Amp Hum?

Discussion in 'Archived Threads 2001-2004' started by Sean_B, Aug 21, 2002.

  1. Sean_B

    Sean_B Stunt Coordinator

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    I have a humming noise when my amp is turned on. Its a parasound 855 5ch. amp. What do I need to do to rid of this? Or is this something I have to live with?
     
  2. Greg Haynes

    Greg Haynes Supporting Actor

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    The quickest way to fix it is to buy a cheater plug from RadioShack. You can do a search on "cheater plug". You will come up with alot of results.

    However, the cheater plug should only be used to as temporary solution until you can properly ground the amp.
     
  3. Yogi

    Yogi Screenwriter

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    If the hum is coming from the speakers then it could be your cable inlet thats not ground WRT your home ground. If its coming from the amp itself then it could be the torroid. In the first case you will have to check with your cable company. they should be able to help you ground it better. In the later case you will have to open the amp and tighten the screw holding the torroid transformer. Torroids are notorious for vibration.

    See if this helps.
     
  4. David Berry

    David Berry Stunt Coordinator

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    Sean,

    I agree with Yogi's post. Most probably, if the hum is indeed coming from the speakers when the amp is on, it is a ground loop problem. I recently had that problem as well when I hooked up my Bryston 3B-ST amplifier. If you have your cable for TV anywhere in your system, disconnect it at the source and see if the hum is still present. If it is not, then it is a ground loop problem. There are numerous threads on this subject within this forum, just perform a "ground loop" search.

    As an aside, "cheater plugs" do get rid of the ground loop hum problem, but at the expense that your amplifier is no longer grounded.

    David
     
  5. Michael Mathius

    Michael Mathius Supporting Actor

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    I have a hum/buss which I've spent the last two weeks trying to solve unsuccessfully. I have even gone as far as unplugging each component and even switching from the electrical out which did help a little.

    I have a Denon 3802 and a Parasound HCA 1205 I can hear the hum once I raise the volume from -- to -64 and it never gets louder even if I'm at 00 on the receiver. My sub is connected to my receiver and I can clearly hear the hum from it. The hum is not too loud but thanks to this forum I've become very critical about my equipment so I notice it.

    Sometimes the hum is not noticeable while watching a movie on dtv but while changing channels or a source on the receiver, I can hear it.

    The strangest thing is that I have a fan in the room which sounds the same as the hum I'm getting when I runs. BTW the fan is usually off and on a different outlet.

    I don't have cable but do have dtv and ota hdtv which is grounded outside. I have tried disconnecting all cable but that did not help.

    I'm writing this at work so I may have missed something but tonight I will update this post if I notice anything else.

    Thanks.
     
  6. Yogi

    Yogi Screenwriter

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  7. Sean_B

    Sean_B Stunt Coordinator

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    Thanks for the input on this matter guys. I unattatched the cable feed going into the VCR and that was the source of the problem. However, it doesn't eliminate it totally, I can still here it faintly if my ear is up against the speaker along with speaker hiss. Why would there be any hiss with nothing playing?

    Anyways, I guess I will call the cable company on the matter. I have my doubts about them curing the problem. Would I have this problem if I were to get direct TV instead?
     
  8. Yogi

    Yogi Screenwriter

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    There is bound to be some hiss present with an external amp connected and your ear stuck to the tweeter. Dont worry about that. Its a good question about Direct TV. I wouldn't think that there should be a ground loop issue with SatTV as it would have the same ground as the house ground. Others, please correct me if I am wrong.
     
  9. Philip_T

    Philip_T Supporting Actor

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    Sean,
    I was in the same boat as you not too long ago. I called the cable company and the guy who came out wouldn't listen to me at all. He kept saying it was a problem with my audio equipment, even after I physically showed him how the amp sounded with the cable plugged into the wall (hummed) and unplugged (no hum, just music), he still refused to believe me and I was left with a $17 service charge [​IMG] . I hope you have a better experience with your cable guy than I did. I ended up buying a ground loop interupter from hometech.com (you can get them at other places as well) for $7.00 that fixed the problem, but thats $24.00 dollars that the cable company me. Not alot of money, but its the principle. Needless to say, I have sat. TV now and no filters are required for hum-free sound. Im not trying to endorse or disparage one or the other, just be careful what you sign when the cable guy comes out if he cant solve your problem. Good Luck!
    Regards,
    Phil
     
  10. Amir

    Amir Agent

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  11. Sean_B

    Sean_B Stunt Coordinator

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    Phillip, Thanks for the insight in regards to the cable company. This ground loop interupter, could you tell me more about it? Is it like a cheater plug (which I don't want to do because I'm under the impression it is not good for the amp)?

    I may just go way of DirectTV. To heck with Cable.
     
  12. Lee-c

    Lee-c Second Unit

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