Is grounding with RCA is safe?

Don't do it! You are creating a ground loop! Your gear is best grounded through each component's ac cable!

The only way that occurs to me in which that might be hazardous to the equipment is in the very unlikely event that an insulation failure develops within a component, resulting in the AC line voltage being applied to the chassis of the component and from there via the AC safety ground connection and the wires you have installed to the internal circuit grounds of the components, during the brief amount of time it would take the breaker to trip.

However, as Roberjerman indicated you are making the system very susceptible to ground loop issues. In effect what you are most likely doing (depending on the designs of the components) is connecting the internal circuit ground of each component to the chassis of that component and to the chassis of every other component in the system. Thereby in effect changing the designs of the components, as well as the ground paths between them.

While you have found the results of those changes to be subjectively preferable to you, you have therefore most likely compromised the accuracy of the system.

Regards,
-- Al

I see. Thank you all for your inputs. 

I searched online and learn that ground loops can destroy audio gears in long run. Is it true?

I still have a question regarding your reply: 
"In effect what you are most likely doing (depending on the designs of the components) is connecting the internal circuit ground of each component to the chassis of that component and to the chassis of every other component in the system"

I check the ground box from Entreq. It looks like to me that they do the same thing.

Could you help shed some light on this?

I have to apologize for my ignorant questions because I am a dumb in electricial area.

Thank you.

I still have a question regarding your reply:
"In effect what you are most likely doing (depending on the designs of the components) is connecting the internal circuit ground of each component to the chassis of that component and to the chassis of every other component in the system"

I check the ground box from Entreq. It looks like to me that they do the same thing.

Could you help shed some light on this?

The internal circuit grounds of most components are connected to the ground sleeve of their RCA connectors. And since the components apparently have three-prong power plugs, the safety ground prong on those plugs is presumably connected to the chassis of the corresponding component.

So since you have connected the ground sleeve of an RCA connector to the safety ground pin on the power plug of each component, and the safety grounds of all of the components are connected together via the outlets and the associated AC wiring, you have most likely connected both the circuit grounds and the chassis of all of the components together.

I have no knowledge of Entreq products, but if in fact they do the same thing I personally would not want to use them.

I searched online and learn that ground loops can destroy audio gears in long run. Is it true?

I can’t envision a means by which a ground loop could cause damage, other than in the very unlikely scenario I described in my previous post. A ground loop could, of course, have adverse sonic consequences, and degrade the accuracy of the system. Which may or may not be subjectively preferable, however.

Regards,
-- Al

I wouldn't say it is unsafe, per se, but many designers deliberately lift the ground to prevent noise issues. Seeing a 100 Ohm resistor between the chasis, which is directly attached to the AC ground, and the signal ground is quite common. 
The quietest systems I've ever heard completely isolated the signal ground from the AC ground, preventing ground loops altogether.

I would not encourage anyone to start hacking this way.

In most components the circuit ground is directly connected to the chassis. And the chassis is connected to power cord ground. Pretty sure all common ground amplifiers are set up that way. You would not want to try your RCA trick with a non common ground amp.

So what you are proposing technically not make any difference, but anything goes with audio. According to the books what you are doing should make the system sound worse. You are supposed to ground everything in a component to a single point on the chassis via a "star ground". Grounding to different points is supposed to do bad things to the sound.

I would take a peek inside and make sure the circuit ground is connected to the chassis somewhere. The power cord ground should be connected to the same point. Then even though it goes against conventional wisdom......if your system sounds better go for it.

In most components the circuit ground is directly connected to the chassis.

I believe that is not true. And certainly, IMO, a **good** design will not connect circuit ground and chassis directly together, as it invites ground loop issues.

As Erik indicated, many designs have a resistor connected between circuit ground and chassis, and many others go even further in isolating them from each other. I know, for example, that circuit ground and chassis are not connected together in most or all Audio Research, Ayre, and Atma-Sphere designs, among others.

Regards,
-- Al

What you are doing is perfectly safe. The outside is ground anyway. Its real easy, with tube gear anyway, to look inside and see the one wire coming from the center of each RCA and going straight to the input selector. Only one wire. Don't take my word for it. Look and see. One wire. That's the pin, that's the signal, that's positive. That's why its insulated, and routed the way it is, away from noisy bits like transformers. That's why they lay them out the way they do.

Notice the outside of each RCA. They are not wired individually. They do not go to the input selector. On many amps they connect to a bus bar. Follow that wire, which notice is not insulated, it will at some point complete the circuit by being connected to ground. They may all come together at one point, I don't know, have only looked into and modded a few so there may be some exceptions. 

When there are you can be sure its for sound quality not safety. Mainly the problem is the way electricity works, running a signal through a wire generates a magnetic field around the wire proportional to the signal. While at the same time every magnetic field crossing a wire induces a voltage in that wire proportional to the field. This is how electricity is generated, be it in a Koetsu cartridge or Hoover Dam, and this is how transformers work too. And antennas. Same deal.

So if you're hearing an improvement that kind of makes sense. What you're doing is providing a more direct route to ground taking that one small part of the problem out of the amp. A little less is a little less and if you hear it you hear it. 

Count yourself lucky. The ground loop guys are right. Only thing they're missing is its a crap shoot. One guy does everything right, winds up with hum and hunting down a ground loop anyway. Another guy (that would be you) deliberately wires extra grounds which one would think ought to hum like crazy, and instead it actually sounds better. Go figure.

I use these from Gutwire: http://gutwire.com/?page_id=1334

They connect via your RCA, XLR, spade or Pin safely to an outlet. I've had mine for over a year and no problems whatsoever.

All the best,
Nonoise

The following thread will be of interest:

https://forum.audiogon.com/discussions/a-new-ground-benefits-of-introducing-the-synergistic-research-active

Some excerpts:

Atmasphere 6-27-2017
I did a survey of a number of grounding systems by interviewing the owners and having them do a few tests (as best as I can make out, these were similar to the SR, but none of them were SR units).

What I found was that in audio systems where a grounding system made an improvement, universally there were also bugs in the way that the associated audio equipment was grounded, which is why the grounding boxes were helping.

Just my opinion of course, but if the manufacturers of the various products (amps, preamps and the like) in those audio systems were to fix the bugs in their products, the result would be even better and at worst just as good as the (IMO rather expensive) grounding system add-ons.

My conclusion was that if a grounding box was helping, that was an indication that the associated equipment had design flaws in their grounding implementation.

Atmasphere 6-28-2017
All it takes is one component to short out the grounding scheme on the other equipment.

How it works is, the chassis of the equipment should be grounded to the ground pin of the AC cord which in turn is grounded by the house wiring. There is no current on this connection....

... The circuit ground of the amplifier, preamp or whatever is **not** connected to the chassis in a proper setup but is instead ’floated’ at ground potential by a simple circuit which might simply be a resistor or resistor/diode arrangement. In this way ground loops between equipment are prevented and the chassis is allowed to act as a shield while not also acting as a ground return.

If only one piece in the system has the circuit and chassis be the same thing, then its connection to the rest of the system will compromise the grounding of the rest of the system. Now you have to do something about it and that is what these grounding block thingys do- at a tremendous price though, as a better solution would be to simply have the offending piece repaired by the manufacturer.

Almarg 6-28-2017
Ralph, thanks. That all makes sense from a technical standpoint, as far as I am concerned. Question: Could similar adverse effects occur to an audible degree if rather than circuit ground and chassis ground/AC safety ground being connected directly together in one or more of the components in a system, they are instead connected together through a resistor whose value is simply too low? For example, I’ve seen in some ARC designs that resistors as low as 10 ohms are used for that purpose.

Atmasphere 6-28-2017
Hello Al,

The resistor is there to prevent ground currents and often 10 ohms is enough to do the job, just as you see in the old Dynaco gear.

I like a little more myself, and its not a bad idea to place some high current diodes in opposite directions in parallel with the resistor. In this way if a component is damaged and places the AC line on the chassis, a fuse will blow rather than just cooking the resistor.

I’ve not played with the resistor value to see what effect it has, but it stands to reason that a value too low mitigates its use and not in a good way :)

Atmasphere 7-5-2017
If you have a DVM there is a simple measurement that will tell you if the amp/preamp/whatever is properly grounded.

With the unit unplugged and out of the system, the DVM set to the Ohms scale:

The center pin of the IEC connection (or ground pin of the AC cord) should measure a short to the chassis; IOW about 0.5 ohms or less.

If the ground of the audio input connection measures the same then you have a problem. If it seems to measure significantly higher than things are good.

If you have no connection between the chassis and the ground pin of the AC cord then the equipment can be considered dangerous and will not meet UL standards nor EU Directives (CE mark).

And note especially the second sentence quoted from the following post!

Folkfreak 10-29-2017
The [Synergistic Research] active ground block has active components inside as well as a ground connection.

... even passive ground solutions give results, consider for example the Entreq units which have no connection to the AC safety ground at all but still produce the same type of results.

ted_d (Ted Denney of Synergistic Research) 5-1-2019
The Active Ground Block SE has an Active Electromagnetic Cell similar to what is found in our PowerCell line conditioners, the non SE version does not. This (the Active EM Cell) filters high frequency noise out of ground which is significant....

... NEVER EVER plug the Active Ground Bock into anything but the wall. Do NOT plug it into a line conditioner or anything but a wall outlet otherwise you will introduce impedance and crosstalk contamination and this seriously diminishes sound quality.

Regards,
-- Al

Hello OP,

Please unplug that. Further reading will give reasons why, but unnecessary.

I would be hesitant to sound a whistle on an otherwise lively discussion, but we have essentially anonymous posters making reckless assertions having nothing to do with fact. Moreover several are only their ‘observations’, based loosely upon their personal incomplete understanding. I’m not getting into a flame war with other posters by repeating inane statements and then responding. But please unplug your contraption. No EE or state license-holder is going to suggest leaving it as a temporary solution. It’s creating more of a hazard than you think regardless of the sound. I will explain exactly what is wrong with your approach rather than point you to some roundabout explanation not based in safety, science or fact. Of course, no one can exactly diagnose your audio issue remotely. Not doing that. Don’t want you killed or anyone running around your sound room.

In terms of significance these issues are in no particular order. First, at the core, even if that idea of a ground were acceptable, you are using temporary and under-gauged wires. The RCA connectors probably a thinner gauge wire than what a normal ground ‘plug’ wire would be. The-wall ground wire is around 14 gauge (green wire). For an actual ‘ground’ you wouldn’t want moveable, unplugable pieces (RCA M/F) that could be confused with the same cables serving as interconnects. If it’s only you living with the sound room and you can always remember not to unplug ‘those’ wires, it’s still not enough. You have male to female connectors that might have oxidation or be different metals…you should have just wire, or at least soldered or crimped connectors…the ground or “a” ground is safety. In a car you don’t have to remember to turn an airbag on or off. Secondly, whatever was “solved” with approach wasn’t solved but rather relocated. You might have an offending appliance on a shared same circuit having nothing to do with your audio equipment. Additionally to that, there are EM fields everywhere on current carrying devices and a slight move of a cable or wire could have created an issue. Guitar amps can hum based upon a guitar’s proximity to the amp due to the type of pickup used. It’s not the amps fault. Even if it’s a $3,000 amp, depending on the setup it can hum and will. Single-coil pickups.

Thirdly, a “ground” is not the same as a neutral wire (or where the current goes ‘out’ from your devices). The ground is a safety belt mostly for the equipment. It can help save humans though. Conversely, GFCI’s are SOLELY meant to save humans from accidental exposure and some fire hazards but even those are not 100% and must be periodically tested. “Ground” or “Earth” in electronics is not the same as a “green ground wire” or ground hole in an electrical outlet. “Ground” in electronics is a limitless sink which would absorb any voltage so that a predictable “potential” or voltage can be provided within a design. DC, best display by household batteries do not have “ground”. They have “+” and “-“. They also don’t kill. Household batteries are nearly always limited to under 50V because larger exposures can be lethal. In your amp, you have high voltage. AC is more lethal than DC at high voltages but you wouldn’t want to touch 300V of either. Designers of electronics don’t really care or specify whether the “earth” means flow to neutral or ground. It’s nearly always neutral bolstered by a ground, but that’s that what they focus on. Someone will say, “Yeah, my service panel showed me different. I saw that all the white ‘neutral’ conductors at the bar shared a connection to the ‘ground’ bonded to my cold water pipes and a giant copper rod that cost $300 to have an electrician install before he’d put in a 200a panel for another $2,000.” That is true, but not the only story. Those “ground” connections are a last resort of protection in case there is voltage within your house and the neutral conductor to the utility is disconnected. Undischarged capacitors are an example of that. That is fact and science. They are required or rather ‘supposed’ to drain within a certain time limit but there can be older equipment or who knows what people do to hotrod their systems.

I would try to figure out what changed system-wise to isolate a component and eliminate the problem that way or you have a piece of equipment with a problem (or a wiring problem, or competing load on the same circuit…any recent wiring work?).

I remember a comment mentioning a “single” wire flowing into a selector and logically, the “ground” then must be the equipment case. There are some minimalist systems and DIY pieces that do that. You can’t have voltage without a potential between two points. HOWEVER, the voltage running through the selector to the case is 5V at most if there are small lights or its in mV if just signal. Most electronics have a relay or other mechanism to soften the transition. However, if you had the ability to interrupt the voltage from tubes to the speakers without a temporary sink, the circuit board will melt, capacitors explode because with tubes that electricity can’t be in limbo. Say if you held it in between states and there was no relay or resistor. And, it’s not the high lethal voltage in the amplification stage NEVER running through tone controls or volume or gain controls. The high voltages in any system don’t go first to the chassis and then wherever else, doesn’t matter. They ALWAYS by design return to the neutral and as a safety at some point there is a ground wire connected to the chassis, but also the ground on a 3 wire connection. There are rather cheap test device that will confirm if you still have a “good ground” at your outlet.  Tubes, solid state or not even an amp.  Same issue.  You are putting 115V or 120V in and expecting a result...which is not expected to be 120V or higher into your body or a burst of flames.

To go on, but probably the most important notion is that a ‘ground’ is the last resort. And it’s really meant to save equipment. Electricity will run through the path of least resistance. If a short or surge occurs that completely melts your RCA “ground”, it will try to travel through the next thing….a human body, a pet…anything creating a new path. You’ve now created a new path, maybe more preferable, that if water gets in, a piece of wire, a paper clip, a short from an internal component fail or solder fail could be unpredictable. Those interconnect areas are supposed to be very small voltages and completely unattractive to stray voltage. Accidentally leaving a system on and something overheats? I would also not purchase a “box” device to do something your system already did but then something failed or was repositioned to create an actual or apparent issue. Your ingenuity is great but in dealing with any voltages over 50V its best to do in a controlled environment or get solid PAID advice.

+1 nonoise. Agreed

@skipskip, if I followed your post correctly I believe you may not be realizing that nothing the OP has done has removed, replaced, or in any way defeated the normal AC safety ground connections of the equipment.

Regards,
-- Al

skipskip,  I am with almarg on this one, I don't see evidence the OP is defeating the safety AC cord ground.

In the US/Canada, unless the latest NEC/CEC has changed, it is acceptable to connect an isolated DC ground to chassis/safety ground, and technically if the voltages are >50V, it is a requirement you do, though I can't comment on the subtleties unless I delve back into that. In Europe, if my memory serves, on the DC isolated ground of an AC connected unit, you cannot connect the DC ground to the Earth/Safety ground for most applications (though for battery systems you do). Everything I do is isolated so I have not needed to delve deeply into this in a while, so if someone is more up on current regulatory requirements, please pipe up :-)

quanghuy147, as some have stated, maybe your solution is better, maybe not, but you believe it is, so lets make that assumption. Within any given piece of equipment, there are parasitic capacitors, potentially many of them, between PCBs, wires, and the chassis. The impact of those capacitors is how close the PCB/wires are to the chassis, and the frequency of both the signal (and noise sources). If you have some equipment that is poorly designed, then a connection from the DC ground to the chassis ground can eliminate some of those capacitors and make your system better.  This could be the case with sensitive analog circuits, but also systems with digital noise, switching power supplies, etc. 

Shorting the two grounds can also shunt common mode noise into the safety ground, instead of sending it out over your RCA cables.

If you are concerned with safety, but want to accomplish much of the same thing, instead of wiring directly from the one RCA to the AC safety ground, connect them with a capacitor. Ideally that would be what is called a Y-Rated safety capacitor. You can get them up to 1uF.  Typically these capacitors are small to prevent leakage current at 50/60Hz AC frequencies. At 120V, 1uF in series can pass 45mA, more than enough to kill. However, we are assuming you are keeping your AC cord safety grounds intact.

It’s safe.
Now, there are two complications:

1. as noted you could create a ground loop, but from your report of improved sound, you didn’t, so don;t worry about it.
2. Safety, and effectiveness, depend on how your component is grounded internally. The outside RCA connector is signal ground, for sure. But signal ground and chassis/safety ground may or may not be the same.

• they may be connected internally
• they may be independent internally
• there may be a switch (many of my designs had one to eliminate ground loops)
• They may be connected via a resistor, sometimes around 1-meg-ohm

So, while it won't injure you (its grounded after all), it might or might not provide an improvement.

G

Thank you everyone for your valuable inputs. I never thought that I could get this much help from audio community. 

So if I understand it correctly, what I am doing this is 99% safe. Besides, doing this can compromise the accuracy of the system.

However, I'm concerned about the 1% for my audio gears and safety of people around me. Also, I don't want to mess up with the accuracy of the system. Therefore, I am thinking about a DIY passive grounding box, which is a wooden box with different minerals inside. I think it does not take much time to turn what I am having now into a  DIY passive grounding box. 

Not to take sound quality into consideration, do you think that this solution is safer and less interferes with the accuracy of the system? 

I disagree that grounding options could reduce the accuracy of the system, **unless** they also created a noticeable hum.  no hum, no foul.
The key to grounding is to have ONE connection to ground - and everything else grounded to THAT.  Typically that one point is the preamp.
What I would do is

a) find out if your preamp connects signal and chassis grounds. Ideally float the signal.  Find out the same for your other components.
b) either  b.1) don;t ground any other components or b.2) ground them all to a single power strip/conditioner plugged into a single outlet.
never, ever plug some components into outlet #1 and others into outlet #2. That's the recipe for a ground loop.
Grounding chassis of components to actual earth (3rd plug) is always both safe and good at reducing radiated noise. The problem only occurs if the manufacturer connects chassis to signal grounds.
but I'll re-emphasis --- if it soudns better and has less noise, it almost cannot be creating a loop.
G

The statement that floating chassis from signal ground is always better is a simplistic view that is not always right. Ground hum is not the only form of noise (or distortion) that can be ground induced. That concept totally ignores signal induced noise on the ground that will not be evident when there is no signal and you are just listening to hum.

I am thinking about a DIY passive grounding box, which is a wooden box with different minerals inside. I think it does not take much time to turn what I am having now into a DIY passive grounding box.

Not to take sound quality into consideration, do you think that this solution is safer and less interferes with the accuracy of the system?

This appears to me to be perfectly safe.

As far as the possible sonic consequences are concerned, if the "minerals" are not conductive, and if there are no uninsulated ends of the ground wires making direct contact with each other, it seems to me that all you would be accomplishing is hanging a bunch of antennas off of the circuit grounds of the components.  Which in turn might pick up RFI and conduct it into the components.

If the "minerals" are conductive, or if uninsulated ends of some of the wires are in direct contact with each other, you will have established additional paths between the circuit grounds of some of the components.  Any sonic consequences that may result figure to be unpredictable, IMO.

FWIW, I personally would not consider such an experiment to be a worthwhile investment of time, but that's just me.

Good luck.  Regards,
-- Al