Follow-up to HUM AND BUZZ- where to go now?

Discussion in 'Archived Threads 2001-2004' started by Mike_Ch, Dec 9, 2001.

  1. Mike_Ch

    Mike_Ch Stunt Coordinator

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    After adding a power amp to my HT, I experienced a buzzing noise which was addressed by a number of people of whom I am grateful to in a previous post:
    Thread- Added a power amp now HUM and BUZZ- HELP!
    Well, the cheater plug got rid of the buzz, but due to safety concerns regarding the loss of the ground, I took it out. I have tried connecting a ground wire (using speaker cable at the moment- is this OK???) between the amp chassis and the ground wire screw on the Denon receiver (which has a 3-prong plug same as the Rotel amp btw), and this has significantly reduced the buzz to a point where it is just audible from the listening position (although the cheater plug made the buzz inaudible). Can anyone explain what has just happened? Are there any other things I could try to eliminate the buzz completely without using the cheater plug? Although the buzz is reduced, it is still annoying. Thanks for the help,
    Mike
    Edit: I should add that connecting the ground wire from amp to the DVD player reduces the buzz the same amount as adding the ground wire from amp to receiver. Again, if I unplug the DVD player then I get no buzz. Strange this!
     
  2. Mike_Ch

    Mike_Ch Stunt Coordinator

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    ne1? [​IMG]
     
  3. Ron Reda

    Ron Reda Cinematographer

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    Mike,

    I did the same thing (added an amp) and am getting the same results (HUM/BUZZ). I am pretty much at a loss for what to do. I think the ground is my house is messed so I'm planning on giving my electrician a call to check it out.
     
  4. Bob Christensen

    Bob Christensen Stunt Coordinator

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    Ground loops are a pain to ferret out. If you have a ground loop, you will likley have a 60 hz hum (compare to a 60 hz test tone). All components need to be grounded to a common ground. Even different outlets in the same room can have different ground potentials and can cause current to flow through the grounds (or chassis). First make sure that your HT outlet is, indeed grounded properly. Next, try running all your HT mains to this plug (even temporarily). Does the hum-buzz go away? If so, concentrate on your house electrical system (call an electrician). You need all your HT outlets to share a ground (not just a common ground). If the hum-buzz does not go away, you likely have a bad component (as simple as a bad wire, or as complex as a bad transistor in a major component). Unplug one component at a time (power off please!) until you isolate the defective component.
     
  5. BruceD

    BruceD Screenwriter

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    Do you have the option of connecting your DVD player to the receiver with a toslink cable?

    Try this and see if the hum disappears.

    If you need to you can get a coax toslink adapter from partexpress, for about $25 IIRC.

    BruceD
     
  6. Ron Reda

    Ron Reda Cinematographer

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    It sounds as though I'm getting interference from my TV. Last night, I turned all of my components on systematically in hopes of finding out the source of the dreaded hum. The amp was already on, so I turned on the Denon 3802 next. Once the Denon was turned on, there was only a slight, faint hum and that was only when I put my ear right up to my speakers' tweeter (I've actually heard that it's normal for tweeters to give off a slight hum). Anyway, I turned on the DSS receiver next...no hum. Last, I kicked on the TV...BINGO, the hum came out in full force. In fact, it was the same "volume" that it was when I originally discovered the problem Sunday (again, I heard it from my sitting position 14 feet away).
    So, here's what I did. First, thanks to John Morris (a felow HTF'er), I called up Electrotex, a audio/video store out in Texas (www.electrotex.com) and ordered a ground loop isolator for $6. I'm not sure if this will be the fix, but I figured I might as well go ahead and get one while I'm still researching my problem. Also, it was only $6, so no great loss if it doesn't work. Next, I gave an electrician a call. If my problem is what I think it is (a grounding issue in the house), it's going to require professional attention to remedy the situation. Originally, I tried a cheater plug on my amp and while it did rid the system of the hum for a little while, it came back in a few hours. Also, after reading about all of the dangers of taking the ground out of an amp's power cord, I'm not really comfortable with the idea of leaving it on there any longer.
    Keep in mind, I'm a complete moron when it comes to electricity, so here's the big question, what do I ask the electrician to do? I think that first, he's going to have to check the grounding in the house. Should I also ask him to run a different circuit just for my HT equipment? Any other questions???
     
  7. Jagan Seshadri

    Jagan Seshadri Supporting Actor

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