Technical Articles
Distributed Power Conditioning is Shunyata Research’s innovative concept in solving power-line related noise using a multi-point approach targeting noise at its various sources.
It is well-known that vibration can adversely affect sound quality in a sound system. The DFSS (Dark Field Suspension System) Cable Isolation System measurably reduces cable vibration from the floor, thereby improving the listening experience. Here is a graphic showing two identical cables, one without cable suspension (yellow), and one with the DFSS cable suspension system (green). An accellerometer attached to each cable shows vibration from the floor.
DTCD® Technology
The Shunyata Research DTCD® Analyzer is the first and only power analyzer designed specifically to measure the differences between AC power cables, wires and connections.
We interrupt our regularly scheduled analog programming for this important message: Shunyata Research’s proprietary DTCD® Analyzer finally proves that power cords, power conditioners, circuit breakers, even fuses measure differently, and that perhaps these measured differences are what audio enthusiasts hear when they swap out these elements in their systems.
Michael Fremer, Stereophile, USA
For years, the debate has raged on-line and off regarding the perceived value of after-market power cords within professional and consumer audio-video systems. Though there are many sound and visual professionals who report experiencing dramatic differences when replacing stock power cords, there are still skeptics who point to a lack of measurements as proof that no real difference can exist.
Shunyata Research scientist, Caelin Gabriel, has put an end to the debate by revealing not only one — but three dramatic measured differences between stock power cords and an inexpensive audio-grade power cord.
DTCD® (Dynamic Transient Current Delivery) Analyzer
DTCD® is a method of current analysis that measures instantaneous current delivery in the context of a pulsed current draw. In layman’s terms, it is a way of measuring current performance into typical electronic component power supplies.
The DTCD® Analyzer allows the measurement of pulsed transient current through a variety of AC power products, including power cords. The measurements represent three critical performance criteria:
- The quantity of instantaneous current available through a specified power device or circuit. Measured in amperes.
- The amount of voltage drop across the device during the conduction period.
DTCD® Current Measurement: This measurement depicts the difference in available impulse current between Shunyata’s VENOM-3 power cord ($99 retail) and a standard black component power cord. Note the enormous difference in the quantity of current available compared to the stock power cord. The stock power cord delivers only 47% of available current compared to 84% with a VENOM-3 power cord. By any standard of measure, this is statistically significant.
Voltage Drop Comparison: The voltage drop depicted for the stock power cord was so profound that several models were tested to validate the standardized measurement. A 15 volt drop in voltage during the conduction period compared to only a 5 volt drop with a Shunyata VENOM-3 power cord represents a night to day objective difference. This magnitude of difference is certainly significant in a high performance entertainment system.
The Shunyata Research DTCD® Analyzer is the first and only power analyzer designed specifically to measure the differences between AC power cables, wires and connections. Previously published DTCD® measurements revealed dramatic peak-current and voltage delivery advantages when substituting a quality 12-gauge power cord (Shunyata’s VENOM-3) for any stock power cord.
Wire Gauge Comparison: This graph plots the differences between power cables of different wire gauge size. These measurements were generated by the DTCD® Analyzer from actual stock power cords. Notice the progressive improvement in instantaneous power delivery as the wire gauge is increased from 18 to 16 to 14 gauge*. *(Wire gauge is inversely proportional to the number — 18 is smallest and 14 is largest)
Connector Comparison: DTCD® measurements also reveal differences between connectors and connection methods. The first cable labeled “Molded” is a standard cable with crimped and molded connectors. The second cable is identical except the molded connectors have been cut off and replaced with high quality Hubbell connectors. Notice that the DTCD® Analyzer clearly shows a significant increase in current delivery. (NOTE: Both cables measure identically using conventional volt / current meters)
Geometry Comparison: The DTCD® Analyzer is the only device that measurably demonstrates the difference between cable geometries. The VENOM-3 and Black Mamba CX are both 12-gauge power cables. The VENOM-3 cable uses a simple 3-wire twisted geometry while the Black Mamba CX uses 140 conductors in a complex Helix geometry. Notice the Black Mamba’s dramatic improvement in current response! Then, consider that this difference in current response is repeated 120 times per second in a typical A/V power supply.
A note to engineers: All the graphs were generated in Excel for simplicity and readability. The graphs were generated directly from the data captured by the data storage oscilloscope. The data has not been modified or enhanced in any way.
Before examining methods of setting up an ideal electrical delivery system for recording, music and sound reproduction, it helps to understand why electrical conditions have a profound impact on sound.
The Importance Of Electrical Delivery To Recording And Sound Systems
Too often, the AC system is misunderstood in its relationship to the performance of recording or playback systems. This can lead to the misapplication or over-application of AC treatments — or the extreme of ignoring the power-delivery system as inconsequential altogether. In both cases a corruption of the system’s most fundamental signal will be the result.
The Source of Sound
When referring to a playback or recording system’s “source” most people will make a reference to the actual media, whether it is voice, instrument, a record, CD or tape. However, from the perspective of electronics systems there is a far more fundamental, underlying “source” than the media being transported through a recording or replay system.
The actual source of what we hear in any recording or playback system is the power as supplied from the wall after being rectified by the power supply into a relatively stable DC source. It is this DC power source that is the fundamental energy source that makes sound possible. For example, in an amplifier it is the DC source current (modulated by the signal source) that drives the coils in a speaker. If the power source is unstable or contaminated then the output will be as well regardless of the information in the signal source. If the AC power varies or if there’s some anomaly in the power source it will show up clearly in the audible range. The assumption that power supplies provide perfect noise-free DC voltage that does not vary under load, is fanciful at best, complete fiction at worst. There is no such thing as a perfect power supply capable of filtering, blocking or managing multiple forms of high-frequency EMI and RFI interference produced by electronics systems. In the simplest terms, alternating current represents the foundation of reproduced sound in recording, sound and music systems.
A Historical Brief
For years, the predominant approach to an AC system was to install a large, usually heavy, multi-outlet box with some type of massive low-pass filter ie: transformer, choke or coil. These were designed with the view that AC delivery is a simple, low-frequency event requiring protection only from external, grid-related sources of high-frequency noise, line spikes and voltage surges. These boxes were viewed as virtual brick walls, keeping out all grid-borne noise, surges or spikes that posed challenges to the performance and safety of electronic systems. However, two principle issue were overlooked. The primary issue with the low-pass filter or regenerator approach lies in their inability to deliver instantaneous peak current impulses to full-wave bridge-rectifier or digital switching power supplies in the time in which they would normally receive them from the wall. The second and equally important consideration is the fact that these one-way noise rejecting designs also block noise generated by the components themselves, reflecting that noise back to the other components in the system.
Upon Close Inspection
Electronic power supplies don’t pull current in a linear fashion like a light bulb, fan or simple motor would. The full-wave bridge rectifiers and digital switching supplies in electronics draw hard on the AC line, pulling instantaneous bursts of current off the highest and lowest peaks of the sine-wave. This happens within milliseconds in order to fill power supplies storage capacitors. Both full wave bridge rectifiers and digital switching supplies create a significant amount of noise during this process that extends in frequency to the 50th harmonic of the line frequency. What this means, is that from the perspective of power-supply, AC transmission is a near-field, high-frequency occurrence not a low frequency 50-60Hz event.
With this basic understanding of the role AC plays in sound and the high frequency noise electronics systems create, two key elements emerge that are paramount in building an ideal power-system: Dynamic Transient Current Delivery™ (DTCD®) and Component to Component Interference™ (CCI™).
DTCD® — Dynamic Transient Current Delivery™
Maximizing the unimpeded instantaneous and continuous flow of current to electronics is critical to recording and playback systems performance. Recording and sound playback electronics are designed to perform optimally through an unrestricted interface with current. This is as true for source electronics as it is for amplification. Placing anything in front of an electronics system that restricts, impedes or slows the DTCD® of AC power will degrade the ultimate performance of the system. This is why most electronics manufacturers discourage the use of power conditioners that interfere with instantaneous current flow. Starting at the AC panel there are simple methods and measures anyone can implement to improve their entertainment system’s instantaneous access to its power source without compromising protection or performance.
CCI™ — Component to Component Interference™
A primary concern when building an electrical delivery system for recording or sound should be the isolation of individual components from the high-intensity fields of EMI and RFI noise that saturate the space surrounding electronics systems.
The power supplies of sound and recording electronics are by nature interconnected and in close proximity to one-another. All components in these systems have a unique electrical footprint and out-put noise from their digital switching or bridge rectifiers within the power supplies. Power supplies generate significant EMI primarily from the switching rectifiers. Digital equipment also generates high frequency RFI.
Both RFI and EMI may be transmitted from one component to another in several ways. The first is through conduction via the power cord connections and through interconnects. The second is through inductive coupling via power cords and other electronics connections.
Not only do power supplies emit a back-wave of noise energy through the ground system and power cords, their digital switching supplies or rectifiers radiate intense fields of gigahertz EMI. This affects all electronics and cabling within their immediate environment.
By far the most effective means of minimizing the impact of this noise lies in treatment of the initial outward points of electrical interface for each component — the power cord and the system’s main distribution points, the AC distribution buss/power conditioners.
A properly designed power cord can act as the first line of defense by isolating the power-supply port and IEC area from the radiated energy that surrounds electronics. They should also act as low-impedance path for the back-wave of power supply noise to reach an exit path from the system. Power cables that have low measurable impedance, resistance and reactance are preferable because they can provide a neutral connection for reactive power supply signatures and allow the cleanest exit path for ground noise to be dissipated/filtered at the connection with the distributor.
The primary role of the power distributor — outside of providing optimal DTCD® and simple protections from spikes and over-voltage — should be to provide a passive exit path for system-generated noise. The best distributors will offer individual component isolation so that the ground noise flowing out from one component does not affect other components plugged into the same AC distributor. It may sound simple and that is the goal. Power distribution should be an uncomplicated delivery path for the instantaneous AC impulses that allow electronics to perform at peak efficiency.
Contrary to popular theory, grid related or external noise generated outside of a systems immediate environment is vastly over-rated as a threat to system performance. Most if not all quality electronics have built in power supply elements that are more than capable of filtering or re-directing incoming noise — which pales in its effect to the massive amount of noise that is generated within the system. Given that the most sensitive electrical elements lie within recording and playback systems, this is a good place to start in building an ideal power-supply chain; one designed to deliver maximum current and minimum AC related distortions.
The fundamental design of interconnects, power cords and power distribution can radically affect EMI and RFI contamination — which in turn will dramatically affect the resolution and detail in recorded or reproduced sound.
Keeping It Simple
If we accept that electronic power supply’s interface with current is a high-frequency, dynamic (short-term) event then it becomes clear that the ideal signal path for current should be direct, with minimum added complexity. Providing simple, unobstructed, low-impedance pathways for current using solid connections and high quality materials will yield by far the most consistent and desirable results. The closer the signal navigates toward electronics the more critical these elements become. Conversely the more complex, obstructed the path, or the more reactive elements that are used between the panel and a system of electronics, the more compromised and unpredictable the results will be. Keep in mind that reducing perceived noise is only valuable if it can be done without restricting or impeding DTCD®. Some may value a reduction of perceived noise to a degree that makes losses in timing, immediacy and dynamics tolerable but when compared to sound that is uncompromised with regards to dynamic contentandhas noise isolation, the choice is clear.
The power-system components that are easiest to control, such as power breakers, grounding, dedicated lines, outlets, power distributors and power cords should perform two simple functions. Each part of the AC chain should be treated or selected to provide Dynamic Transient Current Delivery (DTCD®) to the electronics or when close to the system itself, to isolate the effects of radiated or conducted.
There are no bells and whistles that describe Shunyata designed products. No buzz words, LED’s or velvet-lined boxes. Shunyata Research products are an accumulation of deep engineering and the finest parts, materials and metal treatments in the industry.
All Shunyata products are meticulously tested, designed and manufactured to minimize the in-line AC resistance that measurably detracts from the performance of professional and consumer audio-visual electronics. Shunyata designs also minimize the effects of system and grid generated high-frequency noise. This combination of attributes allows electronics systems to perform free of the constraints normally associated with stock delivery systems or a mixed accumulation of widely differing approaches and designs.
The following is a complete guide to better understand the links in the AC system, why they are of critical importance and how they should be chosen. These recommendations are based on Shunyata’s own measurements, engineering principles and years of experience building electrical systems for the world’s finest musicians, recording engineers, electronics manufacturers and customers.
Why the Power Cord is Important
A properly designed high-performance power cord should function as a noise-isolated, low resistance interface between a power source and the components power supply. It should fundamentally do two things: provide a highly conductive, linear pathway for DTCD® and minimize induced and radiated electromagnetic interference (EMI). Seen in this manner, their function takes on a more prominent and understandable role. They represent the initial outward electrical interface for each component in the system. If left unaddressed, this initial interface may act as antenna for radiated and ground-borne noise while the conductors, dielectrics, contacts and connection points may imped DTCD®.
Power cords do not represent the last few feet of an AC grid leading to a component; they are the first few feet from the perspective of the component’s power supply. The further a potential noise source is from a component, the less impact it will have upon the circuitry within the component. In essence, the component represents the beginning of an electrical interface, not the end.
Given that a power cord is an outward extension of the primary winding within a power supply, literally everything about a power cord’s construction will impact performance. Every parameter of a power cords design should be purpose built to optimize the AC interface. It should be constructed from top quality connectors, high quality copper conductors and RFI/EMI shielding or a noise canceling wire geometry. Finally, an exceptional power cord should be designed to have a neutral reactive signature, meaning minimal capacitive and inductive properties so that it will perform compatibly and consistently across a broad range of electronics.
Power Cords as a System
Power cords should not be viewed as individual standalone items but rather as an integrated system with the goal of optimized DTCD® and minimal RFI/EMI distortions. Power cords interact with one another when they are connected to the same power line circuit (same outlet). This means that when one model or one type of power cord is tested it becomes inextricably linked both electrically and in terms of its performance signatures with other cords in the system. This is one of several reasons why opinions differ when trying a single model of power cord mixed with others of varying designs. Most will find however that when evaluating models from a single maker they will have a uniform performance signature that is consistent across systems. For these reasons, when evaluating power cords attempt get enough of the model you want to try so that you can replace all the cables in the system. It is impossible to gain a good understanding of any single power cord in a mixed system without alternately evaluating it as part of a closed single manufacturer system.
High-End Alternatives
There are so many makes and models of after-market power cords available that it can be a daunting process to choose models that may be worth the time to experiment with. The best method to select likely candidates is simple: do a little homework. Choose designs that have explainable technology, a track record of legitimate commercial success and that appear to be purpose built and well made. The better power cords do not change the fundamental sound from recording or playback systems. They get out of the way and allow the component and system to perform as it was intended to.
The only obvious differences when replacing stock cords with better should be a noticeably reduced noise level and a rather striking improvement in micro-dynamics — audible but subtle shifts in sound pressure and immediacy. Avoid designs that alter frequency balance or push detail forward or back, or those that tilt the delicate spectral balance in sound too far in one or another direction. Commercial after-market power cords do not have to cost thousands of dollars to perform well. Like anything else, time spent gaining experience and exposure is the best teacher in determining the perfect fit between value and performance.
Power Cords and Burn-In
A new power cord needs to “burn-in” to perform optimally. A new power cord will sound relatively blurry and indistinct when first applied to the system. It takes about five days of continuous current draw for a power cord to burn-in. Using an adapter and attaching the power cord to a fan or light is the best method to burn them in without having to listen through the initial annealing process.
Power Distribution and Power Conditioners
Since most homes and studios have only have a single duplex AC outlet along a wall and most A/V systems have more than two components, it becomes a requirement to have some sort of power distribution. In its simplest form this would be a common power strip. In many cases a power distributor will also include current and surge protection.
The majority of multi-outlet power distributors or active conditioners act as an entertainment systems’ common interface and contact point for distributed power. Due to the convergence of multiple electronics at this single junction, the crucial role of the power distributor or conditioner becomes clear.
Special attention should be paid to literally every aspect of a distributor’s construction with the principles of DTCD® and CCI™ in mind. An ideal distributor will use of heavy gauge wiring, top quality outlets, connections and termination points that preserve contact integrity and DTCD®. Another ideal distributor attribute would be an ability to filter not only the small amount of noise from the power grid but more importantly a means to filter the back-wave of noise generated and propagating from the system itself.
Taking a simple view, a power distributor should act as nothing more than an extension of the power cord in terms of current delivery. The power cords help isolate components from radiated CCI™ that surrounds electronics. The power distributor should act as a zero point for power line conducted rectifier noise and digital hash. The power cord and power distributor work symbiotically to isolate the two most damaging forms of CCI™ while maintaining the continuity of instantaneous current. Obviously, a power distributor should also have surge protection to protect from catastrophic spikes — though these elements are more ideally placed at the electrical panel — more about that in the electrical panel section.
High-End Alternatives
The key to choosing the ideal power-distributor system lies within the concept of keeping things simple and uncomplicated. For the best performance in the context of recording or reproducing sound, choosing a distributor that optimizes DTCD® is preferable over a design that emphasizes external noise isolation at the expense of DTCD®. Designs that use transformers, coils and baluns are inductive and by their nature impede instantaneous current delivery. This may cause a loss of phase and time coherence (PraT), losses in perceived voice and instrument weight and overall compression of dynamics.
If the designers of top performing recording and playback electronics wanted another inductor in line with the primary coil of their transformer, they would have put it there. If they wanted another type of reactive device, it would already be within the design. Manufacturers of today’s finest sound and recording components designed their power supplies to interface with the original AC wave-form, not one that has been processed, re-directed or impeded.
Outlets
Similar to power distributors, an outlet at the wall is often a critical common contact, or current interface point for multiple electronics in a system. Outlets represent another open contact that can increase line impedance and create losses in connectivity and conductance that affect performance. Even the tightening and termination of the wire behind the outlet to its hot, neutral and ground terminals is of significance. Keep in mind that multiple, or even a single loose connection point can severely impair the performance expected from any top tier system.
Most outlets that are installed into homes are the lowest cost models available. Low cost outlets retail for about 50 cents while a high quality commercial grade unit will go for more than $20. Obviously, there is no incentive for a residential developer to install quality outlets. The superior contacts are invisible to the user. For the audiophile this is a low cost opportunity to improve power system performance. Replace the outlet powering the audio system with a good heavy-duty commercial grade outlet. If your power circuit has multiple outlets you will need to replace all the outlets with quality units even if the audio system is not connected to the other outlets on the circuit — Leviton and Hubbell both make suitable products.
Isolated Ground Outlets?
An “isolated ground outlet” is a term that comes from commercial buildings’ power systems. Commercial buildings often require the use of metal conduit to contain the power lines within a building. Without getting too technical, the term isolated outlet has no relevance unless your AC power circuit is contained within metal conduit and has a metal outlet box. It is NOT necessary to use an isolated ground outlet in a home environment and it has no performance advantages whatsoever.
High-Performance Alternatives
Outside of top quality commercial outlets such as Spec grade Leviton and Hubbell, there are now many brands of specialty “Audio-Grade” outlets on the market, some costing hundreds of dollars or more. These outlets often have special contact plating, polished surfaces, unique material and metal treatments. What’s notable about all of them is that they will invariably sound different from one another and subjective preferences will often play a role in choosing one over another. Just as with after-market power cords, more expensive does not necessarily mean better no matter how precious the metals are.
The critical elements in selecting an outlet for applications related to sound and recording are covering the basics of conductivity and a secure connection. This means that there should be high quality conductive base metals used for the contact points and that there are broad heavy gauge contact surface areas internally. Contact points for wire should also have generous space for 10 gauge wire termination and broad brass or copper base metal surface areas. Outlets with wide internal chassis are preferable for their better air cooling properties and reduced heat at contact points.
Silver, gold and nickel plating may seem like a plus but “premium metal plates” often have obvious or overt sound characteristics — one warm and rich while others are sharp, cool and lean. Contact platings do not enhance DTCD® nor do they provide measurable noise reduction. Most often these simply act as tone-shifting elements rather than an enhancement to connectivity. As is often true in high-performance markets where price extremes exist — more often the best value and performance solutions lie in the more reasonable price ranges and with the more explainable science.
Dedicated and Isolated Power Lines
For those that are able to have dedicated lines installed, these are perhaps the greatest gift you can give to the DTCD® performance of a recording or playback system. There is a lot of confusion surrounding dedicated lines and isolated outlets among audiophiles. Let’s start with the definition of a dedicated line. Most power circuits in a home are daisy chained with multiple outlets on a single circuit. When you “flip” the circuit breaker to the outlet powering your audio system go check the other outlets in the room and adjacent rooms. You will find that several other outlets are being powered by a single circuit breaker. A “dedicated line” is a term used to describe a circuit breaker that is dedicated to a single outlet. It is not connected to any other electrical outlet or switch. The in-wall wires are all dedicated to that single outlet and cannot be shared with any of switch or outlet.
Why They Matter
In layman’s terms, any “less crowded” circuit will allow the electronics on that circuit better access to the instantaneous current impulses that are inextricably linked to the system’s signal “output”. This is especially true for amplifiers, whose full-wave bridge rectifiers pull extremely “hard” on the AC line. In fact, taking almost any amplifier off of a shared line (with other electronics) and placing it on its own dedicated line will render immediate and unmistakable benefits (largely dynamics) — in sound, proving how short-duration current-transient sensitive electronics really are.
Whenever possible, installing separate lines should be a primary consideration when building an electrical delivery system for studio, home or recording. Adding two or three dedicated lines is ideal — allowing for the separation of high-current and low-current electronics. In terms of overall performance, isolating high current electronics such as amplifiers, projectors, recording panels or powered speakers from source or low current electronics is far more beneficial than the separation of analog from digital. The availability of separate circuits also confers many options in terms of multi-outlet distribution units. Amps could connect directly to outlets for example while line and source components use some type of non-peak current limiting distributor.
Installing an individual dedicated circuit, or better two dedicated lines, will dramatically improve total available current capacity and associated system DTCD® . This does not discount the other elements in an AC system chain. To the contrary, adding a dedicated lines only enhances and punctuates improvement in electrical efficiency or reductions in CCI™ elsewhere. It’s the open “system” of AC that matters most. All other parts should serve the same open-channel theme.
Avoiding Ground Loops
With the positives of dedicated lines can come the risk of the dreaded ground-loop, which is often accompanied by subtle to loud 60 cycle hum heard from the speakers. This can occur when multiple dedicated lines are installed without any attention being paid to grounding issues. Without getting into great technical detail, the solution is to ensure that the dedicated lines are all equal in wire length and that the ground wires for each are the same wire gauge. You want to achieve an equivalent impedance to ground through each of the respective lines.
If necessary the electrician can cross and fasten the wire from side to side in a ceiling joist or between the walls to insure that the wire from the closest outlet to the panel is as long as the farthest wire run from the panel. This is a far better alternative than the band-aid solution of floating the ground pins from electronics to the outlets.
Over-rated
Everything about a dedicated line from the breaker, outlet, panel and power-system should be electrically over-rated for best performance. It is not a waste of time or money to use 10 gauge wire, a 20A or 30A breaker, 20A outlets and, when possible in a new home construction — a dedicated system sub-panel. Electricity does not behave like water that flows calmly through a hose under moderate pressure. AC power is dynamic and complex as it pulses and reacts with the various types of power supplies.
An End Point: Electrical Panel
The electrical panel is where all the circuit breakers are located. From a realistic perspective, the panel represents the end point of influence over the sound of a recording system. Once again, dedicated and over-rated breakers at the electrical panel are a good starting point in maximizing the DTCD® to a high performance A/V system. Placing the breakers on the same phase of the AC panel will also render a benefit in sound and system performance. Select the electrical phase that has the fewest number of electrically noisy devices. For instance, avoid using the phase that has constant running electronics such as refrigerators, freezers, aquariums or other noise-producing motors etc.
Superior System Protection
Very few people are aware that a relatively low cost protection system that can be installed easily by a qualified electrician at the AC panel. This protection system is loosely termed “whole house surge and spike protection”. This is a low-cost installation that protects not only home or commercial recording systems, but everything in the home or business that is connected to the electrical panel. These devices come with an LED system that alerts the customer if the system has been compromised, at which time an inexpensive replacement system is available. What this means is that once again, there are low cost options available to consumers that allow the focus to fall on performance rather than concerns over protection. Even though almost all power conditioner or distribution devices protect systems to some extent, the BEST surge protection is at the electrical panel where the path to ground has the least impedance.
The Best Low Cost Improvement to the Power SystemSince DTCD® is the most critical element to any power system’s performance and effectiveness, the many connection points in the system become paramount. If any of the connections in a power circuit are loose or compromised they will limit DTCD® and introduce noise onto the AC line. It is worthwhile to have a qualified electrician check and tighten the screws to the breakers and the buss bars. While he is there have him replace the AC outlets with heavy-duty units and check the wires for corrosion.
It will also be helpful to replace breakers that have tripped because they can become degraded and trip below their intended rating; they can develop carbondeposits which can introduce power line noise. With these simple maintenance tasks there will be an immediate and pronounced improvement to total power system performance.
The Importance Of Electrical Delivery To Recording And Sound Systems
Before examining methods of setting up an ideal electrical delivery system for recording, music and sound reproduction, it helps to understand why electrical conditions have a profound impact on sound. Too often, the AC system is misunderstood in its relationship to the performance of recording or playback systems. This can lead to the misapplication or over-application of AC treatments — or the extreme of ignoring the power-delivery system as inconsequential altogether. In both cases a corruption of the system’s most fundamental signal will be the result.
The Source of Sound
When referring to a playback or recording system’s “source” most people will make a reference to the actual media, whether it is voice, instrument, a record, CD or tape. However, from the perspective of electronics systems there is a far more fundamental, underlying “source” than the media being transported through a recording or replay system.
The actual source of what we hear in any recording or playback system is the power as supplied from the wall after being rectified by the power supply into a ;relatively stable DC source. It is this DC power source that is the fundamental energy source that makes soundpossible. For example, in an amplifier it is the DC source current (modulated by the signal source) that drives the coils in a speaker. If the powersource is unstable or contaminated then the output will be as well regardless of the information in the signal source. If the AC power varies or if there’s some anomaly in the power source it will show up clearly in the audible range. The assumption that power supplies provide perfect noise-free DC voltage that does not vary under load, is fanciful at best, complete fiction at worst. There is no such thing as a perfect power supply capable of filtering, blocking or managing multiple forms of high-frequency EMI and RFI interference produced by electronics systems. In the simplest terms, alternating current represents the foundation of reproduced sound in recording, sound and music systems.
A Historical Brief
For years, the predominant approach to an AC system was to install a large, usually heavy, multi-outlet box with some type of massive low-pass filter ie: transformer, choke or coil. These were designed with the view that AC delivery is a simple, low-frequency event requiring protection onlyfrom external, grid-related sources of high-frequency noise, line spikes and voltage surges. These boxes were viewed as virtual brick walls, keeping out all grid-borne noise, surges or spikes that posed challenges to the performance and safety of electronic systems. However, two principle issue were overlooked. The primary issue with the low-pass filter or regenerator approach lies in their inability to deliver instantaneous peak current impulses to full-wave bridge-rectifier or digital switching power supplies in the time in which they would normally receive them from the wall. The second and equally important consideration is the fact that these one-way noise rejecting designs also block noise generated by the components themselves, reflecting that noise back to the other components in the system.
Upon Close Inspection
Electronic power supplies don’t pull current in a linear fashion like a light bulb, fan or simple motor would. The full-wave bridge rectifiers and digital switching supplies in electronics draw hard on the AC line, pulling instantaneous bursts of current off the highest and lowest peaks of the sine-wave. This happens within milliseconds in order to fill power supplies storage capacitors. Both full wave bridge rectifiers and digital switching supplies create a significant amount of noise during this process that extends in frequency to the 50th harmonic of the line frequency. What this means, is that from the perspective of power-supply, AC transmission is a near-field, high-frequency occurrence not a low frequency 50-60Hz event.
With this basic understanding of the role AC plays in sound and the high frequency noise electronics systems create, two key elements emerge that are paramount in building an ideal power-system: Dynamic Transient Current Delivery™ (DTCD® ) and Component to Component Interference™ (CCI™).
DTCD® — Dynamic Transient Current Delivery
Maximizing the unimpeded instantaneous and continuous flow of current to electronics is critical to recording and playback systems performance. Recording and sound playback electronics are designed to perform optimally through an unrestricted interface with current. This is as true for source electronics as it is for amplification. Placing anything in front of an electronics system that restricts, impedes or slows the DTCD® of AC power will degrade the ultimate performance of the system. This is why most electronics manufacturers discourage the use of power conditioners that interfere with instantaneous current flow. Starting at the AC panel there are simple methods and measures anyone can implement to improve their entertainment system’s instantaneous access to its power source without compromising protection or performance.
CCI™ — Component to Component Interference
A primary concern when building an electrical delivery system for recording or sound should be the isolation of individual components from the high-intensity fields of EMI and RFI noise that saturate the space surrounding electronics systems.
The power supplies of sound and recording electronics are by nature interconnected and in close proximity to one-another. All components in these systems have a unique electrical footprint and out-put noise from their digital switching or bridge rectifiers within the power supplies. Power supplies generate significant EMI primarily from the switching rectifiers. Digital equipment also generates high frequency RFI.
Both RFI and EMI may be transmitted from one component to another in several ways. The first is through conduction via the power cord connections and through interconnects. The second is through inductive coupling via power cords and other electronics connections.
Not only do power supplies emit a back-wave of noise energy through the ground system and power cords, their digital switching supplies or rectifiers radiate intense fields of gigahertz EMI. This affects all electronics and cabling within their immediate environment.
By far the most effective means of minimizing the impact of this noise lies in treatment of the initial outward points of electrical interface for each component — the power cord and the system’s main distribution points, the AC distribution buss/power conditioners.
A properly designed power cord can act as the first line of defense by isolating the power-supply port and IEC area from the radiated energy that surrounds electronics. They should also act as low-impedance path for the back-wave of power supply noise to reach an exit path from the system. Power cables that have low measurable impedance, resistance and reactance are preferable because they can provide a neutral connection for reactive power supply signatures and allow the cleanest exit path for ground noise to be dissipated/filtered at the connection with the distributor.
The primary role of the power distributor — outside of providing optimal DTCD® and simple protections from spikes and over-voltage — should be to provide a passive exit path for system-generated noise. The best distributors will offer individual component isolation so that the ground noise flowing out from one component does not affect other components plugged into the same AC distributor. It may sound simple and that is the goal. Power distribution should be an uncomplicated delivery path for the instantaneous AC impulses that allow electronics to perform at peak efficiency.
Contrary to popular theory, grid related or external noise generated outside of a systems immediate environment is vastly over-rated as a threat to system performance. Most if not all quality electronics have built in power supply elements that are more than capable of filtering or re-directing incoming noise — which pales in its effect to the massive amount of noise that is generated within the system. Given that the most sensitive electrical elements lie within recording and playback systems, this is a good place to start in building an ideal power-supply chain; one designed to deliver maximum current and minimum AC related distortions.
The fundamental design of interconnects, power cords and power distribution can radically affect EMI and RFI contamination — which in turn will dramatically affect the resolution and detail in recorded or reproduced sound.
Keeping It Simple
If we accept that electronic power supply’s interface with current is a high-frequency, dynamic (short-term) event then it becomes clear that the ideal signal path for current should be direct, with minimum added complexity. Providing simple, unobstructed, low-impedance pathways for current using solid connections and high quality materials will yield by far the most consistent and desirable results. The closer the signal navigates toward electronics the more critical these elements become. Conversely the more complex, obstructed the path, or the more reactive elements that are used between the panel and a system of electronics, the more compromised and unpredictable the results will be. Keep in mind that reducing perceived noise is only valuable if it can be done without restricting or impeding DTCD® . Some may value a reduction of perceived noise to a degree that makes losses in timing, immediacy and dynamics tolerable but when compared to sound that is uncompromised with regards to dynamic content and has noise isolation, the choice is clear.
The power-system components that are easiest to control, such as power breakers, grounding, dedicated lines, outlets, power distributors and power cords should perform two simple functions. Each part of the AC chain should be treated or selected to provide Dynamic Transient Current Delivery™ (DTCD® ) to the electronics or when close to the system itself, to isolate the effects of radiated or conducted electromagnetic interference generated by associated system components.
There are many power cord misconceptions in the market. Here, we will address these issues and how Shunyata Research relates.
How can an aftermarket power cord, which represents the last 6 feet or so of many miles of cheap in-wall and underground wiring, make any difference at all to sound or video?
There are many misconceptions about the basics of power transmission and power quality that make it difficult for people to understand why any aftermarket power cord can impact the performance of a home A/V or professional recording and film system. The fact of the matter is that Shunyata Research power cords have made dramatic differences in all manner of consumer and professional recording, sound and film systems. Many skeptics question even the possibility of an aftermarket power cord making a difference in electronics performance. Shunyata Research is pleased to provide answers.
The first and most obvious question is — can power cords make any difference at all? There is no sense in talking about theories of operation if we ca’t agree that there can be an obvious visual and audible effect when applying a competently designed aftermarket power cord to electronics. Most of the thousands of professionals and consumers that use Shunyata Research power cords started out as skeptics and have answered that question for themselves through their own experience.
The only cases where a high quality power cord may not have a significant effect is when it is coupled with a poor quality power conditioner that creates a high impedance to instantaneous current flow problem. The most common misconceptions about power transmission and their simple technical truths follow:
MISCONCEPTION #1: AC power is like water coming from a large power tank, flowing through several 10s of feet of power hose into a component. This implies that the component is at the end of this system.
Answer: Actually, the component sits between two power conductors: the hot and the neutral. AC power oscillates (alternates) back and forth at a 50-60hz rate. So power does not pour into the component at all. The component’s power supply is within a complex network of wires and connectors. Due to their obvious proximity, ALL of the wire and connectors can and do affect the performance of the component’power supply.
MISCONCEPTION #2: AC power can be contaminated just like water in a hose. This implies that once the water is contaminated at some point up stream, that is must be cleansed before it arrives at the audio component.
Answer: As stated in #1, the component is not a the end of the power hose. It is between two power hoses and the current is oscillating back and forth. Further, current is not like water at all. Electrons cannot be contaminated. There are two aspects to power transmission: the EM wave and the current flow. The current itself cannot be contaminated but the EM wave can be modulated with other frequencies. We usually call these other frequencies noise or EMI. Within the various parts of a power circuit there may be EMI in certain parts that are not present in others. EM energy can be transformed or redirected to lessen their effects.
Some power cords for example, use capacitors, inductors, or ferrites in an attempt to control the EM fields around the audio component. The success of such an approach is completely dependent upon the specific power supply design and its reaction to the added reactive capacitance of the power cord.
MISCONCEPTION #3: There is up to a hundred feet of wire in the walls, so the last 6 feet of power cord can’t possibly make any difference.
Answer: The PC is NOT the last 6 feet as stated in #1 and the local current and EM effects directly affect the sonic performance of the component. The power cord is not the last 6 feet, it is the first 6 feet from the perspective of the component. The further a noise source is from a component, the less of an impact it will have on the components power supply. The high-frequency noise sources that have the greatest impact on audio and video performance are the system components themselves — which are usually all in close proximity of one another and all emit radiated fields of high-frequency noise. A well designed power cord can act as a noise-isolated extension of the primary winding of a component’s power supply and will help isolate the power supply from the fields of radiated RF and EM noise energy that is ever present in all electronics systems.
MISCONCEPTION #4: There is a tremendous amount of electrical interference and EMI coming from outside the home that we need to protect our equipment from. This implies that we need some sort of power conditioner or filter to protect the equipment.
Answer: Most of the EMI that affects the audio quality of a system is generated by the audio components themselves. EM waves that travel through space dissipate in power as the square of the distance from the source and very high frequencies that propagate through the power circuit do not survive for long. Power lines present a high impedance to Mhz and Ghz signals due to the relatively high inductance of power lines.
A primary source of audible sonic degradation is caused by the power supplies. Most components use FWBR (full wave bridge rectifier) power supplies that generate an incredible amount of transient noise when the rectifiers switch on and off. The design of a power cord can significantly affect the reactance of these signals within the power supply. Because the power cord is part of the primary winding of the power transformer, the transition between the various metals used in a PC can cause EM reflections and diode-like rectification of the noise impulses as they propagate away from the power supply. If the PC presents a high impedance to these signals they will be reflected back into the power supply where they will intermodulate increasing the high frequency noise levels of the component. Most power supply filters are ineffective at blocking very high frequency noise components and much of it is passed through to the DC rails. The sonic effects of this include: high background noise levels, blurred or slurred transients and a general lack of clarity and purity of the sound or visual image.
MISCONCEPTION #5: There is some conspiracy among audio designers that keeps them from producing a “proper” power supply that is not affected by the quality and design of a power cord. This concept is like saying that if a speaker were properly designed, you wouldn’t need to use a good quality speaker cable.
Answer: Shunyata Research power cords have been tested with modest beginner and mid-fi equipment as well as the most exotic and sensitive recording devices and electronics. We have yet to find a component that cannot be improved by replacing the power cord with a high-quality design. As long as power supply design is based upon FWBRs or switching supplies, the power cord will always be significant.
MISCONCEPTION #6: High-end power cords just increase the circuit capacitance acting as a high-frequency shunt. There are some power cords that ARE designed this way. Some even insert capacitors within the cable to further increase capacitance. This approach has some positives and many negatives, including the reactive interference with the way many power supplies are designed.
Answer: Capacitance alone cannot account for the differences in a power cord’s performance. There are some very effective aftermarket power cords that have virtually unmeasurable levels of capacitance. These power cables are usually designed around hollow tubes with the conductors inside. The conductors are several inches apart and cannot significantly affect the capacitance of the power circuit.
MISCONCEPTION #7: Power cords are just like speaker cables; the shorter the cable the better.
Answer: A speaker cable conducts an audio signal from the power amplifier to the speaker. The distance is quite small, on the order of a couple of feet to several feet. The quality of a speaker cable is determined by how well it can transmit the signal from the amplifier to the speaker without alteration or signal degradation.
A power cable on the other hand is not transmitting an analog signal. It is conducting A.C. power and its sonic superiority will be determined by its ability to deliver current (steady-state and instantaneous) and its ability to deal with the EMI effects of the components to which it is attached.
Since a power cord is composed of a hot and neutral wire that the component sits between, a change in the length of the cord will increase the size of the “buffer” around the component. In the specific case of Shunyata Research — we use patented noise-isolating geometries, shielding and a patented compound that absorbs EMI in some power cord models. Increasing the length of the cable, increases the noise isolation, or coupling effect to the ZrCa-2000 compounds, therefore increasing the performance of the cable.
In general, Shunyata Research does not recommend a power cord that is shorter than 3 feet or 1 meter in length for performance ease of use and, or resale reasons. Of course, subtle degrees of audio performance are not the only consideration when putting together an audio system. Aesthetics are also important especially when the system is located in a beautiful home. I just point out the performance differences so that people can make an informed decision when determining the optimum length for their cables.
For more than 15 years, Shunyata Research has demonstrated a profound ability to manufacture state-of-the-art products. Designer Caelin Gabriel has developed a line of custom-engineered products that make Shunyata Research a leader in power and signal technology. This document includes the unique concepts, measurements and custom-designed parts that define Shunyata Research’s approach to power distribution in the recording, film and medical industries.
ΞTRON® Patented Technology
The ΞTRON® technology is applied in both PowerSnakes Signal Cables and the reference range of PowerSnakes Power Cords.
Even one SIGMA model power cord will do more than earn its place, they will elevate the entire system to performance levels you may not have though possible.
Vance Hiner, The Audio Beat: August 2015
Shunyata Research scientist Caelin Gabriel’s extensive technical background and years of research deliver a truly ground-breaking technology that literally brings down the price of state-of-the-art performance from power and signal cable systems to a realistic number. The ΞTRON® technology is applied in both PowerSnakes Signal Cables and the reference range of PowerSnakes Power Cords. All of the Shunyata Research cable products that incorporate the ΞTRON® technology will out-perform cables costing five, ten and twenty-times their price. The engineering and detailed process involved in developing this new patent-pending, protected technology is described in detail below. No cable manufacturer has any product, at any price, that will compete with a ΞTRON® treated Shunyata PowerSnakes model power and signal cable. The ΞTRON® technology is applied in both PowerSnakes Signal Cables and the reference range of PowerSnakes Power Cords. All of the Shunyata Research cable products that incorporate the technology will out-perform cables costing five, ten and twenty-times their price. The engineering and detailed process involved in developing this new patent-pending, protected technology is described in detail below. No cable manufacturer has any product, at any price, that will compete with a ΞTRON® treated Shunyata PowerSnakes model power and signal cable.
ΞTRON® Technology
An electrical conductor that has an alternating signal that propagates across its length will generate an electromagnetic field that surrounds and interpenetrates the conductor. A dielectric is a material that is not electrically conductive and is used to insulate conductive surfaces and wires. Dielectric materials are sensitive to electric fields and demonstrate an effect called dielectric polarization and dielectric relaxation. In essence, a dielectric may store and release electric field energy when exposed to an alternating electric field. Dielectric materials are used to insulate conductors (wires) and are also used in the construction of capacitors. Fig. 3 is a cross-sectional view of a simple, single wire. 301 is the signal conductor. 302 is the insulating dielectric material. 303 is a conductive shield. When a signal is transmitted through the wire, it generates an electric field around the conductor as represented by the arrows. The electric field from the conductor causes a polar movement of the molecules within the dielectric as represented by the positive and negative symbols. The dielectric stores an electric charge by way of this molecular polarization. When the signal is removed or changes direction, the electric charge reverses and the stored charge within the dielectric will be released. The electric field generated by the dielectric induces a current within the conductor, which distorts the original intended signal.
A Summary
The technology reduces dielectric distortion within a signal wire by neutralizing the electric charge differential between the signal conductor and the insulating dielectric material. This is accomplished with the use of a conductive shield that surrounds the signal wire’s dielectric material. The electric signal carried by the conductor is also imposed upon the shield through an electric field compensation circuit. The electric field of the conductor and the electric field of the shield oppose one another and create a near zero equivalent electric force within the dielectric material. This effectively neutralizes the charge/discharge distortions created by the dielectric material in the presence of an alternating signal. Since the conductor and shield both carry the signal electric field, they dynamically track the varying alternating signal to create a continuous net zero charge differential within the insulating dielectric. The ΞTRON® electric field compensation circuit allows the signal’s electric field to be imposed upon the shield, while at the same time limiting current flow and eddy currents within the shield. While the invention uses a conductive shield around the signal conductor, it is not used in a conventional manner. A cable shield is conventionally used to shield RFI/EMI by connecting the shield to a ground pin, ground wire or grounding surface. The shield as used in the ΞTRON® technology cable is not connected to any other wire, grounding wire, or grounding surface or any other conductive surface. The shield is used exclusively to create an opposing electric field within the wire’s insulating dielectric material.
Patent # US 8,912,436 B2
Date: December 2014
Description of the Drawings
In Fig. 3 only the signal conductor carries the transmitted signal. This creates a dielectric polarization of the insulating materials that surrounds the conductor. In Fig. 4 the signal is carried by both the signal conductor and by the conductive shield. The signal on the shield creates an electric field that opposes the field generated by the center conductor. These two electric forces oppose on another and prevent a net polarization of the dielectric material. Fig. 2 illustrates a simple shielded wire that demonstrates an implementation of the invention. The electric field compensation circuit (EFCC) is connected to the signal conductor 101 with other end of the EFCC connected to the conductive shield 103. At the other end of the wire, the signal wire 108 is connected to the EFCC 110 with the other end of the EFCC connected to the shield 106.