Eden toroidal transformer buzz

Discussion in 'Amps and Cabs [BG]' started by slareman, Dec 28, 2007.

  1. slareman


    Nov 7, 2007
    Alright, I will take it to a tech. It's really too bad that I don't have a backup amp, though. Thanks a lot for all the help, bassmodder!
  2. Yeah no problem. My "backup" amp got "installed" in our main pa setup because the crown took a lightening hit. So I always get to lug my 60 lb Ampeg around:(

    I am thinking I want my amp back.

    Good luck with the repair and nice Job with sticking with it and doing all you could.
  3. BassmanPaul

    BassmanPaul Inactive

    Nobody has asked so I will. You say your amp is 'Upgraded" to WT400 specs. Just what were the modifications and who did them? Did the amp hum before the mods were done or only after?

  4. slareman


    Nov 7, 2007
    I bought the amp after it had been upgraded...the former owner said it was sent to the Eden factory (you can see of list of the upgrades that Eden will perform on their website). I haven't been able to confirm this, but the power amp board is a different color than the other boards in there and it says "PM400" on it. Also, the gain and enhance knobs are push/pull, which I believe wasn't the case for the stock WT-300.
  5. BassmanPaul

    BassmanPaul Inactive

    You said that you were advised to try rotating the toroid and when you tried the hum got much worse. Did you rotate it back to its original position?

  6. slareman


    Nov 7, 2007
    After I moved it the first time, the noise just stayed worse—even when I moved it back to the original position.
  7. Where are the power connections to the transformer in relation to the preamp board? It sounds like you're getting induced line noise from something not properly physically routed.
  8. greenboy


    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Hi! I'm your friendly amp technician! I live perhaps thousands of miles outside the range of hearing and seeing your amp - even when it's turned up and working! So I've devised this handy questionnaire! In order to help me more efficiently diagnose and repair the problem with your amplifier please respond to the following points:


    1. Describe your problem:

    2. Now, describe your problem accurately:

    3. Speculate wildly based on faulty knowledge about almost everything
    just what's the cause of your problem:

    4. Please indicate the severity of your problem:
    A. Minor___ B. Minor___ C. Minor___ D. Trivial___

    5. Nature of problem:
    A. Sounds bad___ B. Sounds really bad___ C. No sound___
    D. Strange smell___ E. Smells really bad twice___

    6. Was your amp plugged in?
    Yes___ No___

    7. Was it turned on?
    Yes___ No___

    8. Did you try to fix it yourself?
    Yes___ No___

    9. If so, did you make it worse?
    Yes___ Yes___

    10. Did you have a "friend" who "knows all about amps" try to fix it for you?
    Yes___ No___

    11. If so, did they make it worse?

    12. Have you read your manual?
    No___ No___

    13. Are you sure you've read the manual?
    Maybe___ No___

    14. Are you absolutely SURE you read the manual?
    No___ I was going to...___

    15. If you DID read the manual, do you think you UNDERSTOOD it?
    Yes___ No___

    16. If yes, explain why you can't fix the problem yourself:

    17. What were you doing to your amplifier at the time the problem occurred?

    18. If you answered "nothing", explain why you think there's a problem:

    19. Are you sure you're not imagining the problem?
    Yes___ No___

    20. Does the clock on your DVD player always blink 12:00?
    Yes___ That's a clock?___ What's a DVD?___

    21. Do you have any electronic devices that DO work?
    Yes___ No___

    22. Do you have an independent witness to the problem?
    (Does not include drummers)
    Yes___ No___

    23. Have you given the amplifier a good whack on top?
    Yes___ No___

    24. Did the amplifier catch fire?
    Yes___ Not yet___

    25. Do you have another amp you can use while you wait to take this one
    to a repair shop like you should have done in the first place?
    Yes___ No, I prefer to be out of commission longer___

    26. Has the foam inside your speaker cabinet caught fire repeatedly?
    Yes___ No___ What's a "cabinet"?___

    27. Has the foam inside your speaker BOX caught fire repeatedly?
    Yes___ No___

    28. If so, did you replace it with an approved dampener?
    No. Enough beer gets spilled in there to keep it safe___
    No. The cat's always whizzing in there after a good scratch on the carpet anyway___

    28. Let me restate this: If so, did you replace it with an approved DAMPING material?
    No. My drummer used all the egg cartons inside his kick drum instead. ___
  9. slareman


    Nov 7, 2007
    The preamp board sits in the front; the knobs on the front panel are on the preamp board. It is connected to the filter cap section via a cable with a single connector. The transformer has a few wires connected to the rear panel of the amp, and a few connected to the filter cap section (which is also at the rear of the amp, but extends to the middle).
  10. Without having the amp in front of me, layout or ground issues are nearly impossible to diagnose. Aside from your attempted self-repair, has an actual tech ever had ahold of your amp to fix this problem?
  11. slareman


    Nov 7, 2007
    Nope, that's the plan for tomorrow ;) Thanks.
  12. Ok, keep us posted!
  13. bthrem


    Dec 4, 2005
    Cincinnati, OH
    Following up on my similar post:


    I found the source of my issue to be the green ground wire that comes off the effects loop / DI / etc connector on the preamp board. As I moved it around within the amp, the buzz in the output signal would become intense to nearly non-existent. It seems this wire is very susceptible to various electric fields generated within the amp. I found an optimal location and taped it in place. All is well now.
  14. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

    Sep 20, 2021

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