Cheater plug is a godsend for reducing hum

Discussion in 'Audio Hardware' started by JohnnyK, Feb 12, 2003.

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  1. JohnnyK

    JohnnyK Senior Member Thread Starter

    I solved my 60 Hz hum problem by using a $1.00 cheater plug.

    As you may know, I have been fighting a hum problem caused by a ground loop. Last night I unplugged my DVD player from the wall outlet, and the hum went away. I thought that this was odd, since all my electronics are on the same circuit. I plugged in the DVD player back into the wall and then unplugged the projector---the hum stopped.

    When I had my home theater room built, I told the electrician to put all the outlets on the same 20 amp circuit to eliminate any potential ground loop problems. It seems that he put the projector on a separate circuit from the electronics. Since the projector is connected to the DVD player by component cables, there is the potential for a ground loop. I put a cheater plug on the projector and now I have no hum, just wonderful silence.

    I guess the key in preventing a hum caused by a ground loop is to make sure that everything is on one circuit.
     
  2. Jeffrey

    Jeffrey Forum Hall Of Fame

    Location:
    South Texas
    Hi John,

    Congrats! :cheers: Sounds like $ well spent. :)

    -Jeffrey
     
  3. -=Rudy=-

    -=Rudy=- ♪♫♪♫♫♪♪♫♪♪ Staff

    Location:
    US
    Very interesting!!

    I just hope there aren't any bad consequences down the road. If the power outlet's ground was connected to chassis ground, as well as the connection to your DVD player's cable, I worry that an electrical fault in the projector would send a 110v signal down this ground to the DVD player and, then, the rest of your system. I doubt it happens much with modern equipment, but there's always a slim chance. One thing to try might be to run a separate ground wire from the cheater's ground lug over to the rest of your equipment, and ground it to the outlet at that point.

    I wonder if maybe the projector's socket was wired to use the opposite phase of your house's power circuit. Just a longshot. Not sure if it would contribute to a ground loop or not.
     
  4. JohnnyK

    JohnnyK Senior Member Thread Starter

    That is a good point. I will take a look tonight. Maybe I can move the projector's breaker to the same phase as the other electronics.
     
  5. GoldenBoy

    GoldenBoy Purple People Eater

    Location:
    US
    Good for you.:goodie: :cheers: Unfortunately, I myself am still fighting a hum in my system whenever I connect my TV, VCR, or Satellite receiver to my AV Receiver and I've tried just about everything: cheater plugs, surge protector/RF filter, switching outlets you name it and the hum has been reduced, but not eliminated. So, for now, I don't attach anything having to do with the antenna or satellite dish to my AV receiver. :( Fortunately for me, my DVD player is not attached to the TV or VCR, so it doesn't cause any problems.
     
  6. JohnnyK

    JohnnyK Senior Member Thread Starter

     
  7. lukpac

    lukpac Senior Member

    Location:
    Milwaukee, WI
    Yeah...it's a much better idea to fix the electrical system (either by putting the projector on the same circuit as the rest, or checking which bus it's on) than to use a cheater plug. Systems are grounded for a reason, folks...
     
  8. Dave

    Dave Esoteric Audio Research Specialist™

    Location:
    B.C.
    Hey GB have you tried the Radio Shack cable shunt filter yet? About $10.00 I believe and it attaches to the end of your cable line.
     
  9. BradOlson

    BradOlson Country/Christian Music Maven

    Although my DVD player and digital cable are hooked up to my stereo in my bedroom, they aren't causing hum problems at all on my low budget setup. The only hum I have to minimize is the output humming from the DJ mixer by moving the output cables on the back of the mixer to amp for vinyl and Booth for CD and mixing the sound with the volume controls, I have no problems at all. I use cheap RCA cables as they are all I really need.
     
  10. GoldenBoy

    GoldenBoy Purple People Eater

    Location:
    US
    I have not tried the Radio Shack product yet, but a similar product that helped a little, but not 100%. I have not yet had the opportunity to stop into Radio Shack, but I plan to eventually. I just need to get around to it.
     
  11. Gary Freed

    Gary Freed Forum Resident

    I was amazed but grateful when I opened the box on my SACD player and found that Sony supplies a cheater plug with the player.

    I don't know if there are too many companies that do that sort of thing.:)
     
  12. -=Rudy=-

    -=Rudy=- ♪♫♪♫♫♪♪♫♪♪ Staff

    Location:
    US
    For the satellite dish, and outdoor antennas: I think that electrical code may require that the hardware (the actual dish or antenna) be grounded via a grounding rod outside to dissipate potential lightning. (Copper rod driven several feet into the ground.) As for the ground conductor in the coax, that would also be grounded to the grounding rod.

    I wonder if there is some kind of isolator for antenna and satellite input leads?
     
  13. John Moschella

    John Moschella Senior Member

    Location:
    Christiansburg, VA
    The thing you have to realize is that by removing the ground connection via the three pronged plug your projector now sees ground via the interconnecting cables to your DVD player and (assuming the DVD player has a two proged plug) from the DVD player to the component that has the three pronged plug. This is not really bad if the outer conductors on these cables combined have a heavy enough gauge to carry the currents is need be.

    Not strictly true. To really eliminate ground loops you have to have a single point ground. If the chassis grounds on your components are all connected electrically like most are, then that means only one three pronged plug for the entire system will assure a single point ground and no loops. Now with short interconnects having multiple three prong plugs will probably not result in an audible ground loop. But if you using long interconnects like in a HT, you may still get an audible loop even if your on the same circuit. Having the same circuit helps, buts its not a cure-all.
     
  14. JohnnyK

    JohnnyK Senior Member Thread Starter

    Re: Re: Cheater plug is a godsend for reducing hum

    John,

    Thanks for the good information. The interconnect between my ceiling mounted projector and my DVD player is 10 meters long.

    Regarding the single point of ground, since the projector (two prong plug) is connected to the DVD player (two prong plug) which connects to the surround processor (three prong plug)---I would assume that the processor is the single point of ground. All interconnect cables are Monster Cable, which seem to be heavy duty cables. I guess that they can handle the ground current???
     
  15. teaser5

    teaser5 Cool Rockin' Daddy

    Location:
    The DMV
    Grounding Rod

    I have one of those things...my lawnmower loves it!
    :D
    Peace
    Norm
    real name: Lawnmower Man
     
  16. John Moschella

    John Moschella Senior Member

    Location:
    Christiansburg, VA
    Re: Re: Re: Cheater plug is a godsend for reducing hum

    Johnny,
    I do exactly the same thing except I use the cheater plug at the other end (on my power amp) and leave the three pronger on my projector. My rational is that the projector is the most valuble component in my system.

    The other thing is that normal power line conditioners will not eliminate a ground loop. However an isolation transformer probably would greatly reduce any hum because it adds inductance to the ground path.
     
  17. petzi

    petzi Forum Resident

    Location:
    Germany
    Cheater plug? What is that? Is it to disconnect the device from ground, while connecting it to mains? If so, using it is dangerous.
     
  18. Dave

    Dave Esoteric Audio Research Specialist™

    Location:
    B.C.
    Petzi,

    120V is a lot safer than 220V. Sometimes we must make compromises to eliminate unwanted noises in our systems. I'm running SS. From every component to my line conditioner the grounds are used. From my line conditioner to a Realistic digital timer (from 1988 cost $15.00, cheapest tweak I ever purchased that really worked:D), at this point is where I had to slip the ground. An electrician guaranteed that I would never have a problem and never have in running it 5 years in this manner.
     
  19. DaveD

    DaveD Member


    Rudy, there are three that I know of. One is by Mondial and costs $100.00, the other one also costs the same and is sold by Music Direct. I would have to look up the brand.

    The one that I use was recommended by a Hafler techinician and costs less than $10.00.
    It looks like a regular coax surge suppressor, but isolates the ground. It is now sold by GC Electronics, part number 32-3185. The package says Coax Surge Suppressor. On the unit it is labeled Cable/VCR Ground Breaker Feed Thru. That pesky hum is from the cable ground interacting with the audio system ground, and this little guy makes it disappear.

    I got mine from my local mass market electronics store. Stock up in case they become unavailable.

    DaveD
     
  20. petzi

    petzi Forum Resident

    Location:
    Germany
    Well if you are more careless with 120 V than I am with 230 V then I doubt that you are safer :D

    You do realize we have recessed plugs and other strict safety standards for electricity?

    But you are probably right, the chance of dying from a 120V AC shock is lower than from a 230 V AC shock. I caught a 230 V shock once by the way while experimenting.

    But I still think that hum problems should be solved, and can be solved in my experience, without resorting to improper electrical installation.

    If your electrician said it's OK, it probably is. Here in Germany an electrician who makes electrical installations that violate the rules of the Society of Electrical Engineers (VDE) would risk having his business shut down, and he'd have infinite liability.

    On a side note, maybe 10 years ago the nominal voltage in Europe was raised from 220 to 230 Volts (380 to 400 volts for three-phase AC)
     
  21. aashton

    aashton Here for the waters...

    Location:
    Gortshire, England
    Depends which bit of Europe you were in - here it was reduced from 240v to 230 v ;)

    All the best - Andrew
     
  22. petzi

    petzi Forum Resident

    Location:
    Germany
    Well I consider you folks European, but it appears to me that many of you don't... Or why do so many of you island dwellers speak of "the Europeans" when you refer to those on the continent ;)
     
  23. JohnG

    JohnG PROG now in Dolby ATMOS!

    Location:
    Long Island NY
    My Home Theater runs 2 amps and 2 large subwoofers with all the related speakers for good HT sound. When I added my last sub (the impressive SVS 25-31CS+) which needed it's own amp, the new amp (an AudioSource mono) added hum to my system for the first time.

    A cheater plug on that amp solved the problem. I have no problem with this because that amp is rarely turned on and only for short times (only when watching DVD's).




    JohnG
     
  24. JohnnyK

    JohnnyK Senior Member Thread Starter

    Not all electrical devices in the U.S. have three prong plugs. My projector, processor and amp have three prong plugs, while my DVD player and my SACD player have two prong plugs. However, all two prong plugs in the U.S. are polarized so that it is impossible to accidentally plug the neutral prong on the plug into the positive slot of the wall outlet.
     
  25. KeithH

    KeithH Success With Honor...then and now

    Location:
    Beaver Stadium
    My Sony SCD-777ES SACD player came with a cheater plug, and I use it. I heard a distracting hum without it. Few manufacturers supply them, but I am very glad that Sony did.
     
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