Rule 7 - Electrical conditioning
Enable electrical isolation and power line conditioning
Mitigating the effects of Electromagnetic Interference (EMI), Radio Frequency (RF) interference, and Ground Loops from the AC power lines will remove the veil for a clearer soundstage.
Most home environments are saturated with Radio Frequency energy coming from broadcast stations, AM/FM radio, and satellite transmissions. With the advent of broadband 5G, a massive expansion of the digital world has come upon us with Wi-Fi, Bluetooth, smart television, smartphones, and other wireless-enabled sensors. These energies may migrate into the AC power lines and be modulated as noise interference. EMI shielding becomes more important as frequencies increase, and so does interference. AC mains frequency variations can exceed 0.2% over a matter of minutes and this can cause speed variation in synchronous motors like turntables or tape devices. The AC power line may also suffer brown-outs, voltage fluctuations and spikes from local loading effects, and surges from lightning strikes.
A power line conditioner is a device that may be used to clean AC power lines against extraneous interferences, maintain the integrity of the voltage to deliver constant power, and protect audio equipment from dangerous voltage spikes. The genesis of a power line conditioner was a simple ‘power strip’ designed to accommodate multiple power appliances as a practical and safe electrical organizer in the home. With more people using composite audio systems at home, the commercial power strip evolved to include surge protector circuitry. With the advent of the computer industry, the power strip further included filters against digital noise. Today’s commercial AC power strip includes surge and noise filters as standard fare. Popular commercial brand names such as Tripp Lite, Belkin, Panamax, Furman, Pyle, etc., will meet the basic need for audio use. The problem is which ones to use for high-end audio. The following design factors and implements offer guidance so that you can make a better choice to suit your audio requirements.
Surge protection
Voltage surges and spikes may occur in electrical lines that can directly affect the safety of your equipment. An impulse protector is used to suppress large voltage pulses into the network. It can break the connection with the input line to defend the audio components against damage (non-sacrificial type). However, most would have to be replaced because the circuitry would be damaged in the process of defending the surge (sacrificial type). However, in extreme cases like a lightning strike, the surge will arc over the circuitry and unfortunately damage the other electrical components connected to it.
Lightning arrester
Generally, there is nothing that power line conditioners can do about lightning strikes. At best the surge protectors, isolation transformers, and power regeneration units may only mitigate some damage provided the lightning strike is further away from the house. Most of the time, the surge is so extreme that it will arc across (overwhelm) the surge protector and into the electrical system causing considerable damage to electrical appliances and audio components. However, the only solution to mitigate the damage that will inevitably happen is to install a lightning arrester by a service professional outside your house in the open. The grounding rod will have to dig deep and the arrester will have to fly high. Unfortunately, this may be good for a single strike where you would have to install a new arrester set every time it hits. But the good news they say is, that lightning doesn’t strike at the same place twice.
Pi-Filter
Noise removal
Electrical motors, power tools, air conditioners, generators, motors running from refrigerators, washing machines, dryers, and the like generate pulses when in use. These “dirty” alternating currents coming from the electrical outlet are modulated by audio components. A basic feature in a power line conditioner known as a noise filter (aka pi-filter) is used to suppress extraneous noise (caught on wires) and other interference. They would help eliminate radio frequencies (RF) from radio/TV stations and electromagnetic interference (EMI) that may occur in the electrical lines caused by wireless devices which is a daunting problem today.
Isolation transformer
An isolation transformer (see illustration) may also be used as part of the line conditioner for electrical noise suppression. The transformer breaks ground loops that caused additional currents (considered noise) in the line. The transformer coil in theory may further suppress surges. An isolation transformer is an ideal solution for noise suppression and avoiding ground loop situations.
Line voltage regulator
Auto or manual voltage regulators may be included in the line conditioner or as a stand-alone to normalize the output voltage of an allowable range to meet certain equipment requirements. This is useful if your area has severe voltage fluctuations or brownouts that may damage or render the equipment unstable. There are many instances when overheating is caused by the extra voltage delivered by the current. The regulator may remove a constant part of the input voltage that is causing overheating of the transformers in the power supply unit of an audio component. However, they are not recommended for power amplifiers.
Voltage stabilizer
They use very large transformers to offer constant voltage. When in operation doing their thing, they will be noisy and heat up easily. They have stiff electronics with a transformer and large capacitors to stabilize the voltage. Because power amplifiers are dynamic devices feeding off instantaneous high currents when required, the stabilizer may constrict the supply. Not recommended for high-end audio use.
Power amplifiers are finicky components
Power amplifiers are dynamic range components that draw the power which it needs and when it needs depending on the recording material and efficiency of the loudspeakers (load). That’s why we advocate for more power headroom in the case of power amplifiers that may be hungry for current. Therefore, I do not recommend using power line conditioners and the like which in my humble opinion will worsen the situation because of the restrictive filters that will inevitably saturate. However, you may consider using specially designed ‘active power regenerators’ such as those manufactured by PS Audio or companies that provide mains re-construction. These products convert your existing AC into DC and then convert it again into ‘new’ AC and regulate the voltage. This method rids the inherent noise from your outlets with a reconstructed waveform. If the system employs a large enough transformer with very low impedance and keeps the efficiency during the conversion will allow for peak output pulls and not restrict dynamics. Nevertheless, be prepared for a very large and heavy chassis.
AC line management
Check the integrity of your AC wiring
The first thing you need to do is to check if your wall outlet cables are configured correctly i.e., the hot is correct and the ground is operational. You can use a voltage tester to check if the cables are properly oriented.
You must connect your power plug so that the live wire is going into the input side of the transformer which should be the case. This is important because all transformers are constructed in a manner that if they are connected with the ‘hot’ into live input, they will make the lowest possible noise. This is normal as the industry has allowed for a small amount of leakage.
Identify the extent of electrical leakage
For all electrical audio components especially the ones with two-prong plugs, measure the amount of voltage leak on the chassis. Disconnect all the interconnects except for the power cable for each component. Use a voltage tester and set it to DC, use one test prong on an active earth ground (power line conditioner chassis) and the other test prong on the component’s chassis, and record the voltage reading. Switch over the component's power plug (live and neutral) using a cheater adapter to the opposite side and measure again. The orientation with the lowest reading is preferred. Adjust the cable orientation on the plug as needed with earth ground connected where possible. Do this exercise for all your components.
Evaluate your power line conditioner
Power line conditioners may be evaluated with an ‘EMI Meter’ to test their effectiveness. Companies such as Greenwave (Broadband), Stetzerizer (Line), AudioPrism (Noise Sniffer), Entech (Noise Analyzer), etc, offer inexpensive portable units to test your AC noise level. First, check the noise level at the wall outlet that you are going to use. The recommended reading as suggested by Greenwave should be no more than 25 multi-Volts which is the safe gold standard or other standards suggested by the respective device manufacturer. Next, plug in the power line conditioner and test the effectiveness of all available outlets on the conditioner and compare both noise values off the wall and from the conditioner.
Predictably, most budget conditioners will not show significant noise reduction and would nonetheless remain a useful power line organizer for your array of power cables. It is important to switch off all power appliances like washing machines/dryers or lighting dimmers that you would not normally use during your listening session to enable a practical measure for line noise pollution. If the noise of the wall is significant, try and locate the source(s) to understand the problem by using the principle of deduction. When you have identified it, make a decision either to remove, relocate as far away as possible, replace, or turn off the culprit(s). Once done, you have to re-measure and verify the reduction for an acceptable/tolerable level.
Note: EM meters may have different ranges that they measure and some models have a smart display to analyze the data further. Readings may differ at different times of the day; this is because contamination is unpredictable and may set in any time of the day depending on the activity of your surrounding neighborhood.
Other filtering gadgets
Greenwave, Stetzerizer, PS Audio (Noise Harvester), iFi, etc., also make small plug-and-play filters. Just plug them parallel next to the wall outlet or an outlet of your power line conditioner to bring the noise level lower. It is said that 2 or more of these gadgets would lower the level. Other power management systems such as a “Power Perfect Box” or the like are available to cure the ills of AC line noise. Search the digital highway for a professional that does this for a living.
Additional protection from HF noise
It is commonplace to see that manufacturers are providing ferrite chokes that come built into the stock power cord for computers, televisions, or digital players. Ferrite is a ceramic magnetic material used to make choke filters for RFI suppression. The type of ferrite used for RFI suppression is specially designed to absorb RF energy over a broad frequency range, such as HF or VHF. Ferrite is available in many different mixes of composition that absorb best in a particular range. It is also available in many different forms; rings (toroids), rods, and beads. A popular design is a Snap-on rectangular block with a hole in the middle to accommodate the power cable. The plastic case holding the ferrite snaps onto the cable in place to form an RF choke which prevents RF signals from flowing along their outside surfaces. The placement of these devices is best at the receiving end of the power cord just before the component’s receptacle.
Hum and Buzz Management
High frequencies buzz
For high-frequency buzz, you may be affected by RF or EMI. Your connecting cables (power cables and interconnects) may not be sufficiently shielded or your cable layout is suspect (audio signal lines and power lines are running parallel to each other) and therefore susceptible to interferences. To detect the source, turn off the volume knob and hear if the noise goes away. If it does, unplug all the front-end components leaving one, and try again. Do this exercise one component at a time (deduction principle) until you find the source of the noise with the volume up. If your interconnect is very long (more than 1.5 meters) and the signal it carries is very low (e.g., turntable to phono stage) this can be a problem. Use balanced interconnects for longer runs if possible. Sometimes it could be your amplifier, especially class ‘D’ amplifiers that are notorious for poor signal-to-noise ratios. It could also be a bad design tweeter/crossover which may be an unlikely scenario for high-end audio components.
Low-frequency hum
Depending on where you live, you may be experiencing a ground loop (low-frequency hum - 50 or 60 Hz) within the system. Switch off the system. Check to ensure that all your audio components that have ground are safely grounded and there are no damaged cables. Your audio components may not be grounded accordingly or one or more audio components are drawing power from a different phase (multiple paths to earth) from your circuit breaker box (ELCB). Use only one power outlet (single-phase) with a common power line conditioner for all your audio components.
To confirm if you have a ground loop, turn off the volume knob and hear if the hum goes away. If it does, unplug all the front-end audio components leaving only one, and turn on the volume again. Do this one component at a time (deduction principle) until you find the source of the hum. Once located, if it’s a 2-prong plug type component, try using a 14-gauge single cable to ground the component on its chassis and direct it to the power line conditioner chassis ground. If it's already grounded, lift off the ground cable and test again. If unable to solve, consider an isolation transformer for the problem component. Hum may also be due to differing circuit designs or equipment faults. Do not use an artificial ground cable directed to literal mother earth or a box of sand, it will not work.
A quality Power line conditioner deserves a quality companion power cord for the input as well as the outputs to other audio components. It is perhaps one of the most impactful upgrades you can make to an audio component. It has been said and argued that all power cords sound the same and do not improve the sound. These Nay-Sayers out there or audiophiles in name only (Ai-No) or maybe home theatre enthusiasts are not particular about sound quality. Some may argue, why bother with the one-meter cord when you have over 20 meters of industrial power cable running from the distribution box and down to the wall outlets that are not audiophile grade? But I say to them, we are not bothered by the over 20 meters run but by the first meter that the line conditioner or the audio components’ see. This may be likened to your water filtration system at home that uses filters to make your drinking water cleaned from impurities, likewise, the power cord protects, and the line conditioner filters the noise from breaking through.
The industrial electrical cables supplied to your home are safety tested, approved by professional engineers for use, and are suitably shielded inside the wall or through metal conduits according to regulations and professional best practices. It is the cables off the wall that is exposed and vulnerable to EMI, RF interferences, cross-talk, ground loops, and other safety hazards. The power cord's primary job is to conduct instantaneous current otherwise you reduce the amount of current available to the power supply. Electrical technicians use an electrical measurement device called a ‘short circuit current analyzer’ to measure instantaneous pulse i.e., how much current is available at the outlet. It is said that, if 1.5-kilo amps of peak current are measured at the outlet, a stock power cord plug into the system may bring the peak current to a 0.6 drop of almost 50% of the available current. Therefore, a heavy gauge power cord with proper shielding and tight connections is critical to maintaining the integrity of the current push when needed. Moreover, stock power cords are not suitably shielded when compared to the high-end industry ones. This can be easily measured by a relevant electrical test device to understand how much noise is emitted when the cords are live. The greater shielding will also mitigate audio signal cables that are near power cords from being susceptible to noise-induced distortions.
Amps vs Wire Gauge
There is a direct correlation between cable length, amperage, and wire gauges. The following table provides a breakdown of the relationship between amperage and wire gauge. These are basic guidelines relevant for use in a high-end audio setup, so as the length of the cord is increased either the amps will decrease or the wire gauge will have to be increased. The more resistance there is in a cable the less electrical current will flow. Make sure your plugs can practically accommodate the different wire gauges and several wires (conductors) inside the power cord. The following table is instructive:
Note: The lower the gauge number, the thicker the conductor.
A dozen recommended tips and tweaks
Run a dedicated line (10 AWG) off the Earth leakage circuit breaker (ELCB), ideally from the incoming power grid to a dedicated circuit breaker to the listening room with its breaker from a ‘phase’ that is not busy (32 amps recommended). This way it’s not sharing the same network with the rest of your household appliances hence fewer interferences. All 3 conductors should be of the same gauge and ideally run through a metal conduit that is grounded. All 3 conductors should be connected individually (star method and not looped) from the breaker to the outlet.
2. If you are unable to run a dedicated AC line, use only one wall outlet for the line conditioner and plug all your front-end components into a common power strip from the line conditioner outlets. Amplifiers should be plugged into wall outlets direct with the same phase as the line conditioner, otherwise plug them into outlets on the power line conditioner that is labeled for high current or bypass, which means there are no filters in the pathway. Moreover, you will enjoy the benefit of quality sockets and surge protection if there is one.
3. When choosing a power line conditioner, make sure it comes in a metal housing for classic shielding. EMI shielding and earthing are very important. The area where the cable shield is connected to the chassis earth is critical. The connection must have low resistance.
4. Audio components are sensitive to contact resistance because they need to have instantaneous current delivery on demand, especially the rectifiers found inside components. Therefore, the plug connections should be tight with good soldering instead of crimped. Ideally, you should use hospital-grade AC plugs, power line conditioners, or power strips. If it’s good for the hospitals, it should be good for the audiophile.
5. Loudspeaker cables are not usually shielded, you may apply a Snap-On ferrite block on the positive side only of the loudspeaker cable nearest to the loudspeaker’s cable terminal to defend against EMI and RF interferences.
6. Power cords should be well made, well shielded, and with a heavy gauge conductor (minimum 14 AWG or better 12 AWG) for its length to carry high currents, with quality plugs (hospital grade) and tight connections that will not spark or come loose over time.
7. Change all switching power supplies to a linear type of power supply. Identify the output voltage and amperage on your stock power supply and get a quote today, they are not costly on the internet and will provide a much better return for your investment. You should be able to hear a tangible difference if all things are equal.
8. Keep cables off the ground, and never run cables in parallel with other cables, if they should cross, cross them at right angles. Audio interconnects should be physically separated at least 3 inches apart and kept as far away from power cables.
9. Do not use or switch off lamp dimmers, fluorescent lamps, or any lighting requiring an electrical ballast (transformers) when engaging in critical listening, they are notoriously noisy and a primary source of electrical interference. Also, remember to switch off your washing machine or dryer when listening. If you need to switch on dimmers, set them at full brightness as that will lower the noise emission.
10. Your circuit breaker (ELCB) should be of a high-quality type. You should check the ELCB to ensure that the power line-in locking mechanism is tightened at least annually, they come loose over time because of vibrations inherent within the system. You need to have a licensed electrician to do this. If your breaker has tripped a few times under load you might want to change the entire breaker because the contacts would then be suspect.
11. Use balanced interconnects for runs more than 1.5 meters.
12. All excess wires/cables should not be coiled when dressing them, let them run loosely but well away from other cables. Ideally cut them short for practical use.
Conclusion
Fire up your system, and turn the volume to your normal listening level. At about a meter away from each loudspeaker, without any music playing listen at ear level from each loudspeaker's approximate acoustic center for any buzz or hums emanating from the loudspeakers. If there is, read this article again. Once your audio system is exorcised, you can now begin to enjoy the subtle details of musical performance and hints of the recording venue. You should be able to see spatial images more clearly as they seemed to occupy a darker space which is possible when you have substantially lowered the noise floor.