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Question about minimum safe load

Discussion in 'Amps and Cabs [BG]' started by black4string, Apr 9, 2006.


  1. I have read in one of the posts here, that you could damage your amplifier if you run it below the minimum safe load.

    Someone borrowed my combo amp and opened it up to attatch another speaker.
    He said, "so it'll be louder".
    But after a few notes, suddenly, there was nothing but ground from the amp.

    Is the ground a symptom of a damaged amp?
    if so, how can this be fixed?
    I'm a little short on money to get it fixed at fender..
    thanks
     
  2. Kael

    Kael

    Dec 26, 2004
    Oklahoma City
    Sounds like bad stuff has happened. No worries though. Unless you authorized the person who borrowed your amp to do that "mod" work, then they are responsible (legally) for fixing it.
     
  3. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    I don't know what that means. You mean a 60hz hum? Silence?

    It sure sounds like the power section was damaged (output power transistors and/or power supply) by expecting them to flow too much current (output load impedance too low).
     
  4. Groundloop

    Groundloop

    Jun 21, 2005
    Toronto
    I think it's safe to say that "someone" did damage to your amp, and that "someone" is responsible for fixing it.

    Having to open the amp up to attach another speaker indicates that the combo was never designed to have another speaker attached, most likely because the speaker(s) were already matched to the minimum safe load for the amplifier.

    And, IMO, "someone" is a d*ck.
     
  5. Kael

    Kael

    Dec 26, 2004
    Oklahoma City
    I disagree with this statement. That isn't your opinion, but a verifiable fact.
     
  6. georgestrings

    georgestrings Banned

    Nov 5, 2005

    +1 on ALL of the above... Generally speaking, if a combo doesn't have a jack for an external speaker, it probably can't support one - unless you're smart enough to match impedence with the original speaker...



    - georgestrings
     
  7. Groundloop

    Groundloop

    Jun 21, 2005
    Toronto
    Thanks for the backup Kael.

    Being Canadian, I didn't want to seem too pushy.
     
  8. So i'll check the power supply and the output transistors?
     
  9. the ground i'm saying is like when you touch the tip of your cord. then it makes the buzzing sound.

    but the amp only produces the ground, even if i connect a guitar or turn the dials way down or way up.

    thanks for the replies
     
  10. This is why you should never trust anyone with your gear ever.
     
  11. Trevorus

    Trevorus

    Oct 18, 2002
    Urbana, IL
    Yeah, bad idea to let someone open up the amp to mod it. I do my own mods to my stuff, but I have experience. Kick that guy in the nuts. (after he fixes it, of course)
     
  12. lesson learned, thanks guys.
     
  13. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Really? I thought being Canadian was pretty much like being French.
     
  14. dharma

    dharma Srubby wubbly

    Oct 14, 2005
    Monroe, Louisiana
    Being Canadian is a lot like being Jim Carey, Alanis Morissette or Mike Myers.
     
  15. jondog

    jondog

    Mar 14, 2002
    NYC metro area
    No, you shouldn't check anything. "Someone" should take the amp to a repair tech and pay to have it fixed. Then he should return it to you and say sorry. If he refuses tell his mom and she'll do it.
     
  16. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    If you have the equipment and expertise ..... my diagnosis was a pretty general thing, about like saying '... it's the motor allright'.

    The symptoms you describe don't sound like that's necesarily the problem; I would expect complete silence. That 'buzz' you hear is 60hz AC from the power supply getting amplified (but at least something is getting amplified). Depending on the model you will probably find that the parts cost much less than the labor to diagnose and replace them. And your pal should pay for it.
     
  17. If you didn't know enough NOT to let that idiot hack your amp apart and tear it up, you certainly don't have the expertise to repair it.
     
  18. Which part exactly? Power supply?
     
  19. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    No one can diagnose this across the Internet.

    From the questions you have been asking, I don't think you are qualified to attempt a repair yourself and you are only likely to cause more damage.

    Not trying to be snotty, but you have ignored more subtle approaches.
     
  20. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    OK, two out of three ain't bad, I guess.
     

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