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Strange buzz from my Yorkville BM400 115 combo

Discussion in 'Amps and Cabs [BG]' started by fourstringbliss, Mar 26, 2009.


  1. fourstringbliss

    fourstringbliss Supporting Member

    Oct 5, 2003
    Puyallup, WA
    I'm getting a thin, paper-like buzz from my Yorkville BM400 when I play the B, C, and C# on the A string, but not when I play any other note.

    What's up with that?
     
  2. MIJ-VI

    MIJ-VI Banned Supporting Member

    Jan 12, 2009
    Can you isolate the buzz to the speaker, or to the cabinet?

    If it's coming from the cabinet, it could be a loose layer of plywood.

    After your recent installation of casters (one of their ball bearings etc may be vibrating), did you remove any frayed wood from the edges of the holes you drilled?

    Or perhaps the noise source is a small electronic component in the head of your amp which is touching one of its neighbors and vibrating in resonance with the played notes that you mentioned.

    Are there any loose screws anywhere on the amp?
     
  3. MIJ-VI

    MIJ-VI Banned Supporting Member

    Jan 12, 2009
    If the speaker won't budge, then its contact with your amp's cabinet likely isn't the noise source.
     
  4. fourstringbliss

    fourstringbliss Supporting Member

    Oct 5, 2003
    Puyallup, WA
    I think we might be narrowing things down here. It's possible that I've got bits of wood sticking up from screw holes. It's also possible that I screwed into the end of a piece of plywood and that raised something.

    Is it possible that this is caused by sawdust?
     
  5. fourstringbliss

    fourstringbliss Supporting Member

    Oct 5, 2003
    Puyallup, WA
    I'm definitely going to pull the speaker out and make sure there's nothing loose inside. I'm also going to tighten all of the screws.
     
  6. MIJ-VI

    MIJ-VI Banned Supporting Member

    Jan 12, 2009
    "Is it possible that this is caused by sawdust?" It's more likely to be splinters if wood is the source of the buzzing sound when certain notes are played. That said, vacuuming out any debris would be a good idea.

    Also, examine the glue joints on the speaker's dust cap for possible separation, and the driver's surround for fatigue cracks.

    --------

    If the buzzing sound is still present in spite of your efforts re the cabinet and speaker, try to isolate its source by boosting the BASS control and cutting the remaining EQ so you can trouble-shoot the buzzing without going deaf. :)

    If its source remains elusive, then perhaps removing the amp section of your combo to examine it for touching electrical components would be an idea.

    As well, you could then eliminate (or confirm) the amp's chassis as the noise source by playing through your combo's speaker while the amplifier section is separated from the cabinet.
     
  7. fourstringbliss

    fourstringbliss Supporting Member

    Oct 5, 2003
    Puyallup, WA
    I'll try those things. It began after I installed the casters, so I'm sure it's a piece of plywood or one of the caster bearings, or something like that.

    Thanks for the suggestions!
     
  8. MIJ-VI

    MIJ-VI Banned Supporting Member

    Jan 12, 2009
    :eek: Oh no! It's the the caster conspiracy! :D
     
  9. fourstringbliss

    fourstringbliss Supporting Member

    Oct 5, 2003
    Puyallup, WA
    It looks like the buzz was something in the room. I played out with the amp this weekend and got no buzz.

    Thanks for the suggestions - I'm glad it turned out to be nothing!
     
  10. MIJ-VI

    MIJ-VI Banned Supporting Member

    Jan 12, 2009
    Good! :)
     

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