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How dangerous is lifting the ground on a source component?

rebbiputzmaker

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Forgive me if I always find this ground discussion Amusing. In the 60s grounding was not even a thing, started in the 70s pretty much mandatory after that. Of course it is safer but people lived fine prior to it also. If you do lift a ground because of hum etc just be careful don’t jump in the tub with CD player.
 

JEarle

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I know that where I live (Minneapolis) replacing old two prong, ungrounded outlets with GFCI's is to code in pre-existing installations. That seems to indicat that plugging in a device that is designed to be grounded to an ungrounded outlet is safe (enough). So by extension, using cheater plug into a GFCI outlet is safe (enough), maybe not ideal, but....?
 
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antcollinet

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Forgive me if I always find this ground discussion Amusing. In the 60s grounding was not even a thing, started in the 70s pretty much mandatory after that. Of course it is safer but people lived fine prior to it also. If you do lift a ground because of hum etc just be careful don’t jump in the tub with CD player.

You don't think it likely that grounding was introduced because...you know... people were being killed by electrical faults?
 

Doodski

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In the 60s grounding was not even a thing, started in the 70s pretty much mandatory after that.
I've detected very small current flow electrocution from old gear with a bad ground or no ground at the chassis. Think like ~40-70 VAC at low current. Connect a RCA and voila no shock.
 

DonH56

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Just thinkin out loud. Seems like lifting the ground would be safe if you use a GFCI. And cheap.

"The GFCI monitors the electric current in the hot line and the neutral line (see Figure 1). When these two currents are equal operation is normal and there is no ground fault. However when these two values become unequal by as little as 4-5 mA another path to the ground (ground fault) may be present, in this case the GFCI will open (with a response time of 1/30th of a second) thereby preventing electric shock to a person. A GFCI has a reset button to restore it to original conditions after it has opened the circuit, as well as a test button to ensure it is functioning properly.[3]"

Comments?

An opportunity to get rich selling audiophool GFCIs, if people will spend $100 on a regular outlet (http://www.enjoythemusic.com/magazine/equipment/0114/audiophile_ac_outlets.htm) think how much you can soak them for a an outlet that "gets rid of ground loops" etc.

The problem is that, without a safety ground, the current can be equal and yet the chassis be at 120/240 V, usually undesirable.

Having been shocked myself, seen many others shocked and one or two die as a result (plus a slew of cattle killed at a dairy farm when a safety ground was broken and a transformer shorted), I will continue to advocate for safe approaches to resolving ground loops. I have plenty of other stupid ways to die. Running stop signs is safe enough, until it's not.
 

rebbiputzmaker

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You don't think it likely that grounding was introduced because...you know... people were being killed by electrical faults?
Not really no. People were not being killed like that. Obviously code became better and made safer but people lived perfectly fine prior to grounding. In fact electronics used much higher voltage using vacuum tubes. Shock was relatively rare. People were cognizant of the risk. people were not retarded. Maybe society has gotten stupider? Imo natural gas used in homes is more dangerous than electricity. People seem relatively unconcerned about cooking and heating in their homes.
 
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antcollinet

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Standards organisations rarely go out of their way to fix problems that don't exist.
 

DonH56

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People were fine before safety belts. I wear mine anyway.

There are far more electrical devices in today's home than decades ago. I do not think people are generally retarded, but ignorant of the danger.

I suspect shock is relatively rare today, just as in the past, but choose to minimize my risk where I can. I do plenty of other stupid things that could get me killed so it's not like I am overly paranoid, but skipping the cheater plugs seems like a simple counter to a momentary lapse of reason.
 

escksu

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I also had to lift the ground of my source (computer connected to receiver with HDMI cable) to get rid of some nasty humming, even though all analogue connections are balanced XLR (Nvidia GPU to Marantz AV7706 to Hypex NC502MP based amps was my hum chain). I’m not overly worried about lifting the PC’s ground though since I have modern GFCI breakers, and the PC is still grounded through the HDMI cable.

The issue with XLR is that pin 1 gound is connected on both sides of the connector (default configuration). So, to avoid this you will need to disconnect pin 1 from the destination.
 
OP
tmtomh

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People were fine before safety belts. I wear mine anyway.

There are far more electrical devices in today's home than decades ago. I do not think people are generally retarded, but ignorant of the danger.

I suspect shock is relatively rare today, just as in the past, but choose to minimize my risk where I can. I do plenty of other stupid things that could get me killed so it's not like I am overly paranoid, but skipping the cheater plugs seems like a simple counter to a momentary lapse of reason.

My situation is quite low-risk: the Oppo is in a non-metal cabinet, on carpet, in a dedicated office/listening room that can be closed and locked. Only my wife and I live in our house, and she never uses the stereo (or comes in the room unless I'm in it, for that matter). I operate the Oppo exclusively via its remote, and the part of the disc drawer where one places the disc is plastic. The home is new-construction, and we had the house built ourselves and worked directly with the electrician, so no cheapo "builder's special" wiring done by a person of unknown qualification level.

Even with all that, I would not turn on the Oppo, let alone use it regularly, with a ground-lift plug. The chances of a problem are minimal - but the scale and consequences of the problem if it should happen are potentially catastrophic. Not worth the risk IMHO.
 

rkbates

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Just thinkin out loud. Seems like lifting the ground would be safe if you use a GFCI. And cheap.

"The GFCI monitors the electric current in the hot line and the neutral line (see Figure 1). When these two currents are equal operation is normal and there is no ground fault. However when these two values become unequal by as little as 4-5 mA another path to the ground (ground fault) may be present, in this case the GFCI will open (with a response time of 1/30th of a second) thereby preventing electric shock to a person. A GFCI has a reset button to restore it to original conditions after it has opened the circuit, as well as a test button to ensure it is functioning properly.[3]"

Comments?

An opportunity to get rich selling audiophool GFCIs, if people will spend $100 on a regular outlet (http://www.enjoythemusic.com/magazine/equipment/0114/audiophile_ac_outlets.htm) think how much you can soak them for a an outlet that "gets rid of ground loops" etc.
Having investigated lots of electrical accidents, there are (broadly speaking) two categories:
1) How did that person survive for so long? Darwin catches up eventually.
2) How did so many exceptionally rare and unexpected events coincide at this exact time and place?
Lots of safeguards need to fail to get hurt. Removing an earth is a safeguard. The fact that there is hum in the signal path could mean that something has failed or is failing (may or may not be related to the mains). GFCIs are not the silver bullet - I would not trust my life to one.
 

rebbiputzmaker

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People were fine before safety belts. I wear mine anyway.

There are far more electrical devices in today's home than decades ago. I do not think people are generally retarded, but ignorant of the danger.

I suspect shock is relatively rare today, just as in the past, but choose to minimize my risk where I can. I do plenty of other stupid things that could get me killed so it's not like I am overly paranoid, but skipping the cheater plugs seems like a simple counter to a momentary lapse of
Do you have any devices that aren’t grounded at home? What about simple chargers or adapters? Granted it is safer but you talking about really such a minimal risk, I just cannot see a real reason to worry? The seatbelt analogy is not totally fair IMO. How about the seatbelt analogy if you’re only traveling 2 mph in the car then maybe I could give it to you. The energy used by a device in question also is a consideration when talking safety. Low power devices are less concerning than high power etc.
The environment matters also that’s why GFI outlets are always present in kitchens and bathrooms where there is water which presents an additional safety concern in electrical appliance use.
 

DonH56

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Do you have any devices that aren’t grounded at home? What about simple chargers or adapters? Granted it is safer but you talking about really such a minimal risk, I just cannot see a real reason to worry? The seatbelt analogy is not totally fair IMO. How about the seatbelt analogy if you’re only traveling 2 mph in the car then maybe I could give it to you. The energy used by a device in question also is a consideration when talking safety. Low power devices are less concerning than high power etc.
The environment matters also that’s why GFI outlets are always present in kitchens and bathrooms where there is water which presents an additional safety concern in electrical appliance use.

Many but they are certified as such; see earlier posts from others about double-insulated devices. Those devices are not the problem. The problem arises when a required safety ground is bypassed. As I have repeatedly said, I have felt and seen the consequences up to and including death, so prefer to avoid it even if "minimal".

The power the device uses is essentially irrelevant for this case; it only takes a few mA to kill, and in any event we are talking about a fault condition and not normal operation. The environment is also irrelevant. The fault causes an exposed chassis (exterior) to reach line potential and there are many ways to complete the circuit, with or without water around. The death of a friend's father involved holding one piece of equipment and touching another in a dry shop.
 
OP
tmtomh

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@tmtomh,

Use a balanced cable from the EQ to the power amp which has XLR's as I may assume, this is an unbalanced RCA to balanced XLR adapter cable which must look like this:
RCA Center goes to inner conductor (+) of the balanced cable,
RCA Shell goes to inner conductor (-) of the balanced cable as well as the shield of the balanced cable.
By this, the offending mains balancing current is diverted away from the signal path wires, causing way less -- if not totally removed -- hum/buzz.

Combine this with moving the EQ Unit (probably a class-II -- 2-prong -- mains device) right on top of the Oppo (which is Class-I) and connect them with the shortest RCA cables you can find, preferably ones with a thick and solid shield construction.

That should suffice to fix that little issue. If not, please report back for further assistance which then might require more details to be checked. Do you have a good multimeter than can display true RMS AC voltages and measure resistances, and some soldering skills?

I have to confess, I thought this would not have any impact. But I did try it. I honestly don't know if the particular RCA-XLR cables I ordered are wired correctly (I got WBC/"World's Best Cables" off Amazon because it would arrive quickly and I could therefore test it quickly).

The cables have not totally eliminated the hum - but they have definitely had a positive effect - thanks! After connecting them, I ran my previous test: all components connected to each other, turn on the power amp with the EQ plugged in to AC but turned off and the Oppo unplugged from AC. No hum, just as before. Then I plugged in the Oppo but did not turn it on. Previously this immediately would produce hum in the speakers. Now the speakers remain totally silent when I plug in the Oppo - progress!

When I turn on the EQ, I hear a little bit of the EQ's self-noise in the form of low-level hiss if I put my ear about 6-12 inches away from the speaker (I posted about this in a thread about Hypex and Purifi amps - my Purifi amp is so quiet that I now hear the upstream components' self-noise added to the signal when I power them on). But still no hum.

When I turn on the Oppo and it fully boots up, I do unfortunately hear hum in the speakers. However, it is significantly reduced from before. If I turn my head sideways to the speaker, so that my ear opening is directly facing the speaker's drivers, I can hear the hum from 6-8 inches away for the L speaker and about 12 inches away for the R speaker. (I am guessing this small difference reflects a tiny difference in the amplitude of the hum, perhaps related to internal wiring arrangement in one or more of the components). If I turn my head to normal position so I'm looking at the speaker, or if I back away from that 6-12 inch range, I lose track of the hum and can't hear it anymore. And so from my listening position, which is about 8-9 feet/2.5-3M away, I can't hear anything, which of course is what is important.

I am still testing to see if the hum increases when I've been playing music for awhile (maybe temp related somehow?). And I have not yet had a chance to listen at night (when human hearing gets more acute), but so far this is encouraging.

Most importantly, the Hum-X is still out for delivery to me today, so I haven't yet had a chance to try that. Since these cables have had an effect, though, it increases my cautious optimism (however rationally or not) that the Hum-X also will have a positive impact.

Two final questions, for you, @DonH56 , and anyone else who has a sense of this:

1. Would it have any potential additional benefit to also install RCA-XLR cables between the Oppo and the EQ? I would guess No, since the XLR-RCA connection would be going in the opposite direction as the EQ-amp connection and therefore would not have the same benefit. But as noted previously I'm kind of an idiot when it comes to grounding and similar electrical basics so I really have no idea.

2. Similarly, my plan is to connect the Oppo to the Hum-X since it's the obvious choice - it's the only low-current, 3-prong component in the chain. But would it be worth trying the Hum-X (or a 2nd Hum-X) with the EQ too? It's 2-prong, floating, but since I don't know exactly how the Hum-X works, I wonder if there's any possible benefit since the ground hum is traveling through the EQ to get to the amp and speakers. Again, I doubt this would be of any use but I really don't have any expertise in this area, so...

I'm glad I feel I can once again listen to my system without feeling like I'm hearing a tiny bit of that hum during the silence between tracks, but I would definitely like to basically eliminate it altogether if I can. And this is definitely getting me into gear to prep my spare Oppo 205 for sale to make a dent in my Genelec Endgame Savings Fund. :)

Thanks!
 
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levimax

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I have to confess, I thought this would not have any impact. But I did try it. I honestly don't know if the particular RCA-XLR cables I ordered are wired correctly (I got WBC/"World's Best Cables" off Amazon because it would arrive quickly and I could therefore test it quickly).

The cables have not totally eliminated the hum - but they have definitely had a positive effect - thanks! After connecting them, I ran my previous test: all components connected to each other, turn on the power amp with the EQ plugged in to AC but turned off and the Oppo unplugged from AC. No hum, just as before. Then I plugged in the Oppo but did not turn it on. Previously this immediately would produce hum in the speakers. Now the speakers remain totally silent when I plug in the Oppo - progress!

When I turn on the EQ, I hear a little bit of the EQ's self-noise in the form of low-level hiss if I put my ear about 6-12 inches away from the speaker (I posted about this in a thread about Hypex and Purifi amps - my Purifi amp is so quiet that I now hear the upstream components' self-noise added to the signal when I power them on). But still no hum.

When I turn on the Oppo and it fully boots up, I do unfortunately hear hum in the speakers. However, it is significantly reduced from before. If I turn my head sideways to the speaker, so that my ear opening is directly facing the speaker's drivers, I can hear the hum from 6-8 inches away for the L speaker and about 12 inches away for the R speaker. (I am guessing this small difference reflects a tiny difference in the amplitude of the hum, perhaps related to internal wiring arrangement in one or more of the components). If I turn my head to normal position so I'm looking at the speaker, or if I back away from that 6-12 inch range, I lose track of the hum and can't hear it anymore. And so from my listening position, which is about 8-9 feet/2.5-3M away, I can't hear anything, which of course is what is important.

I am still testing to see if the hum increases when I've been playing music for awhile (maybe temp related somehow?). And I have not yet had a chance to listen at night (when human hearing gets more acute), but so far this is encouraging.

Most importantly, the Hum-X is still out for delivery to me today, so I haven't yet had a chance to try that. Since these cables have had an effect, though, it increases my cautious optimism (however rationally or not) that the Hum-X also will have a positive impact.

Two final questions, for you, @DonH56 , and anyone else who has a sense of this:

1. Would it have any potential additional benefit to also install RCA-XLR cables between the Oppo and the EQ? I would guess No, since the XLR-RCA connection would be going in the opposite direction as the EQ-amp connection and therefore would not have the same benefit. But as noted previously I'm kind of an idiot when it comes to grounding and similar electrical basics so I really have no idea.

2. Similarly, my plan is to connect the Oppo to the Hum-X since it's the obvious choice - it's the only low-current, 3-prong component in the chain. But would it be worth trying the Hum-X (or a 2nd Hum-X) with the EQ too? It's 2-prong, floating, but since I don't know exactly how the Hum-X works, I wonder if there's any possible benefit since the ground hum is traveling through the EQ to get to the amp and speakers. Again, I doubt this would be of any use but I really don't have any expertise in this area, so...

I'm glad I feel I can once again listen to my system without feeling like I'm hearing a tiny bit of that hum during the silence between tracks, but I would definitely like to basically eliminate it altogether if I can. And this is definitely getting me into gear to prep my spare Oppo 205 for sale to make a dent in my Genelec Endgame Savings Fund. :)

Thanks!
Ground loops are funny things and sometimes trying to figure out exactly which component is doing what is not helpful as it is the "connected system" that is causing the issue and how it all interacts is often complicated and non-intuitive. I hope the "Hum-X" works for you but I have never had any luck with them. I am using a DIY tri-amp system with analog active crossovers with many possibilities for ground loops. For me an isolation transformer always works and results in a dead quiet system https://www.jensen-transformers.com/product/ci-2rr/ . Good luck.
 
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tmtomh

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Ground loops are funny things and sometimes trying to figure out exactly which component is doing what is not helpful as it is the "connected system" that is causing the issue and how it all interacts is often complicated and non-intuitive. I hope the "Hum-X" works for you but I have never had any luck with them. I am using a DIY tri-amp system with analog active crossovers with many possibilities for ground loops. For me an isolation transformer always works and results in a dead quiet system https://www.jensen-transformers.com/product/ci-2rr/ . Good luck.

Thanks! That looks like an interesting device and I can see how it would stop the hum in its tracks. In one sense it's a more direct approach because it directly intervenes in the signal path. On the other hand it's a less direct approach because it doesn't directly intervene in the grounding situation that seems to be causing the problem.

It looks like a new unit runs about $200. That's above the sub-$100 "I'll just quickly order one and see if it works" threshold that led me to pull the trigger on the Hum-X and those XLR-RCA cables. And the interconnects and Hum-X don't insert anything new into the signal path, which is my preference if possible. But if the Hum-X does nothing, and the acceptably low level the hum is now at with the XLR-RCA cables increases for some reason, I will take another look at that Jensen unit you've recommended. Thanks!
 
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Cbdb2

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People were fine before safety belts. I wear mine anyway.

There are far more electrical devices in today's home than decades ago. I do not think people are generally retarded, but ignorant of the danger.

I suspect shock is relatively rare today, just as in the past, but choose to minimize my risk where I can. I do plenty of other stupid things that could get me killed so it's not like I am overly paranoid, but skipping the cheater plugs seems like a simple counter to a momentary lapse of reason.

????

Many Americans understand the lifesaving value of the seat belt – the national use rate was at 90.3% in 2020. Seat belt use in passenger vehicles saved an estimated 14,955 lives in 2017.
 

Cbdb2

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Having investigated lots of electrical accidents, there are (broadly speaking) two categories:
1) How did that person survive for so long? Darwin catches up eventually.
2) How did so many exceptionally rare and unexpected events coincide at this exact time and place?
Lots of safeguards need to fail to get hurt. Removing an earth is a safeguard. The fact that there is hum in the signal path could mean that something has failed or is failing (may or may not be related to the mains). GFCIs are not the silver bullet - I would not trust my life to one.

But people trust there lives to them everyday in every bathroom.
 
OP
tmtomh

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Hum-X just got delivered (branded as a Morley Hum Eliminator but looks identical and it appears Ebtech and Morley are the same company and that the Morley device is sometimes branded as the Hum Eliminator and sometimes as the Hum Exterminator).

It works! Hum is entirely gone - ear up against the speaker, nothing.

Thanks for the recommendation of this device, as well as for the recommendation of the RCA-XLR cables, which also helped - and for the tremendous amount of educational info along the way!
 

restorer-john

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Double insulation (class 2 insulation system) means that there are effectively two layers of certified basic insulation between dangerous voltages and any touchable metal parts, or enclosure openings.

One of these "layers" can also be a clearance distance of at least 5.5mm, and a clearance of 8mm is considered double insulation (Note these distances must be maintained under worst case tolerances - so for example if one of the layers is the insulation around a wire, then it must not be possible for any part of that wire to get closer than 5.5mm to the chassis - even when "pulled".

It is not necessary to worry about audio ground connections between equipment on a class 2 device, because if another connected device is class 1 - then its earth connection will prevent any dangerous voltages appearing on the interconnect.

Double insulation (class ii) is just a cop-out and not remotely as safe as a correctly earthed device. It's been watered down over the years to the point where I see multiple flaws inside most pieces of inexpensive gear that could easily render the items highly unsafe in predictable failure scenarios.

My attitude is, if the item has ANY exposed metal than can be touched, the item should be safety earthed. Period.

The double insulation plague in audio started in the late 1970s, prior to that, pretty much all HiFi was correctly earthed. A lot of gear coming into Australia in the 1970s and 1980s had to be rewired here to our standards. In fact several HiFi brands had perforated trapdoors in the packaging, that you hinged out, changed the plug and the voltage switch and folded the flap back- all without removing the product from the package.

Ironically, Pioneer Australia 'created' hum problems in some high end HiFi amplifiers by rewiring multivoltage class ii (double insulated) products with an Australian compliant three core earthed lead. In those cases, yes, the earth lead shouldn't have been there.

Double insulation gave lazy designers an 'out' in terms of hum related issues on the typical single ended (RCA) designs of the time.
 
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