Take the inputs out of the amp and turn the amp on. If you have no hum, the hum is coming from elsewhere. If you have many grounded units, you will typically get a ground loop or hum. This is caused by two or more routes to ground with differing potential. Unground the preamp and reconnect it to the amp with no cheater plug on its power cord. If you have no hum, go with it. Otherwise, unground other source units. Although many go with only the preamp grounded, you probably would feel more comfortable with only the amp grounded. |
Yes, You are safe. Remember, you are also grounded through the interconnects!
Regards, |
You can attach the the cheater plug ground wire to another wire and run it to a wall receptacle. Or you cand ground it to some other metal object like a cold water pipe. AS ALWAYS RESPECT THE ECLECTRICITY! |
Quincy's opinion is very bad advice. Interconnects are not an effective safety ground. |
If you ground the amp as Gregadd suggests to the wall receptacle, you will have the same ground loop. Ground only the amp to a real ground will not cause the ground loop. |
I could be off base here but I wouldn't use the Monster for my amps in the first place. I would try doing the amp into the wall and see--or is that listen? |
I dont know if its safe. But why would a company like PS Audio sell Power Cords with removable ground pins ? |
Nothing would be harmed. My guess is that it would sound better. |
TBG. I read both of your posts.I could not understand neither. A three prong converter which acccepts a three prong plug steps it down to a two prong plug and ground wire. That wire is designed to be attached to the screw of recptacle that holds the faceplate to the wall. I assume that when he used the cheater plug he was left with no place to attach the wire. It is not requireed that third wire be attched to the screw of that faceplate. It can be grounded to any structual metal. I ground my turntable to my preamp. Respect Electricity!
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The third pin is a safety ground and the cause of many woes. Many of us grew up without it and are still here. The third pin is a good idea but not absolutely necessary. Be sure to make sure your outlets have the polarity correct, this is also important. A polarity checker can be bought for five bucks. What gets me is a toaster which carries quite a bit of current and is commonly metal on the outside usually only has two prongs. Then in most new homes ground fault outlets are required in kitchens. Who's making this stuff up anyway. |
If he has two paths to ground with different resistance to ground, he has a ground loop. The cheater opens one of these paths, closing it again by attaching the wire of the cheater to the ground at the outlet reconnects it. I must admit that I am merely restating what I said as I have no idea what you don't understand in my posts. |
He starts out with amp grounded to Monster device. Device gounde to wall. Cheater plug breaks grund to device. Amp is now not gounded. Attach amp to its own ground independent of device. In my mind amp has only one path to ground. What's wrong? |
What gets me is a toaster which carries quite a bit of current and is commonly metal on the outside usually only has two prongs. Then in most new homes ground fault outlets are required in kitchens. Who's making this stuff up anyway. Yeah, who IS making this stuff up? I see a lot of "made up" electrical wisdom on this website. It really scares me to see that people with a total lack of knowledge about electrical safety requirements feel comfortable dispensing advice on electrical safety. By the way, electric toasters are covered by Underwriters Laboratories. UL 1026, "Standard for Electric Household Cooking and Food Serving Appliances," contain the relevant standards and testing methodologies. It's quite comprehensive, and testing is stringent. Last but not least - a cavalier attitude about electricity is the best way to have an electrical fire. According to the Consumer Product Safety Commission, there are over 40,000 household electrical fires every year, averaging 350 deaths per year, and over 1400 injuries per year. Average annual loss is $688 MILLION. You could be next. |
Rex, you statistic cause alarm, but we would need to know how many of these fires come from electric space heaters. This is all a red herring considering the original question about hum. |
According to a study done by Iowa State University, 2/3rds of household electrical fires begin in the plugs or cords of household appliances and electrical devices.
The point of all this ties back to the original question about hum. The point is: defeating a safety ground is STUPID. STUPID. It's even more stupid if you or a family member is injured or killed, or your house burns, because you took the lazy, ignorant path of solving ground loop problems by using an illegal "cheater" plug or other illegal methods of defeating a safety ground.
Ultimately, if someone chooses to put his family/neighbors at risk out of laziness, there's nothing anyone can do to stop him. However, I think it's the height of irresponsibility to come here and advocate illegal, potentially dangerous practices and call them safe.
Speaking of red herrings: A fire caused by an electric space heater igniting combustible material is NOT considered an electrical fire. |
Ok, I know less than most here. In most cases gfi's are in the kit. bath. Therein the closeness and potential dangers of water/ contact with said faucet / and said appliance/and you as "middle-man". I'm not going to try it but I'm sure your 2 prong toaster/and you---will trip the circuit breaker within the gfi. |
Household appliance including mainly portible heating devices?
Again you exaggerate, even if in caps. Many audio and video devices with three pin wall plugs have no connection in the device of the grounding wire. All cd players that I have checked, both of the preamps I have, and the phono stages lack any chassis ground. The primary reason is gound loop problems.
How precisely would you cope with ground loops, oh superior one?
It is circuit breakers that are the primary electrical protection. It would be really stupid to put a penny into the fuse box as people used to do before breakers. |
For a discussion of groundloops and how to solve them go to:
http://www.epanorama.net/documents/groundloop/index.html
If I enterd that wrong just type groundloop into your internet browser. |
This gives a good explanation of what the problem is and why it exists, but it is mainly for AV systems. It does suggest starting with the amp only in the system. You will probably not have much hum. Then you add until you get hum. Guess what you then deal with the problem, which probably means ungrounding that component.
It also suggest plugging everything into one power strip. This is in effect star grounding and will usually cause no problems. |
Tbg - responses in order of your questions:
No.
If you choose to play around with things electrical, you really should develop a better understanding about electrical standards and construction of the equipment you are playing with. Your assumptions may kill you. A chassis does not have to be referenced to ground if it is insulated. It's designed designed to prevent the chassis from becoming "live" if there is a ground fault. In this type of design there is no need for a ground prong. A chassis that is referenced to AC ground needs the ground connection; if it is removed and there is a ground fault, the chassis can become energized and deliver a potentially fatal shock to someone who touches it.
Isolation transformers and a properly-constructed star ground. This is what I did in my home theater. No "cheater" plugs necessary. BTW, I didn't try to pin any sarcastic labels on you. Why do want to start that kind of childish crap?
Circuit breakers will not stop an electrical fire. Circuit breakers will not prevent ground faults. |
"STUPID, STUPID" Your statement prompted my dismissal of your condecenson. One of my undergraduate majors was EE, so don't lecture me.
None of the component that I refer to have plastic housings, so forget that assumption.
"if (the grounding of the chassis) is removed and there is a ground fault" (and if the person is grounded, there can be a fatal shock. Really? Lots of ifs, which many manufacturers ignore.
Shorts or hot wires cause electrical fires. Don't breakers deal with shorts?
Given your fear of electricity, you probably should use a 12 volt system.
I see no reason to continue this tangent off the original question. |
"Shorts or hot wires cause electrical fires. Don't breakers deal with shorts?"
Thanks, good point. What is the chance of being grounded and touching the chassis when the chassis is hot anyway. I'll risk it and so does my family. |
The chance is extremely high that you are grounded. TBG's pride is hurt. RESPECT ELECTRICITY! |
Gregadd, you are right on target - Tbg's pride is hurt. |
Thank you all for your responses and advice.
(1) TBG, Gregadd, and Rex--I respect all of you replies and will investigate/research your ideas.
(2) AvGuyGeorge--I noticed no difference in sonics with the amp connected to the wall outlet vs. monster unit
(3) Darrylhifi--I don't know why some reputable companies make power cords with removable ground pins: It must be that under certain conditions the ground pins are not necessary. I think you have to be careful not to conclude that since they are removable they are not required. I'm too ignornant to know what would be appropriate electrical conditions to remove the ground pins. Will do some research here.
(4) Warnerwh--My toaster has 3 prongs. Maybe I have some "electrical ground phobia issues"?!
Gregadd has a very important point: Respect electricity. I need to understand with 100% certainty that a ground manipulation is safe, and will continue not to use cheater plug until then. Is it worth it to put yourself and family at risk? As an audiophile, I have gone though extraordinary measures to improve sonics for the quest of stereo nirvana--but we all have to be careful and knowledgeable about the electronics.
Respect Electricity.
Thanks again,
Rob |
You are right, I am a very prideful guy. I am off to lick my wounds. LOL. |
Just curious? Why don't the RCA interconnects (cables) ground one piece of equipment to the next piece of equipment, and so on...If you have a power cord, say the amp, utilizing three prongs, into a proper electrical circuit, why won't the other components ground all togethere?
Regards,
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They are; this is why you get ground loops. Sometimes, however, the chassis is not grounded to neutral or to anything. |
Quincy, the interconnects do provide a ground path from one component to another. This ground path is a low-voltage, low-current signal ground though - it is not designed for nor intended to be a safety ground for high-voltage, high-current AC power.
Electricity takes the path of least resistance. If you (or your spouse, or your child, or your pet) offer a better ground path than an RCA signal ground, guess which path a chassis leak will take? :-( |
I just plugged my Sirius satellite radio home dock into my AC Enhancer via a cheater plug because it didn't accept the three prong plug. Do I need to run a wire from the cheater plug to the ground screw on the AC Enhancer? And how long do you think before my house burns to the ground?
Sorry, I couldn't resist the second question after reading this thread. But, I would really like a sirius answer to the first question. |
Ldatlof, yes I am surprised that Rex even has electricity in his house. |
Ldatlof - the only Sirius home dock I know of is the Audiovox, and it uses a wall-wart power supply - no AC fed to the unit. In all siriusness, if you're using an AC Enhancer on a wall-wart, your house has already burned down, and you were in it.
Tbg - your obviously fragile and still-bruised ego is showing. |
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Easy explanation - you posted an attempt at a snide remark, aimed solely at me. Apparently your little feelings are still hurt. |
Hi Rex. It is an audiovox home dock as you have surmised.
I am ready for some more abuse. What's a wall-wart power supply? I admit that I don't know much about electricity, but why does it come with a three pronged plug that you are supposed to plug into the wall if no AC is fed to the unit. I have it plugged in to the AC Enhancer so that everything turns on/off at the touch of one button.
As you can see my house hasn't burned down - yet. |
Wall-wart = "A small power-supply brick with integral male plug, designed to plug directly into a wall outlet; called a wart because when installed on a power strip it tends to block up at least one more socket than it uses...."
So now that I know what a wall wart is I can unequivocally say that the Audiovox Sirius Home Dock does not come with a wall-wart. The power cord has a standard three prong plug on one end and a mini jack type at the other. In the middle there is a brick which I guess can be called a wart. But you can't plug it into a wall.
So Rex, my question still stands. Is the home dock grounded when plugged into the AC Enhancer via a cheater plug? Tbg says no, what say you? |
All depends on whether the plug going into the Sirius is at 12 volts or 120 volts. I have no idea. It takes about 32 volts for current to flow through your body, so a 12 volt wire under no circumstances can hurt you. If the body of the Sirius is non-conductive, again unless you put a wire into it while standing in water on a concrete floor, you again will be beyond danger. If it is 120 volts presented to the Sirius, it has a metal body, you are grounded, and somehow the case is charged at 120 volts, you could be in danger. Incidentally, if you use a cheater plug and ground it grounding wire to the outlet, your circuit breaker would immediately open in the event of a charged body of the Sirius.
Rex strikes me a unduly concerned about the grounding wire to components. Underwriters Labs insists on grounded components with metal bodies, but few major manufacturers of front end audio components bother to ground their chasses, because of the ground loop problem thus introduced. |
thanks tbg. it has a 12V output and is made of plastic. |
Ldatlof - the "brick" performs the same function as a wall-wart. It takes AC in, puts DC out. It is an outboard power supply.
Since the power supply supplies DC through the mini-plug connector that goes into the dock, there is no AC current in the dock. So, it was never grounded to your house AC system in the first place. With a cheater plug in place, the outboard power supply is not grounded for sure. Whether is is going to cause a problem or not, I don't know because I've never looked at the inside of the PS. Usually though, there is a reason why earth ground is connected.
Look in your manual. Does it say something like, "this product must be plugged into a properly grounded outlet?" |
Greetings!
I have read this thread with interest, and I am no closer to solving my ground loop issue.
Now, I don't want to appear overly stupid, but I thought electronics was an exact science based on math and physics. By reading this thread, I get the opposite impression.
So what IS the best way to eliminate a ground loop? Cookbook advice is always welcome. Telling me to isolate a component, for example, does not tell me how to carry out that procedure. Remember I don't have multiple degrees in electrical engineering plus an electrician's license.
The system in question has the following components:
Proceed AMP 5 (five channel amplifier)
Proceed AVP (five channel preamp)
Sony DVD player
Muse Model 18 powered subwoofer
Martin Logan Ascent loudspeakers
When the Muse Model 18 was connected between the amp and preamp using RCA ICs, a ground loop condition occurred. I tried cheater plugs on the power cords of the AMP 5 and the Muse Model 18. The hum was reduced, but not eliminated.
When I removed the Proceed AVP and the Sony DVD player and used a Klyne System 7 preamp plus a Musical Fidelity CD player while still using the Muse Model 18, there was no hum at all.
I would like to be able to use the Proceed gear, the Sony DVD player, and the Muse Model 18 to watch movies.
Any help you can provide would be appreciated.
Regards,
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Artar1 -
Give me some additional information:
1. List the components that have a three-prong grounded power cord, including the substitutes.
2. Are you using dedicated circuit(s)?
3. Are you using a power conditioner? If so, which model?
4. Are all devices plugged into one circuit, or into more than one circuit?
5. Are you using aftermarket power cords? If so, which models, and on what gear? If you are not, please tell me what the wire gauge of each of the three-wire cords are. It will be embossed on the cord jacket. |
Rex, On your question #1 please bear in mind that most Japanese products come with three prong plugs but few have the ground attached to anything. Many don't even have a third, ground connector at the unit.
Artar,
I recommend the following procedure to at least identify the culprit.
1. disconnect everything except the amp to speaker wires. Put shorting plugs into your main amp and turn it on. If you have no hum, the culprit is not the amp.
2. Connect the preamp to the amp after removing the shorting plugs. Turn the preamp on and then the amp. If you have no hum, neither are culprits.
3. Plug in one front end device. If you have no hum, with it active, it is not the culprit.
4. When you add something that causes hum, it is the culprit. It is possible that it is that unit's interconnects, so try others. Also it may be the only grounded front end device. Try a cheater plug. If the hum does not go away, try reversing the cheater. If none of this works, you have a problem with that device.
If the hum goes away with the cheater, which will typically be the case, you have an issue--do you need it grounded? Rex would answer one way and I another.
You might also find that grounding the unit to the amp may cause the hum to go away. Also a resister on the ground may solve the problem. |
Artar1 - just FYI, if you have your equipment plugged into multiple circuits, Tbg's suggested procedure will not be of any help. |
Rex,
Thank you very much for responding to my post. I appreciate it!
Let me try to answer your questions the best I can.
1. List the components that have a three-prong grounded power cord, including the substitutes.
All components have a three-prong plug on their power cords except the Sony DVD player. So the Proceed AMP 5 amp, Proceed AVP preamp, Klyne System 7 preamp (substitute preamp), Musical Fidelity Nu-Vista 3D CD player (substitute CD player), and Muse Model 18 subwoofer all have a three-prong power cord. The Sony DVD player has only a two-prong power cord. I will check to make sure, however.
2. Are you using dedicated circuit(s)?
No. In the future I will, but not now.
3. Are you using a power conditioner? If so, which model?
No power conditioner per se; however, the Proceed AVP preamp, Klyne System 7 preamp (substitute preamp), and Musical Fidelity Nu-Vista 3D CD player (substitute CD player) are all plugged into a Monster Cable HTS 2000 power strip/line filer. The AMP 5 is plugged directly into a wall outlet.
4. Are all devices plugged into one circuit, or into more than one circuit?
I will have to check the breaker box when I return home tonight. But its my guess that all AC outlets could be on the same line. I am not sure about this.
5. Are you using aftermarket power cords? If so, which models, and on what gear? If you are not, please tell me what the wire gauges of each of the three-wire cords are. It will be embossed on the cord jacket.
I will have to check the gauge of all the power cords when I return home. I am using stock power cords on all components except the Klyne preamp, which uses a Monster Cable Powerline 300. In the near future, I will be replacing all the other stock power cords with Element Cables ElementCord, which uses 10 AWG wires.
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Tbg,
Thanks for responding to my post too.
I believe the culprit is the Muse Model 18, but it seems to work fine when the Klyne preamp and Musical Fidelity CD player are used instead of the Sony DVD player and the Proceed AVP.
1. Disconnect everything except the amp to speaker wires. Put shorting plugs into your main amp and turn it on. If you have no hum, the culprit is not the amp.
The main amp (Proceed AMP 5) does not hum, and it worked fine until the Muse Model 18 was plugged into the system.
2. Connect the preamp to the amp after removing the shorting plugs. Turn the preamp on and then the amp. If you have no hum, neither are culprits.
The Proceed AVP preamp also worked fine until the Muse Model 18 was plugged into the system.
3. Plug in one front-end device. If you have no hum, with it active, it is not the culprit.
The front-end device (Sony DVD player) also worked fine before the Muse was inserted. This leads me to believe that the Muse may be on another circuit from the other equipment and is, therefore, creating a situation in which there are multiple grounds.
4. When you add something that causes hum, it is the culprit. It is possible that it is that unit's interconnects, so try others. Also it may be the only grounded front-end device. Try a cheater plug. If the hum does not go away, try reversing the cheater. If none of this works, you have a problem with that device.
Using another set of interconnects is not an option. I am using two 12-foot pairs of Transparent Audio MusicLink Plus ICs that cost me $1,200. I can try reversing the cheater plug that I am using on the Muse to see if that suggestion works. Prior to installing the Muse Model 18 in my system, I had sent it back to the factory to be completely checked out. It was given a clean bill of health.
You might also find that grounding the unit to the amp may cause the hum to go away. Also a resister on the ground may solve the problem.
How do I ground a component to the main amp and how do I place a resister on the ground?
Thanks
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Rex,
Here is the missing information that you had requested in an earlier post:
All components are on the same 15-amp circuit.
The gauge of all power cords is as follows:
1. Proceed AMP 5 = 14 AWG
2. Proceed AVP = 18 AWG
3. Monster Cable HTS = 14 AWG
4. Sony DVP-S7700 = 18 AWG (two prongs)
5. Musical Fidelity Nu-Vista 3D = 16 AWG
6. Muse Model 18 Subwoofer = 14 AWG
7. Acoustic Research Power Strip (grounded) = 14 AWG
The Muse Model 18 and the Martin Logan Ascent loudspeakers are plugged into the AR power strip, which does offer some AC line filtering.
Thanks in advance for your help.
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Artar1 - I sent you an email! Easier to tackle this offline. |
