reciever humm

Discussion in 'AV Receivers' started by Dave Shepard, Nov 29, 2003.

  1. Dave Shepard

    Dave Shepard Agent

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    I have bought Denon 3803 and ever since I have hooked it up I have been having a humming sound comming from my speakers when no sound is being played. It is a slight humm but can be heard from my chair accross the room (25ft), when I turn on the TV the humm gets slightly louder. The other night my wife and I were looking into the problem and pulled the plug on the sat. reciever and an even louder deep pop or thump sound came from the speakers and the humm got softer but still there. Anyone have this happen? what did you do to fix it? I have moved the speaker wires awa from the power cords so that isn't thew problem and have also moved the sat. to another outlet and still the same problem. Can this cause any sound quality problems? I also can't seem to get the mids or highs on the polk 70's to sound even close to what I heard at CC.

    Thanks

    Dave
     
  2. Steve*W

    Steve*W Agent

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    Is it all the speakers that hum, or just certain one's?
     
  3. Dave Shepard

    Dave Shepard Agent

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    all speakers less the sub
     
  4. Chuck Kent

    Chuck Kent Supporting Actor

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    It's not normal. It could be the receiver but you need to go thru one thing at a time to discover what the cause of the hum is, receiver or not.

    My initial guess is that is isn't the Denon. But what you need to do is start from ground zero and build your setup one piece at a time, listening for the hum as you go. Don't make or break any connections while the unit is powered. If you make a boo boo and do something wrong while it's on, you could cause damage to the speakers or receiver!

    Start with just the receiver and the speakers. Not even the sub hooked up. If that's ok, then add the sub. Continue on adding each piece one at a time. At some point, you will find the source.

    If it is the 3803, you could try the reset procedure outlined in the back of the manual. If it still is there after the reset, then you need service or an exchange.

    My gut feeling though is that you a ground loop problem. The receiver has a different ground potential than something else in your setup. More often than not, cable/sat TV connections are the prime cause for ground loops. If this is the case for you, you or an installer will need to ground the cable/sat properly before it will go away.

    Hope this helps some. At least food for thought... [​IMG]
     
  5. Dave Shepard

    Dave Shepard Agent

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    Ground loop was the reply I gotten from another forum and was told to try a cheeter plug, but nobody where I live knows what I'm refering too, is that the name of it or just what it is refered to as? When I went to CC they had a Monster Cable outlet box they were using to filter the power for there avr's would that work? I'm assuming that that humm comming from the speakers is also there when something is playing through the speakers causing the sound to be muddy and flat sounding, correct.

    Thanks

    Dave
     
  6. Paul S

    Paul S Stunt Coordinator

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    You might try to connect a wire from the ground on your receiver (or connect the wire to any part of the metal case on your receiver) and then connect the other end of the wire to the little center screw on one of your household electric plates (this little screw is a ground, it does more than just hold the electric plate on the wall) It can't hurt anything and it just might make that hum go away. It's certainly worth a try.
     
  7. Dave Shepard

    Dave Shepard Agent

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    I have spent the better part of the day fiddleing around with the set-up and I noticed two things. The sat. cable has a ground wire not hooked to anything and the set-up in the Panny DVD player has a on/off DVD video switch and it was off. With it turned off it will still play DVD-A and all DVD's but will not let the true multi-channel (DTS, DD etc) thru and the reciever would go to neo-6 or Pro Logic, I have no idea how this happened but when I changed it to on and put in a DVD-A the sound came to life. What a diff. I will connect the groung and hopefully that will take care of the other problem but I can already hear a diff.

    Thanks

    Dave
     
  8. Michael Cucka

    Michael Cucka Stunt Coordinator

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    A couple of other thoughts...

    A "cheater plug" is simply a three-to-two prong plug adapter - readily available at any hardware store for cheap. That solved a ground-loop hum I had with a Velodyne sub in the past.

    I beleive the Denon's have a "tone defeat" switch, bypassing the treble/bass controls. Engaging this is a always a good idea for the best sound quality and likewise eliminated a hum I had from an older Denon (5700).

    Finally, if you get the hum when nothing is plugged into your receiver except power and speakers (or if the unit itself hums), check your lamps/lights/dimmers whcih can introduce of noise into the electrical line. I once bought a new lamp for an upstairs bedroom which made my Marantz 9200 hum - downstairs! Trial and error all the way to figure that one out...[​IMG]

    Good luck -
     
  9. Chuck Kent

    Chuck Kent Supporting Actor

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    Just a heads up on cheater plugs...

    If the component(s) you are working with don't have 3 prongs (hot, neutral and ground), then a cheater plug won't make any difference. Also, and most important of all is that if a cheater plug solves a problem, then there is a ground loop issue. And if a cheater plug is in permanent use under these circumstances, and an electrical component should have some type of problem that causes it's outer case to become electrified, anyone touching the case could be seriously shocked/injured. The best solution is that if a cheater plug helps, diagnose and find the problem, fix it and stop using the cheater plug.

    As for the Monster filter (or whatever brand)... if (and at this point we still don't know) the problem is a ground loop issue, then if something's not properly grounded, the AC filter still leaves the main problem unsolved.

    You don't say but have you had a chance to put your system together one piece at a time? This approach won't cost you anything to do and it will reveal the source of the hum. Please don't spend any money on this until you know what's wrong...
     

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