Finally detected where hum was coming from but don't know how to get rid of it. Help

Discussion in 'Archived Threads 2001-2004' started by Andres Munoz, Jan 3, 2003.

  1. Andres Munoz

    Andres Munoz Cinematographer

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    I'm not sure if I'm posting in the right place. If not, I apologize.

    I've been having this terrible, loud hum coming from both my subs. After connecting and disconnecting different components, I was able to determine that the culprit is my PC. I'm connecting the output of the sound card to my Outlaw 1050 receiver in order to listen to MP3s on my system. The cable used has a headphone jack on one end and two RCA jacks on the other end. When I removed the cable from the sound card output the humming stopped.

    Anyone know why this is happening and how to fix it?

    Thank you in advance.
     
  2. Aaron Rosenfeld

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    Make sure you have the cable plugged into the line-out jack on your sound card. The headphone jacks are powered and notorious for being really noisy. If you have a Soundblaster live or Gametheater XP you may want to look into using digital outs, that would eliminate any humming. Good luck.
     
  3. Brian Treinen

    Brian Treinen Stunt Coordinator

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    One other thing to check is, do you have a cable modem? My cable co. said that those things are also notoriously noisy and can cause a ground loop hum becasue they are sheiled and grounded so poorly. If you turn off the cable modem and disconnect it and the hum goes away that's your issue. To fix you might try doing the 300ohm-75ohm-300ohm adapter back to back trick. It works for my on my RPTV cable input but it also introduces a ghost in the picture since it picks up over the air signals as well. I'd rather have no hum though! Good luck.

    Oh, if it is your RCAs I know there are a couple of products you can buy to defeat ground loop hums via RCA cables. Search around here for ground loop hum and I'm sure you'll come up with something.
     
  4. Andres Munoz

    Andres Munoz Cinematographer

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    Aaron...that's a valid point. I'll make sure I'm not plugging the cable into the headphone jack.

    Brian, I did not know that about the cable modem. Another thing to check as well.

    Thanks guys.
     

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