removing ground plug

rooftop59

So my parasound HCA 1000 has a hum when plugged in normally, but it goes away if I use a cheater plug (this is the case with a lot of parasound amps from what I have read?). So does using the cheater plug basically negate the point of using a Pangea or other after market power cord? I know I should let my ears by the judge, but I am interested to hear a more scientific explanation. Maybe I should call Tony at Parasound...

Dennis Gardner

Does it negate it? Only your ears and the fact that you "know" it is there will matter. There isn't really an audiophile answer other than some of the PS Audio offerings that have removable ground pins. This feature does away with the need for the cheater and keep the audiophile nature of the better power cord intact.

The real downside to using a cheater plug with better power cord is the distance that the cheater adds at the wall outlet to an already oversized cord, making them hang loose to easily.

Moose68Bash

Is it really a good idea permanently to disable the ground?

Should be better to find and eliminate the cause of the hum.

Inspector 24

It's a ground loop. They generally develop when gear is plugged into different outlets and/or circuits and the easiest path to ground suddenly becomes your interconnected audio gear, no longer the circuitry in the house. If you can find a way to develop a stronger ground connection between the various outlets/circuits I believe the problem would go away.

I had this issue as well. I pulled the ground plug on my HCA-2003a and projector. Problem solved.

tonyb

You'll get many different opinions, but look at it like this. If your amp had no hum, and you used an upgraded power cord to a crappy .99 cent construction grade wall outlet, would that negate the Pangea ?

Of course not.

Try switching out the wall outlet to a hospital grade one or better. A non current limiting power conditioner would help too. Are you rca interconnects of decent quality ? You can also try running a small wire from a case screw on the amp to another case screw on another piece. Sometimes that works, sometimes it doesn't, cost you nothing to find out though.

Inspector 24

tonyb wrote: »

You can also try running a small wire from a case screw on the amp to another case screw on another piece. Sometimes that works, sometimes it doesn't, cost you nothing to find out though.

Can't remember if I tried this last time I was hunting a ground loop problem, butni think I'll try it again!

jeremymarcinko

That method worked for me when I had a ground loop issue. However since, I have moved my gear to the other side of the room which only only 10ft or so from the breaker box I no longer have a problem. As mentioned be sure all of the equipment is on the same circuit, preferably the same outlet. My problem was my Tv was grounding through my amp, traveling back through the HDMI and then through my receiver and so forth. Running a ground wire from the AVR to the Ground terminal on my Panamax created a shorter, more direct path to ground and the ground loop was thereby terminated. There is no safety issue with removing the ground pin from the power cable though because the amp is grounded through the TV or Avr (whatever unit it is physically connected to that has a ground pin). The only problem is if the Amp would short than it wouldn't send the energy to its own ground and could possibly send the high voltage through the other equipment on it's way to ground, which could potentially cause damage to your other connected components. However, with ground pin left in then any other shorted component would send it's voltage through your amp because it has the best ground. Bottom line it's okay to remove the pin from the amp's power cord or the other grounded component but not both, as long as one connected component is grounded then their isn't a safety issue.

rooftop59

Well this has never happened with other amps in the exact same spot plugged into the same equipment, outlet, etc., so that is why I am a bit surprised. Okay thanks guys, I'll see if I can experiment any this weekend. I have to say that I am confused about this:

There is no safety issue with removing the ground pin from the power cable though because the amp is grounded through the TV or Avr (whatever unit it is physically connected to that has a ground pin).

So are you saying that since the amp is connected to another piece of equipment that is grounded, that that grounds the amp???

jeremymarcinko

Yes, another piece of equipment that has a three prong, and a physical connection like interconnects, coax, or HDMI. For extra piece of mind you can always run a wire from the chassis of any piece of equipment to the center screw that holds the outlet cover on. That screw is always grounded as well. The idea is to eliminate the ground loop by creating a shorter or more efficient path to ground than the one provided by the amp. Grounding the AVR directly fixed my previous issues, and I never had to remove my ground pin from my amps power cable.

rooftop59

Thanks Jeremy, very helpful!

Speedskater

jeremymarcinko wrote: »

Yes, another piece of equipment that has a three prong, and a physical connection like interconnects, coax, or HDMI.
Bottom line it's okay to remove the pin from the amp's power cord or the other grounded component but not both, as long as one connected component is grounded then their isn't a safety issue.

This is totally and absolutely FALSE!
The Safety Ground wire's purpose is to trip a building circuit breaker under fault (short circuit) conditions. Typical US fault currents range from 150 to 1000 Amps until the breaker trips. That's way the Safety Ground wire needs to be as large as the Hot wire. Under no conditions can you safely remove the Safety Ground.

tonyb

Speedskater wrote: »

[Under no conditions can you safely remove the Safety Ground.

I suppose that's why they make power cords with removable ground pins....because they want the liability of you burning your house down.

thsmith

PS Audio PCs have removable ground pins.

F1nut

thsmith wrote: »

PS Audio PCs have removable ground pins.

Yes they do and if it is slightly loose it will cause noise, which will drive you nuts for months trying to figure out what the h e l l is wrong. I put Loctite thread locker on mine after that *%&$#!***** episode.


Pangea has them now as well.

F1nut

Speedskater wrote: »

The Safety Ground wire's purpose is to trip a building circuit breaker under fault (short circuit) conditions. Typical US fault currents range from 150 to 1000 Amps until the breaker trips. That's way the Safety Ground wire needs to be as large as the Hot wire. Under no conditions can you safely remove the Safety Ground.

Are we talking any grounded outlet or just those awful ground fault ones that fail all the time?

jeremymarcinko

Speedskater wrote: »

This is totally and absolutely FALSE!
The Safety Ground wire's purpose is to trip a building circuit breaker under fault (short circuit) conditions. Typical US fault currents range from 150 to 1000 Amps until the breaker trips. That's way the Safety Ground wire needs to be as large as the Hot wire. Under no conditions can you safely remove the Safety Ground.

Sure there is some safety risk in removing the ground pin. In the unlikely event something would short in the amp, the chassis could become live, but it would still trip the breaker through the interconnected equipment that has a physical ground. The audio cables are still substantial enough to handle the the current for split second it takes for the 15 to 20 amp circuit breaker to trip. In addition I have never seen an amp without a built-in fuse. The fuse will also burn and break the circuit if a short would occur. But your right, if the amp would short and the fuse failed to do its job and the interconnected cables burned up before the breaker trips and one failed to see the carnage or smell the smoke and continued on to touch the amps chassis then sure they might get a shock. Then again likely not harmful, the circuit breaker should then trip, but if it is faulty, then one may be in a bit of trouble. But 110v is generally safe unless you can't get away from it, for instance if you were standing in water and the shorted amp was too then you might be sol, which us why we have the added gfci protection in our sinks and bathrooms. So yeah your right given the right scenario removing the ground pin could be unsafe...technically. Thanks for pointing this out, I could have killed someone.

MetropolisLake

I view it like this... every single audio component manufacturer out there will say to NEVER bypass the ground with a cheater plug for this purpose, and given that they probably know quite a bit more than I do, its probably best to listen.

Dennis Gardner

MetropolisLake wrote: »

I view it like this... every single audio component manufacturer out there will say to NEVER bypass the ground with a cheater plug for this purpose, and given that they probably know quite a bit more than I do, its probably best to listen.

What about the huge numbers of CD players, DVD players etc. that bypass a ground? Isn't that what a 2 prong plug is?

tonyb

MetropolisLake wrote: »

I view it like this... every single audio component manufacturer out there will say to NEVER bypass the ground with a cheater plug for this purpose, and given that they probably know quite a bit more than I do, its probably best to listen.

....and every manufacturer touts their audio gear as the next best thing to sliced bread, you listen to that too ?

jeremymarcinko

CPSC and liability...have to protect those who don't know better.

MetropolisLake

Dennis Gardner wrote: »

What about the huge numbers of CD players, DVD players etc. that bypass a ground? Isn't that what a 2 prong plug is?

If it's a floating case then you can rock a two prong plug all day long, doesn't matter. If it has a three prong plug and you purposely bypass it, that's a different story.

ZLTFUL

Yay! Another "expert".

MetropolisLake

What exactly do you guys think the ground wire is for anyway? It would be a heck of a lot easier and cheaper to just supply two prong plugs on everything if they do nothing but induce ground loops.

tonyb

Who said they just induce ground loops ?

If it was so dangerous, cheater plugs and power cords with removable ground pins would be illegal not to mention the liability issue manufacturers would face.

MetropolisLake

tonyb wrote: »

If it was so dangerous, cheater plugs and power cords with removable ground pins would be illegal not to mention the liability issue manufacturers would face.

Peavy did a great writeup on this, I tried to post the link but it has to be approved I guess. They gravely warn against doing it, I'm assuming because they are concerned about liability. Other manufacturers as well as professors and industry groups warn against it as well. I'm just not sure why everybody takes it so lightly. They don't write this stuff to sell more products or confuse everybody. "Don't do this, you very well could die" isn't exactly the greatest sales pitch in the world.

jeremymarcinko

Geese people roll the dice everyday, don't they? Tobacco companies gravely warn about the dangers of smoking, Motorcycle companies gravely warn about the risks of not wearing proper safety gear, the weather man gravely warns us about every possible weather condition, lots of gravely warning on the side of a bottle of advil and a warning on the side of a cup of coffee, kids nowadays have to be in a booster seat until there 300lbs and 30 years old or something. I read today it isn't safe to go for an extended run without a heart monitor in case you didn't know your heart was going to explode. Come on how many years were homes built with only two prong outlets? We calculate the risk and make choices. Sure the ground pin makes it safer... we can always be safer, but removing a ground pin or using a cheater plug isn't on my list of real concerns and certainly doesn't mean an imminent death.

MetropolisLake

Yeah I dunno, maybe the risk is overstated. I grew up in fear of electricity, my dad was an electrician, he's been shocked by 480 volts before, which is no joke. For some stupid reason I turned around and went to electrical engineering school after all that. Mistake. A/C freaks me out. I don't like taking risks with it.

MetropolisLake

tonyb wrote: »

MetropolisLake wrote: »

I view it like this... every single audio component manufacturer out there will say to NEVER bypass the ground with a cheater plug for this purpose, and given that they probably know quite a bit more than I do, its probably best to listen.

....and every manufacturer touts their audio gear as the next best thing to sliced bread, you listen to that too ?

When it comes to general safety warnings where they have no reason to say what they're saying, yeah I tend to listen. It's not just manufacturers who say this either.



http://www.record-producer.com/ground-lift-what-is-it-what-do-you-do-with-it-what-do-you-do-if-you-haven-t-got-it#.VMrHxmjF9W1

"Where equipment requires an earth, it is vital to life not to disconnect it."



http://peavey.com/support/technotes/safety/shockhazard.cfm


http://www.epanorama.net/documents/groundloop/why_grounding.html

[Deleted User]

Hello,
The reason to have a safety ground on a power amplifier is that if the chassis doesn't have it's own path to earth ground and the AC hot becomes shorted to the chassis anyone touching it could be shocked. This would be important for professional gear that is often moved around and can receive rough handling, perhaps increasing the likelihood of internal wires becoming loose. No manufacturer is going to tell you to remove a safety feature placing themselves liable if a problem occurs. Kind of like Toyota telling you not to use your seat belts.
If your system has humming caused by a ground loop it is best to solve the grounding problem and leave any safety ground intact. Humming is caused by either too many grounds at different voltage potentials or not enough proper grounding. Using a cheater plug should only a temporary solution.
Ken

tonyb

I've used cheater plugs off and on for 20+ years with the longest time frame of 5 years continuously. Never a hiccup, shock, weird stuff happening.

Under certain conditions, like Ken suggests, it is possible for the chassis to become energized, but you have interconnecting cables to carry that to another grounded piece. Most newer gear will shut down anyway if a proper electrical circuit isn't happening. Vintage gear and higher voltage tube amps are another story. Even some SS amps have ground lifting switches built in.

A lot depends on design and voltage of a piece. Most receivers, smaller components, would be fine on a cheater plug, but higher voltage vintage stuff and tube amps would not.

Cheater plugs or removable ground pins are not a one size fits all solution and shouldn't be viewed as such.

MetropolisLake

tonyb wrote: »

Under certain conditions, like Ken suggests, it is possible for the chassis to become energized, but you have interconnecting cables to carry that to another grounded piece.

The ground wire in XLR cables seems to be able to do this. When all your equipment has an earth ground, you can do a ground lift which ditches this wire, and any ground loop goes away. Or, if you have a bunch of equipment in a rack, you can ground one piece of equipment but not the others, and if they're connected with XLR cables, I think everything is still grounded and probably still no ground loop.

What I don't understand is how RCA cables work in this situation. I'm not sure they still ground everything but some people say they are. I guess if you're getting ground loops with them plugged in maybe they are. Seems to me that they would be the equivalent of both blanking out the hardwired ground as well as doing a ground lift via XLR cables, which is not grounded. I don't see how you can be truly grounded in that situation with RCA cables but I'm not sure of the difference in internal wiring of components that use XLR cables vs. RCA.