Which ground loop isolator?

Discussion in 'Archived Threads 2001-2004' started by Pamela, Mar 9, 2003.

  1. Pamela

    Pamela Supporting Actor

    Joined:
    Mar 14, 2001
    Messages:
    779
    Likes Received:
    0
    Trophy Points:
    0
    After much work hooking up my new Parasound Halo A 23 amp, I discovered a horrible hum coming from the speakers. I pulled the Radio Shack ground loop isolator from my computer set-up and placed it between the amp and receiver. Voila! No more hum. It seems to be working fine, but I was wondering if there was a better one? The Radio Shack one seems so cheap. I'm not in the "must have expensive cables" camp, but the quality seems so cheezy. Any better ones out there? Or does it not make a difference? Any that I don't have to RCA barrel adapters on?

    Much thanks for any help!
     
  2. Roger Kaufmann

    Roger Kaufmann Stunt Coordinator

    Joined:
    Dec 27, 2000
    Messages:
    119
    Likes Received:
    0
    Trophy Points:
    0
    Pamela,

    I can't vouch personally only from recommendations but Jensen makes some that are supposed to be very good. Not cheap but good from what I understand. I had a hum and came close to ordering one but my hum is 95% fixed, so I may still order.

    They're web site is: http://www.jensen-transformers.com/

    However if your RS fix is working why spend the extra money?
     
  3. Parker Clack

    Parker Clack Schizophrenic Man
    Moderator

    Joined:
    Jun 30, 1997
    Messages:
    12,220
    Likes Received:
    75
    Trophy Points:
    9,110
    Location:
    Kansas City, MO
    Real Name:
    Parker
    Another one is the MagicBox by Mondial. At $100 it isn't cheap but it is supposed to be one of the best ones out there.

    This can be reached here.

    Parker
     
  4. Chu Gai

    Chu Gai Lead Actor

    Joined:
    Jun 29, 2001
    Messages:
    7,270
    Likes Received:
    1
    Trophy Points:
    0
    have a part # for that RS product?
     
  5. Pamela

    Pamela Supporting Actor

    Joined:
    Mar 14, 2001
    Messages:
    779
    Likes Received:
    0
    Trophy Points:
    0
    Wow, the MagicBox is a bit pricey. The Jenson is not as bad. Have to check my financial situation this week.


     
  6. Chu Gai

    Chu Gai Lead Actor

    Joined:
    Jun 29, 2001
    Messages:
    7,270
    Likes Received:
    1
    Trophy Points:
    0
    well if you enjoy spending more for water by all means however there is an alternate spelling for Evian [​IMG]. However don't you think that purchasing say the Jensen would then be kind of like knowing that Donna Karan ensemble was bought at Marshalls or Syms?
    ok, enough joking around. spec's on the RS are as follows:
    Frequency Response:.............................300 Hz to 4000 Hz +/- 3 dB
    Jensen's got a toll free #, give em a call and see what their spec's are.
     
  7. JohnnyG

    JohnnyG Screenwriter

    Joined:
    Dec 18, 2000
    Messages:
    1,522
    Likes Received:
    0
    Trophy Points:
    0
    Are you not better off tackling gound loops at the source? Step one is to unplug all equipment/devices on that electrical circuit one-by-one until the hum disappears. If it goes away when you unplug your DVD player (for example), then it's likely that the player is wired incorrectly on the inside (+/- swapped). If it does not, then there might be something funky with your house wiring that you might to have checked.
     
  8. Pamela

    Pamela Supporting Actor

    Joined:
    Mar 14, 2001
    Messages:
    779
    Likes Received:
    0
    Trophy Points:
    0
    FYI

    Thanks everyone! I isolated the problem to the cable. I unhooked the ground loop isolator and ran my cable through my Power Center and that nasty hum is history. An easy, inexpensive fix. Always the best kind!
     
  9. Philip Hamm

    Philip Hamm Lead Actor

    Joined:
    Jan 23, 1999
    Messages:
    6,873
    Likes Received:
    2
    Trophy Points:
    0
    For the sake of someone searching in the future....

    I'm using a product called "Hum Eliminator" from a company called "Ebtech" in my system. My ground loop hum was caused by the compressor in my new refrigerator, and would have required major rewiring in the breaker panel to repair. The "Hum Eliminator" is a studio quality device sold in professional music stores. I bought mine in "Guitar Center". It's sonically transparrent, very high quality, and not too pricey. I highly recommend these devices for anyone having a similar problem.
     
  10. Rajeev_s

    Rajeev_s Stunt Coordinator

    Joined:
    Dec 20, 2002
    Messages:
    184
    Likes Received:
    0
    Trophy Points:
    0
    If I have a hum in my reciever, do you think I need to ground it. My old reciever had that problem. But I think its the house. Any Suggestions ? Do you think a simple ground to the third pin in the outlet would work or ground it to the house ground ?
     
  11. Lee Daza

    Lee Daza Agent

    Joined:
    Aug 10, 2002
    Messages:
    30
    Likes Received:
    0
    Trophy Points:
    0
    Rajeev,

    The way I understand it, the your hum is likely CAUSED by the fact that your receiver, or something connected to it, is grounded. That's fine, but something is generating noise in the ground circuit, and that noise is coming up the ground wire, into your receiver chassis, and out through the grounded shielding of your interconnects. This noise is added to the 'good' signal since the overall signal is the difference between the signal and the ground(anyone correct me if I'm wrong here). A major source of noise can be the shielding of your CATV cable, which is likely tied into your house ground or even a chassis within your system.

    At least that's what I can gather from Jansen's application notes, specifically AN004 and the Trouble-shooting Guide. The notes are in PDF format.

    They make the $60 VRD-1FF isolator on this page that seems to work for people.

    If the specs quoted above for the RadioShack part are correct(300-4k Hz, +/-3dB), then the Jansen version(CI-2RR) which has a range of (.25-50k Hz, -3dB), and is within -1dB from 1Hz to over 20kHz is vastly superior. Of course, it's also over ten times the price of the RS model.[​IMG]

    If you have the time to read the trouble-shooting guide, and maybe even construct the simple 'test adapters' they show, I bet you could eliminate the ground loop hum at the least costly site.
     

Share This Page