used tubes now there aren't radiomen) I don't remember a tester being used. If a tube went out you just grabbed a new one but many times it was the circuit that went bad and took the tube out. I wish I had grabbed some of those fine tubes. I read of a guy on the east coast that somehow knew tubes were worth keeping and whenever he went to a swap meet or TV store going out of business he would get all the tubes. He had a few million in storage in a barn. I have no idea what has become of them.
     
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