Subwoofer intermittently hums loudly

Discussion in 'Archived Threads 2001-2004' started by Walter_M, Mar 18, 2002.

  1. Walter_M

    Walter_M Extra

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    My subwoofer has suddenly taken to intermittently humming loudly, but other than that, it appears to work fine.

    The humming initially started whenever my 5-year-old son would jump from the sofa to the floor (something he’s inclined to do despite his parents’ admonitions). The subwoofer is located behind the sofa, and it appeared that mechanical vibration would set it off. I can always make it stop humming by simply touching with my finger the metal where the RCA signal line plugs into the back of the subwoofer.

    Now the problem has grown worse, with the subwoofer suddenly humming without apparent provocation (it’s loud enough to wake us up at night). Again, I can always make it immediately stop humming by simply touching with my finger the metal contact of the RCA signal line.

    The subwoofer is a Yamaha YST-SW105 Active Servo Processing Subwoofer System. It’s about 6 months old.

    Any suggestions?
     
  2. ColinM

    ColinM Cinematographer

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    Cable swap.

    Worked for me once.

    Good luck!
     
  3. John Desmond

    John Desmond Stunt Coordinator

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    I'm betting it is either the cable or the input jack. I'd go with Colin and swap cables first. IF that doesn't do it, it is likely the RCA input jack cracked solder joint.
     
  4. ColinM

    ColinM Cinematographer

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    In my case it was as if static was building up, and then *boop*, gone. As if it discharged. I was worried that a capacitor was going or something. (In the sub amp)
    The hum level came up from nowhere slowly, and got louder over time, say 5 minutes or so. Annoyingly loud occasionally.
    The cable swap did the trick, but less than a week later I swapped AVR's as well. A month later the sub was replaced.
    Great hobby...[​IMG]
     
  5. Walter_M

    Walter_M Extra

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    Yuck. I suppose it's the cable--when I disconnect it from the subwoofer, the hum stops. It's 30 ft. of cable though--two 15 footers with a gold connector in between. Weren't cheap either. They run under the livingroom floor through a crawl space. Don't know why they're suddenly misbehaving after 6 months of trouble-free performance, unless maybe the weight of the cable itself has pulled a connector loose. Okay, I'll swap the cables. Yuck.

    Thanks for all the feedback folks.
     
  6. ColinM

    ColinM Cinematographer

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    Save the receipt!
     
  7. Wayne Ernst

    Wayne Ernst Cinematographer

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  8. Walter_M

    Walter_M Extra

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    Hi Wayne,

    Thank you for your tip. You say: "purchase a 20 foot RCA gold interconnect cable. Separate the two sections of the new cable and re-use your existing connetor to bridge the new cables", I assume you mean that I should replace one of my (two) cable lengths to the subwoofer? Or do you mean something else?

    I currently have two Radio Shack gold cables running to the subwoofer (composed either of two 15 footers or a 20 + 10 footer--I forget exactly which).

    If it's only a matter of replacing a bum cable, I guess I should be greatful, however I still don't understand why a cable should fail if it's not under any dynamic mechanical stress.
     
  9. ColinM

    ColinM Cinematographer

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    Poor sheilding, lack of proper connection, poor build quality, bad solder job.

    Hit and miss, kind of a phenomenon.
     
  10. Wayne Ernst

    Wayne Ernst Cinematographer

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    Walter,

    Sorry it has taken so long for me to respond. Allow me to clarify what I've done in the past. I've purchased one 20' gold interconnect cable for $19.99 at Radio Shack. I separated the cable to make 2 individual 20' lengths. I then connected two of the ends together with a RCA coupler to make a single 40' cable. It sounds like you already have the coupler from your old cable connection, so the cable is all you'd need. Please let me know if you have any additional questions.
     

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