Tips
The Health of Your Safety Ground
The importance and impact of the home electrical system on a performance audio system have long been heralded as important, but not without a few misunderstandings as to why. Some of the fundamental misunderstandings stem from the focus put on delivering clean AC power, yet overlooking the critical role ground plays in achieving a low electrical noise floor. In this paper, I will discuss the three aspects of the grounding network that the consumer has some control over: the earth ground, your home's electrical safety ground, and the audio component's ground. I will also touch on the hot and neutral legs of the electrical path and their role in the purity of the safety ground. No specific product is identified or recommended — the principles discussed here are universal.
Part One: Why It Matters
The Three Tiers of the Grounding Network
As a homeowner, you have varying degrees of control over three aspects of the grounding network.
The first is the physical connection of your home's electrical system to earth ground. This is the foundation on which the entire electrical system runs — literally the connection of your home to the earth underneath. The companion article on grounding electrodes addresses the importance of determining how best to make that earth connection outside the house. This paper focuses on what happens inside the house.
The second is the safety ground network within your home's electrical system. This network ultimately ties to the earth, which serves as the stable reference potential for the entire system. Ideally, the safety ground conductor of every AC outlet in the residence should have zero impedance to earth ground. That is not achievable in practice — too much precision in the ground connection chain is required to perfectly achieve this throughout the house. For most electrical appliances and devices, ultra-low impedance to earth ground is not a requirement to function as intended. But for the components we count on as music lovers, a higher standard of grounding integrity is required. This paper is primarily about this second tier.
The third is the audio component's internal grounding scheme. This is the one tier you cannot control — but you can corrupt it. Everything discussed in this paper is ultimately about preventing that corruption.
From this point on, we will assume the safety aspects of the safety ground network in your home are sufficiently up to code and condition, and focus on how that network can impart noise into your audio components.
Component Reference Voltage (CRV) — The Concept That Ties Everything Together
To understand why the simple safety ground is so important, that electrical leg that carries no AC signal, it’s important to understand how our audio components rely on and can be disrupted by, this lonely and misunderstood connection.
I need to introduce a term here that you will not find in any electrical engineering textbook. That is deliberate. The engineering community has no single, agreed-upon term for what I am about to describe — in part because engineers cannot even agree on what the word "ground" means (more on that shortly). But as a consumer, you need a conceptual handle on this idea to understand the rest of this paper. So I am going to give you one.
Designers of audio components need to choose a circuit reference voltage — the voltage value around which every circuit in the component is designed to operate. This is often loosely referred to as a "Zero Volt (0 V) reference," as it is typically referenced to ground, which should measure as 0 V. In practice, that number is really an arbitrary starting value rather than an actual zero volts. It is a designed reference point. I will refer to this as the Component Reference Voltage, or CRV. This is my term, not any industry-standard one. I use it because it gives you, the reader, a way to think concretely about something that is otherwise invisible and abstract. I’m sure engineers will bristle at this idea, but most of us are not engineers and do not really understand how the components we love work on the inside.
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It is critical that all the individual circuits that make up an audio component operate from the same CRV. Since all of those circuits are connected to each other and interact as a functioning component, the CRV needs to remain constant throughout. When all the circuits operate with an equal and stable CRV, the component has the opportunity to function as designed. In the case of high-performance audio, that means sounding like the designer intended.
Noise that can disrupt and alter the CRV enters the component through two paths. The first is the safety ground conductor in the power cable — noise accumulated on the safety ground network reaches the component's chassis and couples into the internal ground plane. The second path is through every interconnect cable connecting one component to another. The ground conductor in an RCA cable, a digital coaxial cable, an XLR connection — all of these tie the internal ground references of two components together. If the DAC's ground reference is contaminated, that contamination travels directly down the interconnect's ground conductor into the preamp's signal ground. And the reverse is also true. Every component in the system is both a potential victim and a potential source of ground noise for every other component it is connected to.
Once noise reaches the internal ground plane through either path, it does not affect just one circuit. The circuits inside an audio component are not independent — they share a power supply and they share a ground reference. The output of one stage feeds the input of the next. When the ground reference shifts under one stage, that stage's output shifts with it. The shifted signal feeds the next stage, which amplifies it along with the music. That next stage's own ground reference may be shifted by a slightly different amount, because it sits on a different part of the ground plane. Each stage compounds the problem, and feedback loops within the circuit attempt to correct for errors that are themselves constantly changing. This is why the CRV needs to be stable — not just for any single circuit, but because instability cascades through the entire chain of circuits within the component.
Electronic engineers are keenly aware of this and strive to provide filtering in the component's power supply to protect and maintain the CRV regardless of the noise present in the outside world. It is a task that is much easier to discuss than to achieve.
Why "Ground" Means Different Things to Different Engineers — And Why That Matters to You
The word "ground" is one of the most overloaded terms in electrical engineering. To a power engineer, ground means the safety conductor and earth electrode. To a circuit designer, it means the zero-volt reference node on the schematic. To a PCB layout engineer, it means the copper return plane. To an EMC engineer, it means the chassis. Ralph Morrison devoted multiple editions of *Grounding and Shielding Techniques in Instrumentation* to the argument that this ambiguity actively causes engineering errors. Henry Ott's *Noise Reduction Techniques in Electronic Systems* — the standard EMC reference — devotes significant space to the same problem. They all know what ground is — they just define it based on what matters most to their discipline. A power engineer's ground clears faults. A circuit designer's ground establishes a voltage reference. A PCB engineer's ground manages return currents. None of them are wrong, but none of them are talking about the same thing. This is part of why a single consumer-friendly term like CRV is useful — the engineers themselves don't have one.
Regardless, it has a direct consequence for you as a consumer. The assumptions and techniques that different engineers apply to their designs to achieve a consistent CRV will vary — sometimes wildly — in their efficacy. Two engineers at two different companies may conceive of the relationship between chassis ground, signal ground, and safety ground in fundamentally different ways. Neither is necessarily wrong, but the interaction between their designs when you connect the components together with an interconnect cable can produce unpredictable results. What audiophiles often call "synergy" between components — or the lack of it — may in many cases be the accidental compatibility or incompatibility of grounding topologies that are invisible to the consumer.
What Actually Happens Inside the Component
The paper's central argument depends on understanding what happens when noise on the safety ground reaches the inside of an audio component.
The ground plane or ground bus inside an audio component is not a perfect conductor. It has finite resistance and, critically, finite inductance. When parasitic current from the safety ground enters through the chassis, it does not raise the entire internal ground reference equally. The current develops a voltage gradient across the ground plane's impedance. Different circuit stages — the input buffer, the gain stage, the output driver, the DAC's voltage reference — see slightly different "zero" potentials simultaneously. The CRV doesn't shift uniformly. It fractures. The component's circuits are no longer operating from a common reference.
This is the phenomenon that PCB engineers call ground bounce: rapid fluctuations in the reference voltage caused by current transients flowing through ground impedance. It is well-documented in the engineering literature, particularly for mixed-signal circuits where analog and digital sections share a ground plane.
The component's ability to reject this contamination is measured by a specification called Power Supply Rejection Ratio (PSRR). At DC and low frequencies, PSRR is typically excellent — 100 dB or more. A 1-volt change in the supply might produce only 50 nanovolts of error at the circuit's output. This is why 60 Hz hum from a modest ground loop is usually manageable — the circuit can largely suppress low-frequency contamination.
But PSRR degrades severely at higher frequencies. The engineering literature reports that rejection may fall to only 20–30 dB in the tens-to-hundreds of kilohertz range. At 45 dB of rejection — a real-world measurement for a precision audio op-amp at 100 kHz — high-frequency noise passes through to the signal path with relatively little attenuation.
This frequency dependence is the linchpin. The parasitic currents that accumulate on the safety ground network — EMI filter leakage, switching transient energy, high-frequency noise from dimmers, motors, and switching power supplies throughout the house — are predominantly high-frequency contaminants. They are precisely the noise that audio circuits are least equipped to reject. A circuit that effortlessly suppresses 60 Hz hum may be nearly transparent to 100 kHz noise on its ground reference.
How Contamination Reaches Your Audio System
Ground potential is a term you'll encounter in discussions about electrical systems, and I want to be specific about what it means here — because it is not the same thing as the CRV I described above. Ground potential refers to the actual voltage present on the safety ground conductor at any given point, measured relative to earth. In a perfect system, ground potential would be 0 volts everywhere — the safety ground conductor would sit at the same potential as the earth ground throughout your entire house. In practice, it never does. The safety ground conductor has impedance, and current flowing through that impedance creates voltage where there shouldn't be any. That voltage is ground potential contamination, and it is what ultimately enters your components and disrupts the CRV.
So ground potential is about the wiring — what's happening on the safety ground conductor out in the wall. CRV is about what's happening inside the component. Ground potential contamination is the disease. CRV disruption is the symptom.
The earth is what we define as the 0-volt reference — the baseline against which everything else in your electrical system is measured.
A common misconception is that the earth is a naturally low-resistance path for stray energy — that it effortlessly absorbs whatever noise your electrical system produces. It does not. The earth is actually a relatively poor conductor compared to copper wire. A typical grounding electrode presents 25 ohms or more of resistance to earth — which is the code maximum for a single rod, and barely adequate for safety, let alone audio. A hundred-foot run of copper wire? A fraction of an ohm. The earth's value is not that it is an easy path. Its value is that it is a massive, stable reference potential — and that when you do the work to establish a low-impedance connection to it, it becomes a highly effective sink for the parasitic currents and transient energy that would otherwise accumulate on your safety ground network.
This is a distinction worth understanding: the effectiveness of the earth ground depends almost entirely on the quality of your connection to it. Master electrician and NEC educator Mike Holt has been stressing this distinction for decades. He's demonstrated through testing that the earth path alone can't even carry enough fault current to trip a breaker. What he stresses equally is that for sensitive electronic systems, achieving a low-impedance connection to earth — in the range of 1 to 3 ohms — is both desirable and effective for reducing EMI, RFI, and static electricity. Think of it like a drain pipe. The reservoir that the pipe drains into may be enormous, but everything depends on how wide and clear the drain pipe is.
Resistance restrictions along the entire safety ground path choke the drain pipe leading to the grounding electrode, leaving parasitic energy with nowhere to go except elsewhere into the safety ground network, where it contaminates the CRV of your audio components. The companion article on grounding electrodes addresses how to make that pipe as wide and clear as possible.
But the safety ground network is not just a passive drain. It is a conductor, and conductors have impedance. All along the path the safety ground travels — from the grounding electrode at your service entrance through the breaker panel, through the wiring in your walls, to the receptacle in your listening room — constantly changing levels of interference get imparted onto it. Voltage, current, increased resistance from degraded connections, radio frequency interference, and other naturally occurring phenomena ride on that conductor. This imparted noise changes the electrical nature of the safety ground pathway, which in turn changes the nature of each component's common ground.
To put concrete numbers to this: a modern home might contain twenty or more devices, each with EMI filters whose Y-capacitors are designed to conduct current from the line and neutral to ground. This is by design — UL allows 0.5 to 3.5 milliamps of leakage current per device depending on classification. Twenty devices at 0.5 mA each puts 10 milliamps of aggregate high-frequency current on the safety ground network.
Here is where a basic electrical principle matters. Whenever current flows through a conductor that has resistance, it produces a voltage across that resistance. This is Ohm's Law: voltage equals current multiplied by resistance. The current on the safety ground is the mechanism; the voltage it creates is the actual noise that your components experience. If that 10 milliamps of current passes through even 0.5 ohms of connection resistance at a degraded receptacle or loose bonding point, it produces 5 millivolts of noise on the safety ground at that point. That 5 millivolts enters every component connected to that ground path and disrupts its CRV. At audio frequencies, that is well within the range where sensitive components can be affected — particularly given the PSRR limitations described above.
The chain looks like this: high-frequency parasitic currents accumulate on the safety ground → inadequate electrode impedance fails to drain them effectively → they develop voltage gradients at every connection point along the path → they enter your audio component through the power cord's ground conductor → they reach the chassis and couple into the internal ground plane → the circuit's PSRR is too weak at those frequencies to reject them → the CRV becomes noisy and spatially inconsistent → every signal process the component makes is compromised.
There is a very easy, birdseye view if noise is getting into your audio system. I typically measure the voltage between the neutral and ground legs on any system I work on. I can measure anywhere from a voltage too low for my multimeter (very rare) to almost 1V. Typical is 0.05V to 0.3V. That voltage gets directly connected to the common ground of any component that uses that line. And that is only one type of noise that can be imparted onto the safety ground.
Ground Loops, Common Ground, and the Component Ecosystem
Because stereo components are interconnected by many different electrical connections — all of which include ground in some form — noise that gets imparted onto the safety ground can cause any number of problems to manifest.
The chassis ground connection point inside each component is called the component's common ground. This is where the grounds of all the various operating circuits within the component converge into a single common ground for the component as a whole. Each component in your system is connected to the others not only through the safety ground network but also through analog, digital, communication, and power supply connections. All of these cable types also include a connection to common ground, which becomes a system common ground rather than a singular component common ground. You can see how this begins to look like the loop the term "ground loop" refers to — and it gets complicated quickly.
If any component in the stereo system has a different relationship to earth ground from the other components, many forms of noise will become present on the common ground of all components, and the CRV of each component will become compromised. How much each component is compromised and when it is compromised is unknown in all circumstances.
So what is a ground loop and why do we care? A ground loop is present when a group of AC-powered and interconnected devices have individually different electrical relationships to ground — in other words, unequal ground potentials. Since our stereo system is electrically connected together at multiple points on each component, the ground is by definition in a loop. When you hear the term ground loop, try replacing it in your head with: "my components have different ground potentials and that's not good."
How does unequal ground potential happen between components? The safety ground network connects to a component via the round connector on the power cable and the wall receptacle. Inside the component, the chassis is connected to the safety ground network — this is how the safety ground will protect you in the event of a short circuit within the component's circuitry. This is a code requirement, which is why ground lifting is not smart.
**A note on floating ground designs:** There is an exception to the most common audio circuit topology known as floating ground. The circuitry inside these components is electrically isolated from any portion of the component that you can touch. You can identify a floating ground component by its two-prong AC connector. One advantage of this design is that it is very immune to ground loops or noise on the safety ground — but not entirely. The downside is that it does not have direct access to the safety ground, so noise that exists inside the component cannot be dissipated into the low-impedance path to earth ground.
Inactive Noise and Active Noise — Two Different Problems
The simplest or most recognizable symptom of ground contamination is a 60 Hz hum, often called a ground loop. I call this **inactive noise** because it is not caused by or easily recognized as being influenced by the actual music signal. The hum from a ground loop can often be made to go away simply by using a cheater plug to bypass the safety ground on one of the components. This literally disconnects that component from the safety ground network to isolate it from the root cause, rendering the hum mute. Figuring out which component to disconnect can be done quickly, but finding the actual cause of the ground loop can be very time-consuming.
A simple illustration: disconnect a turntable ground wire and a hum will probably occur. Reconnecting the wire restores normal operation. But if there is a hum you did not deliberately create, disconnecting a component from the safety ground is not a good solution — the component is no longer grounded. On the safety side, this is a potentially significant concern. And on the performance side, you have not found the cause of the ground loop, and the inactive noise that manifests as hum is not the only byproduct.
There is a more insidious problem I call “active noise.” The audio system draws a constantly changing amount of current from the AC line as it reproduces music. That varying current draw constantly alters the nature and amplitude of noise imparted on the safety ground. The problem is that this increase in noise — and however the audio system reacts to it — coincides with the music playing. The noise is literally correlated with the music signal.
Active noise is extremely difficult to identify. You cannot point to a specific artifact and say "that is the noise." It manifests as a degradation of resolution, dynamics, and spatial clarity — what listeners often describe as a "veil" or a lack of "air." It is really only noticeable or can it only be appreciated in its absence?
How audio circuits react to this unstable reference is difficult to predict. A circuit that controls a volume display will probably function fine. But an audio circuit is a balancing act, operating with the dynamic nature of music. Circuits that generate large swings in current — like the output stage of an amplifier — will be more negatively affected by a changing ground reference than the volume display of a preamp. Sometimes the nature of the unstable ground relationship may have minimal effect on the sound but causes the server or DAC to lock up and become unresponsive. And if a component’s display is compromised, you may not notice that it looks a little less bright, but is it throwing off noise into the rest of the component as a byproduct of it not functioning well?
Why Balanced Connections Don't Solve This
A common assumption is that balanced (XLR) interconnections eliminate ground-related noise problems. This is only partially true, and it is worth understanding why.
Balanced interfaces reject noise that appears equally on both signal conductors — the voltage difference between chassis grounds is treated as common-mode noise and suppressed (Common Mode Rejection - CMR). This is real and well-documented. For the inter-component coupling path — the noise that travels between components through the interconnect cable — balanced connections provide a meaningful improvement over unbalanced (RCA) connections.
But balanced topology does not address what happens inside each component. The internal ground reference contamination — the CRV problem described above — exists regardless of whether the signal enters or leaves the component on a balanced or unbalanced interface. A fully balanced, differential circuit still operates relative to an internal ground reference. Its bias points, power supply rails, and voltage references all sit on the component's ground plane. If that ground plane is contaminated by parasitic currents from the safety ground, the circuit's operating point shifts.
The circuit's ability to reject common-mode noise also degrades with frequency — just as PSRR does. At higher frequencies where ground contamination is worst, a balanced interface may offer only marginally better rejection than a well-implemented unbalanced connection.
This matters because every recommendation in this paper — low-impedance earth ground, dedicated lines, same-phase breaker connections, equal-potential distribution — applies to balanced systems just as much as to unbalanced ones. The contamination manifests internally rather than at the interconnect, but the CRV degradation is topology-independent.
Neutral-Ground Bond Errors — A Common and Impactful Source of Contamination
One source of safety ground contamination that is worth specific mention: improper neutral-ground bonds downstream of the main service entrance. The National Electrical Code requires the neutral-to-ground bond only at the main panel. A bootleg ground — where neutral is bonded to ground at a receptacle — or an improper neutral-ground bond at a subpanel puts return current directly on the equipment grounding conductor. This is precisely the type of contamination this paper has been describing: current on the safety ground that should not be there, creating voltage gradients that compromise the CRV of every component connected to it.
This is one of the most common residential wiring errors and one of the most impactful for audio systems. If you have an electrician evaluate your grounding, checking for improper neutral-ground bonds throughout the house is time well spent.
Part Two: What To Do About It
Aside from what noise the stereo system can impart upon itself, something I hear audiophiles talk about frequently is wanting to isolate their stereo system from all the electrically noisy products in their home. Yes, these products share the same safety ground as your stereo system, so it is natural to want to separate them. But we cannot disconnect the stereo system from the safety ground. What we can do is minimize the noise on that conductor and optimize its role.
1. Ensure a Low-Impedance Path to Earth Ground
When the connection to earth ground is low-impedance, parasitic currents on the safety ground — all that accumulated leakage from every device in your house — can dissipate through that path before they develop the voltage gradients that raise ground potential at your receptacles and ultimately disrupt the CRV inside your audio components. Lower impedance means less voltage developed along the way. This is the drain-and-pipe principle I described earlier: the earth is a vast and stable reference, but everything depends on how wide and clear the pipe is.
Have an electrician check the grounding electrode resistance to earth to determine its effectiveness. Ensure the grounding electrode achieves the code maximum of 25 ohms or less — too high a resistance here is unsafe as well as being a cloggy pipe drain. But don't stop at code minimum. Strive to get that value as low as possible. Under 5 ohms is the goal, and lower is better. Low resistance is tied to how efficiently the electrode connects to the earth, so surface area and soil conditions are factors. Achieving a very low resistance connection may require installing a new corrosion-free ground rod, extending the electrode length beyond the 8-foot code minimum, or installing multiple electrodes. The companion article on grounding electrodes covers this topic in detail.
2. Install a Dedicated AC Line with MC Cable
Installing a dedicated AC line from the service entrance to the sound room is a common approach to improving the sound of an audio system. A dedicated line means no other receptacles are attached — only the stereo system uses it. Specifying at least 20-amp capacity means a larger and lower-resistance safety ground conductor.
However, depending on the design and configuration of the wiring, the hot and neutral conductors can impart significant amounts of noise onto the ground conductor. When your house was built, it was almost certainly wired with Romex. Romex is that flattish looking cable you see stapled to the 2x4’s in your walls. In a Romex cable, the hot and neutral wires run parallel to each other and are separated in the middle by a bare copper ground wire. In a straight run, the symmetry of the three conductors is such that whatever noise couples from hot to ground roughly matches what couples from neutral to ground, so there's some degree of cancellation. If that symmetrical parallel geometry deviates, say around one of the many corners the cable will travel within the house, the asymmetry of the wire’s proximity reduces some important natural cancellation the cable may have provided. A 120V 60 Hz fundamental doesn't couple much through a few inches of conductor proximity change. But the harmonic content and high-frequency switching noise riding on that hot conductor couples more readily, and every bend creates an opportunity for that noise to get onto the ground wire. Luckily, there is a different AC cable type called MC that is an excellent choice for an audio system’s dedicated run. Specifically, we are looking at a steel jacketed MC cable. This specific type of MC cable houses the hot, neutral, and ground conductors, mildly twisted together, inside an interlocked steel armor. There doesn’t seem to be an industry standard about how many twists per foot MC cables have, but my experience is that it’s roughly 3-4 twists per foot within the armor, providing some degree of cancellation of induced noise, but maybe more importantly, greater proximity stability between the three conductors. It’s not as calculated as the symmetrical “twisted pair” cable concept you read about, but it’s far superior to Romex. But the primary benefit of MC cable is probably the steel armor itself — it provides electrostatic and electromagnetic shielding that the PVC jacket of standard Romex cannot. There is an aluminum jacketed MC cable as well, but its electromagnetic shielding is dramatically less effective at the frequencies that matter most for audio — the 60 Hz harmonics and switching noise riding on the AC line. Note, the NEC does have specific requirements on how the steel jacketed MC cable is terminated at the receptacle junction box, but your electrician is well aware of this and will have no problem making the correct termination. An MC cable with 10-gauge wire (which exceeds the code requirement for a 20-amp line) would be referred to as 10-2 MC Cable. An 8-gauge wire would be 8-2 MC Cable. The first number is the wire gauge and the second is the number of AC-carrying conductors. Check to make sure that with any MC cable you consider, the ground wire is the same gauge as the hot and neutral wires.
As with anything, there will be varying degrees of quality between MC cable brands. Since one of the reasons we are specifying this cable type is to prevent noise from being imparted on the ground conductor, precision and quality play a role here. Additionally, not all MC cable has all three conductors individually insulated. With lesser priced product, the ground wire is often left uninsulated. All three conductors being insulated has much more uniform proximity between the conductors, will maintain more consistent position in the steel armor when the cable is bent around a corner, and implies a higher quality product because it costs more money to insulate all three conductors. I’m going to break my rule this once and recommend a specific product. I have found that the company called Atkore makes a product called MC Glide Tuff in a 10-2 configuration, where all three conductors are insulated. Make sure your electrician specifies the 10-2 MC Glide Tuff product with a 10-gauge ground wire. Atkore offers so many different 10-2 MC Tuff configurations (primarily color-coded) that he could accidentally order the smaller 12-gauge configuration. My clients have had excellent results with these products, and I have found them to be of very high quality.
3. Connect All Audio Circuits to the Same Phase
If more than one dedicated line is installed, ensure that all lines are connected to the same phase in the breaker box. Our U.S. electrical system is a 240V split-phase system — 240 volts comes into the home from a center-tapped transformer and is split into two 120-volt legs that are 180 degrees out of phase with each other. The circuit breakers in the panel typically alternate between the two legs from top to bottom.
When audio components are powered from different phases, the different phase relationship creates different leakage current patterns on the safety ground and can introduce 60 Hz or 120 Hz voltage differentials between components' chassis. Since we are connecting together precise and sensitive components with a common ground, we want all of them powered by the same phase. This applies whether your interconnections are balanced or unbalanced — the inter-component coupling is worse with unbalanced connections, but the internal ground reference contamination from opposite-phase leakage currents affects all components regardless of interface topology.
4. Use Hospital-Grade Receptacles
The AC receptacle where the dedicated line terminates will impact the transfer of voltage and current, as well as the impedance of the safety ground conductor between the dedicated line and the power cable. A loose-fitting or aged receptacle will be very inefficient when a large current draw is required by an amplifier. Some external power supplies for preamps, DACs, and CD players also require extremely fast current delivery. If the receptacle is loose or the contact metal is fatigued, it will negatively impact the immediate delivery of current and voltage.
Hospital-grade receptacles are tested to stricter standards: higher ground contact retention force, additional tests for assembly integrity, impact resistance, and abrupt plug removal. The real advantage over residential-grade outlets is longevity and consistency of contact pressure over time. A quality specification-grade or hospital-grade receptacle ensures tight, secure connections that maintain their integrity for years. The Hubbell brand is common and widely available at hardware stores.
Aftermarket “audiophile grade” receptacles.
I have found that the attributes of hospital-grade receptacles can improve the performance of an audio system. I have also found that the attributes of many of the receptacles sold under the audiophile-grade category can provide even greater benefits. Sometimes with startling results. Different materials, different build styles, certainly different mechanical energy control techniques, all seem to alter the nature of how and what is delivered to the audio components. I say how and what because the receptacle doesn't just pass current — it influences all three conductors, and not always in obvious ways. A number of companies have addressed some of the more deleterious aspects of that interface, each with different approaches, many of which can be seemingly quite expensive. But if we are going to the lengths of exploring how to reduce the resistance of the safety ground all the way back to the grounding electrode, making sure all those wire connections are screwed down tight or exothermally welded in place, it stands to reason we would explore how to improve the weakest electrical link in the chain; the AC plug and receptacle connection.
5. Use Equal-Length Power Cables and Star-Grounded Distribution
Remember that all the components' common grounds are connected by the safety ground network as well as the ground pathways in the various connections that form the audio system. We are trying to avoid noise of any kind being present on the safety ground conductor. But we put it there — in the pursuit of performance, all the time, pretty much without fail. It is not really the consumer's fault, because as an industry, there is not a lot of buy-in for a best electrical practices approach to power cabling. This is a shame because it is very simple.
Whether you believe power cables have an impact on the sound or not, it is established science that when two or more grounded and interconnected components have unequal potentials — meaning different electrical relationships to the safety ground network — current will be present on the safety ground conductor, which is then present on the common ground. That is what most people refer to as a ground loop. "But I don't have a hum, so I don't have a ground loop!" As I have noted throughout this paper, anything other than a stable CRV for these circuits will cause them to behave outside their intended envelope. A ground loop without audible hum is still a ground loop.
The solution is straightforward. Envision the power cable you plug into each component as nothing more than an extension of its common ground. If we want that relationship to be the same for all components, then the power cables all need to be the same length and of the same design. Done.
Next, how do we get all those power cables plugged in? The simplest way is a power strip of some kind, where all the component cables plug into the strip and one cable goes to the receptacle. That is fine, but there is a critical requirement: the power strip absolutely needs to be a star-grounded device. Star grounding is a configuration where each device has the same potential and is tied to one point. A star-grounded power strip has an equal length and type of wire running from the ground connection of each receptacle to a single point that connects to the safety ground network.
Simply using the same length and design of power cable for each component, feeding into a star-grounded power distribution device, will create a much quieter environment for the safety ground — and in turn, a more stable CRV for each circuit in the entire audio system.
The Foundation
In terms of high-end audio prices, the total cost to have an electrician come in to evaluate or install an earth ground and run a dedicated electrical line to the listening room is pretty minimal. People pay far, far more for a single power cable. If someone came to me for advice on where to start building a high-end music system, I would recommend they do everything described above before buying their first piece of equipment. This is the most cost-effective investment you can make to build or improve an audio system.
What I have described in this paper are the foundational concepts behind the safety ground network and its relationship to your audio system. I have deliberately left out topics like power conditioners, cable design specifics, materials choices, circuit breaker designs, enhanced earth grounding techniques, isolation transformers, and mechanical isolation. I have experienced meaningful and often dramatic results using advanced products addressing all of these areas. For example, the design of a power cable can absolutely influence the nature of the safety ground conductor — if I am asked whether I think power cables can result in improved performance of an audio system, I would say absolutely yes, if for no other reason than their effect on ground noise.
In the simplest form: the electrical system should provide a low and uniform impedance path to earth ground for each component connected in the audio system. A low-impedance earth-to-electrode relationship. A dedicated, shielded AC line to the stereo system designed to prevent noise on the safety ground conductor. Low-impedance, secure connections for the system to interface with the AC line. Power cables of the same design and length, gathered in a star-grounded device that maintains equal potential for all components. These steps do not have to be expensive. You can use generic power cables — just follow the design and length guidelines. Use a generic star-grounded power strip with no enhanced filtering or conditioning. Just make sure the receptacles are tight-fitting and of hospital-grade quality.
These principles will help you make well-reasoned decisions about how to advance the performance of your system when you choose to do so — because yes, those more advanced and expensive cables can and do make a very significant improvement. They are just a lot more effective when these foundational concepts are achieved first.