Clark Beauford makes strange noise

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by voodoohound, Feb 19, 2009.


  1. voodoohound

    voodoohound Member

    Messages:
    11
    Joined:
    Dec 21, 2006
    Location:
    Close to Munich - Bavaria - Germany
    Could you please try to help me solve an amp problem I have with my Clark Beauford 5E3 Deluxe?

    Whenever I hit a louder note there is an ugly distorted tone - it sounds like the blue Celestion speaker is farting out.
    I hooked up another well working speaker instead but it did not go away.
    I changed all tubes with exception of the rectifier tube - nothing changed.
    Do you have any idea what this could be? When I play very soft, the sound is OK. But whenever I play harder, the amp has this squealing distortion.
    Thank you very much!!!!
     
  2. wyatt

    wyatt Member

    Messages:
    4,081
    Joined:
    Oct 11, 2005
    A few things, but I would check that rectifier.

    Tube rectifiers are very inefficient, it takes them awhile to supply the power demanded of them when called upon, the more the demand, the harder they have to work. That's the source of "sag." I suspect that your rectifier is buckling under when called to really supply power.
     
  3. CADdrafter

    CADdrafter Senior Member

    Messages:
    559
    Joined:
    Jun 23, 2006
    agreed. i would try a quality recto tube as my next step.
     
  4. voodoohound

    voodoohound Member

    Messages:
    11
    Joined:
    Dec 21, 2006
    Location:
    Close to Munich - Bavaria - Germany
    Thank you very much - that sounds logical. Unfortunately I do not have a spare 5Y3 rectifier. Is it possible to use a GZ34 instead for a test?
     
  5. CADdrafter

    CADdrafter Senior Member

    Messages:
    559
    Joined:
    Jun 23, 2006

    i would visit Clark's site to make certain but i THINK you can.
     
  6. wyatt

    wyatt Member

    Messages:
    4,081
    Joined:
    Oct 11, 2005
    There should be little problems in testing it with the GZ34, but I wouldn't run it in there as a long-term substitute.

    Well, if you were using a NOS 5Y3, then a GZ34 will significantly increase B+ voltage and may make the power tubes run too hot. Which could result in other sonic issues that can confuse the issue.

    If you've been using a Sovtek 5Y3, then you might as well pop in the GC34, because that's pretty much what you've been running anyway, of course, that could then be part of the problem. Sovtek 5Y3's don't have the same voltage drop as a NOS 5Y3, the Sovteks tend to keep the voltages 40VDC higher, which doesn;t work well with vintage-value cathode bias caps/resistors.
     
  7. CADdrafter

    CADdrafter Senior Member

    Messages:
    559
    Joined:
    Jun 23, 2006
    taken from the Clark Amp's site:

    Voltage corrected power and custom wound output transformer. No harsh high voltages. However, if you want to get the tone of an older overvoltaged 5E3 you can use a 5V4 or 5AR4 rectifier to get the plates up to that level.
     
  8. voodoohound

    voodoohound Member

    Messages:
    11
    Joined:
    Dec 21, 2006
    Location:
    Close to Munich - Bavaria - Germany
    What I have installed is a Philco 5Y3GT - made in USA - rectifier tube. I will pop in a Mullard GZ34, rebias and see what happens, talk to you soon....
     
  9. CADdrafter

    CADdrafter Senior Member

    Messages:
    559
    Joined:
    Jun 23, 2006
    shouldn't have to rebias as this amp is cathode biased....
     
  10. voodoohound

    voodoohound Member

    Messages:
    11
    Joined:
    Dec 21, 2006
    Location:
    Close to Munich - Bavaria - Germany
    ..shame on me, I should better use my brain - it's class A:jo
     
  11. CADdrafter

    CADdrafter Senior Member

    Messages:
    559
    Joined:
    Jun 23, 2006
    :aok:
     
  12. voodoohound

    voodoohound Member

    Messages:
    11
    Joined:
    Dec 21, 2006
    Location:
    Close to Munich - Bavaria - Germany
    It seems to be a little bit better with the GZ34 but the noise is still there when playing loud. I also checked for cabinat buzz.
    I will one more time change all tubes and see what happens - thank you again for your time and help
     
  13. Bloozman

    Bloozman Member

    Messages:
    435
    Joined:
    Feb 26, 2006
    It might be bad solder joint at a tube socket. I had the same problem with a 65 Tremolux, especially when hitting low notes. Check that out!
     

Share This Page