Hissing/buzzing sound thru amplifier

Discussion in 'Archived Threads 2001-2004' started by Miles Abbey, Mar 23, 2002.

  1. Miles Abbey

    Miles Abbey Agent

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    I recently purchased the Rotel 993. I notice a slight hiss/buzz thru the amplifier when no source sound is coming through speakers. Is this normal? If so, how can it be remedied.

    Thanks,

    Miles Abbey
     
  2. Dan Driscoll

    Dan Driscoll Supporting Actor

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    It isn't unusual for there to be a slight hiss, especially from the high frequency driver. But you should not be able to hear it more than a foot or 2 from the speaker. If you can hear it from farther than that, you need to check a few things.
    Disconnect the pre-amp, so that only the power amp and speakers are connected. If the hiss drops down to where you have to put your ear next to the speaker to hear it then the source isn't the amp. (This assumes you have passive, not active speakers) If it is still audible from more than a foot or 2 then make sure the amp is properly grounded. If it is, then there may be a problem with the amp.
    But if the hiss does go away then you need to start reconnecting the rest of your system, one piece at a time, starting with the pre-amp. You may have a ground loop, especially if the hiss comes back after connecting the TV or component cables to the TV. If that is the case, you may need to reconfigure your A/C power connections so that all your equipment is on the same circuit and same ground connection.
    Hooking up all your equipment (including TV/TiVO, CATV/Sat cable and phone line) to a good power conditioner will ensure that all the equipment has a common ground.
     
  3. Miles Abbey

    Miles Abbey Agent

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    The hissing goes away when I unplug my powered subwoofer. What do I do next?

    Thanks,

    Miles
     
  4. Dan Driscoll

    Dan Driscoll Supporting Actor

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    Plug the subwoofer into the same A/C outlet that the amp is plugged into. You shouldn't hear any hiss.
     

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