My Sunfire True Sub Won't Stop Humming!!!

Discussion in 'Speakers' started by Seth=L, Jul 22, 2006.

  1. Seth=L

    Seth=L Screenwriter

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    I have tried everything I can think of with this thing. I have tried grounding it, moving the sub cable away from the ac lines, I've tried changing the polarity of the ac input, and I tried moving the sub to another outlet.
    Someone please help, this thing is driving me up the wall!
    Thank you in advance,
    Seth=L
     
  2. Seth=L

    Seth=L Screenwriter

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    Is it even possible to ground this sub, It doesn't have any external metal other that the screws.
     
  3. Cees Alons

    Cees Alons Moderator
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    Seth,

    Does it also hum when no input is attached at all? In that case, it's the sub.

    Normally you won't need to ground the sub or a shield around the sub in an extra way.

    If it only hums when an input lead is connected, it may be a ground problem. Does the sub use the same power outlet as the amplifiers (receiver) do (does)? Preferably it should.

    Also, did you try connecting the sub's connection cable (output from amp/receiver) to another (spare) amp (TV or something)? Sounds terrible, but if that one hums too, it may be the cable and/or the receiver output.

    Cees

    PS : I moved this post to 'Speakers and Subwoofers', where it may attract more attention.

    C.
     
  4. mylan

    mylan Screenwriter

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    I had this problem with mine once, it was a bad cable.
     
  5. RussD

    RussD Agent

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    Seth,

    My true sub had a hum problem also. My dealer recommended a solution which has worked well (no more hum) but goes against all safety rules and i'm sure is backed by none at "home theater forum". Cheater plug. I've used it for 4 years now. No humming, but use at your own risk.
     
  6. Seth=L

    Seth=L Screenwriter

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    Thank you for the info and for moving the post. Is there any way for me to select how the thread is categorized or is this done automatically?
     
  7. Seth=L

    Seth=L Screenwriter

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    I tried plugging it in to the same outlet as the receiver, still hums. I tried using another cable, still hums. Tried plugging it into the television, still hums. When the subwoofer is plugged in but not terminated with any connection it does not hum, when I plug the sub cable in wiht no termination at the other end it does not hum, but as soon as I plug it at the source, it hums (even if the receiver is off or even unplugged it will still hum).
    I feel dumb for asking this but what is a cheater plug?
    My sub has a 2 prong non-polarized plug. no ground.
    Seth=L
     
  8. mylan

    mylan Screenwriter

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    I find that odd that your sub only has 2 prongs but I believe you, really. A cheater plug is an adapter that has a female three prong plug on one end (that you would plug the sub into) and a two prong male plug on the other. It works but defeats the purpose. There was another thread running around here where the guy used a cheater plug and lightning blew his SVS out.

    I did a few tests with my Velo at my old house once. The sub would turn itself on when another device on the same circuit was powered on, causing it to hum slightly. I ran an extension cord down the hall to another room and it went away. I had to replace the outlet then. I thought sure changing the cable would work, it did in my case. Hmm????
     
  9. Seth=L

    Seth=L Screenwriter

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    My sub is first-gen so it is not detachable (much to my dissmay). The sub doesn't start humming untill after it is fed some source material. after which it will only stop if I unplug the sub or diconnect it from the source.
    Seth=L
     
  10. mylan

    mylan Screenwriter

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    Is it a loud hum or just perceptable? Is it accompanied by distortion? Does the driver move alot or seem to vibrate? I am no expert but perhaps the amp has gone bad?
     
  11. Seth=L

    Seth=L Screenwriter

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    no the amp is probably OK. The hum is very quiet, but like a mosquito buzzing in your ear it is very annoying.
    Seth=L
     
  12. mylan

    mylan Screenwriter

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    Just my 2 cents without actually listening to it, it is probably operating normally then. You might have the gain (volume) up too high.

    My Velodyne HGS 10 is of the same design; sealed enclosure, high wattage amp, large driver with high excursion, and sometimes in idle I am aware that it is on but I do have to be close to hear it. Other than that,i'm going to step aside and let the real experts here try to help.
     
  13. Seth=L

    Seth=L Screenwriter

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    Yeah unfortunitly that's not it either even with the gain all the way down it still hums. I think this is a common problem with subs that use direct ac current these subs don't have power transformer (other than the control's transformer). I live at apartments maybe I need a power cleaner.
    Seth=L
     
  14. mylan

    mylan Screenwriter

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    Yes, I seem to remember using a Monster power conditioner strip as well in my old house. I had everything else connected to a Panamax. What is probably happening is the sub is set to "auto sense" and turns on when it senses a signal but will also turn itself on whenever there is a power surge from some other appliance or EMI/RF interference down the line somewhere. I would just turn the sub on when needed.
     
  15. Seth=L

    Seth=L Screenwriter

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    That sadly isn't an option the only way to shut it completely off is to unplug it and when I do the capacitors release their stored energy and the sub makes a loud noise. The auto detect is a stationary function that can't be switched off. As I said before it is first gen very primitive.
    Seth=L
     
  16. mylan

    mylan Screenwriter

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    Sounds like it is time to move up to an SVS![​IMG]
     
  17. Arthur S

    Arthur S Cinematographer

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    Seth

    I recall the review of the original Sunfire sub from years ago. I'm talking at least 10 years ago and maybe quite a bit farther back than that.

    The reviewer mentioned that they had humming problems with the sub.

    I don't know that there is a cure. The choices are not too attractive. Learn to live with it, or get rid of it and replace it.

    The really dicey part of getting rid of it is, how, in good conscience, do you sell it for a decent price, given that it hums.

    Regards
     
  18. Alex/d

    Alex/d Stunt Coordinator

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    Can you unscrew the Amp plate (you know, just like the Paradigm I bought from you) and put your ear close to it when it hums??

    If so....it could be a bad capacitor...sometimes when they go bad, they squeal a bit..

    If not a cap.. then I'd have to look.

    As far as if it isn't a part of the amp... then try a power filter and a terminator on all other plugs.
     
  19. Cees Alons

    Cees Alons Moderator
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    Little side track:

     
  20. Seth=L

    Seth=L Screenwriter

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    thanx
    Seth=L
     

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