Cause of blown speaker

Discussion in 'Amps and Cabs [BG]' started by gbrooding, Feb 28, 2016.


  1. gbrooding

    gbrooding

    Dec 22, 2011
    Situation: Fender Bassman 100 solid state combo amp. MXR Octave pedal (not using battery, using adaptor), G&L L-1500 bass. I plugged everything in, turn amp on with bass volume off, and the amp makes a loud rumble noise and I see the speaker bouncing hard up and down. I unplug the cable going into the amp, and it stops. I am at a complete loss as to what to even look for. The speaker is toast, but I want to find the problem to make sure it doesn't happen again. Any suggestions would be appreciated!

    Thanks,
    Greg
     
  2. Octave pedal.
     
  3. Shouldn't have blown with the bass volume off. Suspect user error in that regard.
     
  4. gbrooding

    gbrooding

    Dec 22, 2011
    The user error being?
     
  5. Volume not off.
     
  6. gbrooding

    gbrooding

    Dec 22, 2011
    Thing is the volume on the bass guitar was off.
     
  7. beans-on-toast

    beans-on-toast

    Aug 7, 2008
    Too much volume and or too much bass are often culprits. External pedals can drive an amp hard. An oscillation in a circuit is another possibility.
     
  8. gbrooding

    gbrooding

    Dec 22, 2011
    a faulty pedal?
     
  9. Octave below low A has potential to give wild excursions at low power.
     
    bassmeknik, bmxican33 and tfer like this.
  10. gbrooding

    gbrooding

    Dec 22, 2011
    When all of this happened I was not playing the bass at all.
     
  11. /\/\3phist0

    /\/\3phist0 ( ͡° ͜ʖ ͡°) mmm Woody! DHDIK?

    Bad cable, partially inserted cable, adapter wrong polarity causing burst of noise.

    Where was the amplifier's gain/ master set?
    Where was the pedal inserted? Effects loop? Or in front if amp?

    The only thing that conceivably could have caused this would be TOO MUCH POWER SENT TO THE SPEAKER. So the master was dimed right?
     
    skychief, SunnBass and squidtastic like this.
  12. B-string

    B-string Supporting Member

    Check your wall wart pedal power pack. If you got one the outputs AC voltage instead of 9VDC, there is your cause.
     
    SunnBass and squidtastic like this.
  13. gbrooding

    gbrooding

    Dec 22, 2011
    the Amps gain was at 4 and the master at 5. Only pedal used was an octave pedal. Bass to pedal to amp.
     
  14. If the bass volume was up at all there may have been feedback of sub frequency. If the overtones from the speaker were strong enough to keep the octave generating more sub, boom. Or carrots.
     
  15. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    I understood Greg's post. I don't think there's anything tricky about it.

    This is a weird one, though. By all rights, it shouldn't have happened, yet it did. I don't know that a BOD is a strong enough force to where it could cause your amp to go into some sort of weird oscillation mode when the volume of your bass is turned down. I've plugged one into an amp several times and turned it on and it's never caused any problems. I'm thinking your amp chose that particular time to go on the fritz, Greg, but it's really hard to know without being there, especially with all the info you've given us...assuming you're not BSing us and leaving out something very important :D
     
  16. gbrooding

    gbrooding

    Dec 22, 2011
    Yeah I've tried to write out everything that I knew happened and the order of events. I am relatively inexperienced in the technical aspects of what could have happened. Last thing I want to do is bs anyone! I am just trying to figure out/isolate the problem so it doesn't happen again. I have had the amp for around 15 years. .. no problem. The octave pedal around a year. .. no problem. The bass a week. It is a G&L L-1500. I can't think of anything else that might be important?
     
  17. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    An amp you've had for 15 years with no problem? Well there's the answer...you're overdue! I'd definitely bet on it being something in the amp causing an oscillation knowing that. Of course, if you plug that bass and BOD into another amp and smoke it, too, I am wrong. But I doubt you will. Have you tried it elsewhere yet?
     
  18. gbrooding

    gbrooding

    Dec 22, 2011
    Yes I've played the bass with and without the pedal on three different rigs since then with no issues. (Nervous each time I might add). Also added the scr-di just to see how that sounded. No problems at all.
     
  19. gbrooding

    gbrooding

    Dec 22, 2011
    Appreciate all the input and help!
     
  20. rufus.K

    rufus.K

    Oct 18, 2015
    SoCal
    But not the amp volume. Maybe jack or cable created a short at input.
     
    Jim Carr, mbelue and /\/\3phist0 like this.
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