I have a "HUM" of a problem

Discussion in 'AV Receivers' started by Kevin. W, Jun 23, 2003.

  1. Kevin. W

    Kevin. W Screenwriter

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    Well I just hooked up my new Rotel RMB-1095, replacing my Rotel RMB-1066. Now I have a "HUM" coming from my speakers. The only difference to my system is that the 1095 has a 3prong power cord and the 1066 was 2prong. I'm going to start trouble shooting the setup this evening, by disconnecting everything then adding it back one connection at a time. Anyone have any ideas why going from a 2 to 3 prong connection to an amp would cause the problem to show up. Before my setup was as quite as a mouse.

    Kevin
     
  2. Chu Gai

    Chu Gai Lead Actor

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    ground loop maybe due to the cable...try disconnecting it from your system and see if it goes away.
     
  3. JamesHl

    JamesHl Supporting Actor

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    Well, you can't tell if the hum is gone when the amp is unplugged Chu. I mean of course it would be gone, as there would be no power. However, you need to have it plugged in to use it... I digress.

    What I have seen others say to do is use a 'cheater' plug which will make the 3 prong 2, thus eliminating the extra ground.
     
  4. Kevin. W

    Kevin. W Screenwriter

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    I've figured out the problem is due in part to the cables(AR Master series) hooking my Marantz pre/pro output to the amps inputs. If I disconnect them one at a time the noise gets louder, and at one point I began to get radio signals coming through. Once all the cables are disconnected the hum/buzz is to a point where your ear has to be right against the speaker to hear. Unfortunately I can't get a hold of a cheater plug to test with everything plugged in. Would using my 2 prong powercord from my other amp be the same as using a cheater plug?

    Kevin
     
  5. Chu Gai

    Chu Gai Lead Actor

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    i should've been more clear. if your cable for the TV is connected to your system, disconnect it and see if the hum persists.
     
  6. ChadLB

    ChadLB Screenwriter

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    Kevin,
    I seem to be having almost the same problem as you with my Parasound amp. I unhooked all wires except the speaker wire going into my 5th channel on my amp. The hum noise is still there unless I unplug the +/- wire then it goes away. Anyone have any ideas for me. I am using a cheater plug also. I have no cables going into my reciever and my receiver is actually off at this point. The only thing that is turned on is the AMP and I still get a hum/hiss noise.
     
  7. Levesque

    Levesque Supporting Actor

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    I have a RMB-1095, and it's humming like crazy. The only way to solve the problem is to use a cheater plug for me. I've tried everything, and I mean everything, and only the cheater plug is working.

    2 weeks ago, I just add a Bryston 4BSST to my system, and guess what... pure silence for the front. So I think the RMB-1095 is having a problem in the grounding department. Even the Rotel tech told me the grounding scheme was probably different in the Bryston, explaining the absence of a hum.
     
  8. Kevin. W

    Kevin. W Screenwriter

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    Levesque, how long have you been running the cheater plug? Ever have a shock off your amp when you touched it? DOn't want to fry my son when he's using the setup.

    Kevin
     
  9. JohnRice

    JohnRice Lead Actor

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    Levesque, I think Bryston amps usually have a switch to lift the ground connection if necessary. Basically the same as using a cheater, but probably safer. You may have the ground lifted.
     
  10. Levesque

    Levesque Supporting Actor

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    I use a 12V trigger to switch the Rotel on and off, so I've never touched the Rotel since it's in the rack. So how can I get a shock if I never touch it?

    I know it's really dangerous...but after paying 2 electricians and losing a lot of my precious time, I can't live with a hum that I can hear from 10 feet... so I use the cheater plug...
     
  11. DavidES

    DavidES Stunt Coordinator

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    M.D.
     
  12. Kevin. W

    Kevin. W Screenwriter

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    I was able to get a hold of a cheater plug and it did nothing for the hum/buzz coming form the speaker. It looks like I'll need to run a seperate line for the amp, since the noise goes away completely when I remove everything plugged into the powerbar(AR-10s), except the amp.

    Kevin
     
  13. Chu Gai

    Chu Gai Lead Actor

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    well before you do that, temporarily try running an extension cord to another outlet on a different line. might give you a handle on if a separate line's gonna do the trick.
     
  14. ChadLB

    ChadLB Screenwriter

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    Chu,
    I tried that for my problem and that didn't change a thing. The cheater plug got rid of the hum coming from the TV but I still have a buzz coming from the speakers. The only thing is I move in a month so I will wait until then to look into it more....
     

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