My clean power adventures go back to the writings of Enid Lumley in The Absolute Sound, beginning, as I recall, in the early 1970s. It was Enid who introduced me to the idea that the sound of an audio system could be improved by properly orienting two-pronged 120-volt electrical plugs with respect to the wall outlet. For those of you lacking the original Absolute Sound magazines, many of Enid's findings/recommendations were later documented in Laura Dearborn's 1987 book, Good Sound, which is still commonly available new or used and which has a lot of hard-to-otherwise-find-today good advice for audio system set up, especially with respect to analog-based systems.
Different Sound vs. Better Sound
As with the audible effects of cables and mechanical isolation, many audiophiles view electrical power treatments and tweaks with a sizable degree of cynicism. I think that’s a healthy attitude. There are a lot of companies chasing a shrinking market. Buyers need to be able to separate marketing claims from true performance enhancements.
With audiophile tweaks you should remain skeptical unless you personally can clearly hear a sonic difference and positively classify that difference as not only different, but “better.” Most anything you do to a high-resolution audio system will make a perceptible difference in the resulting sound. But in many cases, differences are just that, mere differences, which one cannot be confident in classifying as "better" sound.
What is "better" sound? For me, from what I believe to be well-made recordings of unamplified instruments in good acoustic spaces, “better” encompasses, among other concepts, a more natural (as in true to what you would have heard live from a good audience seat during the recording session) frequency balance, a more open and organized sound field, more distinct and rounded instrumental and vocal images, “blacker” background, wider perceived range of macro-dynamics and more nuanced micro-dynamics, and subjectively lower distortion of all types, especially high frequencies nasties.
When I speak of "better" sound from here on, or talk of "improvements" in the sound, that's the meaning of "better" I intend. You may disagree as to what constitutes "better" sound, but I hope this definition clarifies what I mean by "better" in my comments.
Since I first began tinkering with audio tweaks which focused on AC power, I have discovered a number of helpful techniques, but also a number of what I deemed to be "blind alleys"—techniques which, while producing different sound, I judged did not in the end produce better sound.
Starting at the Beginning: Dedicated Home Electrical System
Many of those who find that the quality of the electrical power you feed your audio system can make the resulting sound better or worse believe that tweaks to the power quality should start as far back as you can control—your home's electrical service box.
The home I lived in from 1994 to 2014 was one which I built to have a dedicated basement audio room. I also specified a dedicated electrical system for that audio room.
I specified 400-amp electrical service for that home. The 400-amp service was split into two 200-amp panels just past the service entry. The exclusive job of one of these 200-amp panels was to feed 10 dedicated circuits in the listening room. All wiring was three-wire 10-gauge solid copper. The wiring for each circuit was separately conduited from the service panel to a single quad of metal-boxed outlets in the audio room. The outlets were Hubbell hospital grade 20-amp outlets and all circuit breakers were also 20-amp rated.
I used up to six of the available 10 circuits. For example, if my system was bi-amped, I tended to use four high-power monoblock amps to do this. I would give each monoblock its own circuit, then assign the analog front-end components to a fifth circuit, and the digital front-end components to a sixth circuit. If I was not bi-amping, then a stereo amp or just two monoblocks were used and I would only use a total of four circuits.
All grounding and neutral wires for these up-to-six circuits were star-grounded back to the same post in the service box which holds the incoming ground wiring: there was direct copper-to-copper wire connection between all the grounds used by the audio system and the incoming ground wire. The grounds were referenced to an 8-foot solid copper post driven into the ground just outside the service entrance, and were bonded to a cold water pipe just above floor level some 50 feet away. All other unused ground wires for that dedicated 200-amp service box were disconnected and insulated from the service entrance and the circuit breakers for the unused circuits were open.
The six circuits used were all attached to the same phase of the incoming electrical service. A home's 220-volt service is made up of two 110-volt phases. By removing the panel covering the electrical buss inside your electrical service box, you can see which circuits are attached to which of the two incoming phases of power (usually the two fat black wires, the service ground being a fat white wire). I used such a visual inspection to determine which circuits to use with my audio system. With my electrical service panel, the electrical buss in the service panel was physically arranged so that the tabs of the buss fed by each phase were interleaved vertically in the box. Thus, the two circuits which were horizontally at the same level on the buss were fed by one phase, while the two circuits above or below that in the buss were fed by the other phase of power.
Since the 10 circuits in the box were arranged in two vertical rows of five, of the ten available circuits, up to six easily could be placed on the same incoming phase of power. To get these circuits all on the same phase of power, I just manipulated the hot wires for each circuit at the electrical service box so that the hot wires feeding the chosen outlets in the audio room were attached on the service buss to breakers which were fed by the same electrical phase. The original hot wires were long enough for such manipulation without adding any pigtail connections.
In that former house, as much as possible of the electrical equipment in the rest of the house which experience showed can cause electrical interference with audio (e.g., water softener, sump and ejector pump, furnace fan, other audio and video equipment, sprinkler and alarm systems, the lights in the listening room) were connected to circuits which are powered from the other phase of the incoming electrical service, the phase not used by the six dedicated circuits I use in the listening room. (I determined the phasing of circuits powered by the home's other electrical service by measuring voltage between the hot slots of the audio room's dedicated outlets and the hot slots of outlets powering the audio room's lights; a 220-volt measurement would show that two different phases were involved.)
For serious listening, I unplugged many electronic items not in the listening room such as all other stereo systems, my computer, and any item powered by a "wall wart" AC transformer; I also "de-tuned" all TV, satellite, and AM and FM radio receivers so that all that was received by these was random noise. Enid Lumley also made these suggestions all those years ago in her TAS writings.
One of the reasons I chose a basement listening room for my former home was to minimize RFI with the audio power and components. Putting as much of the wiring and audio space below ground level as possible cut down on radio frequencies in the audio space. The room's poured concrete walls also helped this goal. For example, per Enid Lumley's suggestion, I determined that an AM radio detuned to the bottom of the AM band produced mostly pink noise anywhere in my audio room, even near wiring. In contrast, in other areas of the house, bits of station programming in addition to hum, static, and cyclical loud noise products were audible from the AM radio even in the middle of a room, not only when placed along house wiring or next to electrical or appliances and electronics. This was well before my home or most homes used Wi-Fi and before the ubiquity of cell phones, much less smart phones. For many years I only ran FM signals into the audio room via shielded coax, not even routing wired satellite TV or cable signals into that space.
In 2010 my first wife of 34 years passed away unexpectedly. In 2015, my new wife and I moved into a new home in a different city. It was an existing older home, built in 1904. My music room by choice is now above ground with sunlight available through the window during the daytime. While I'd found that a dedicated audio electrical system is not a panacea, I viewed it as a worthwhile investment in an older home where the electrical system was largely an unknown. At least the electrical service had been upgraded to 200-amps with a modern circuit breaker panel during an earlier remodeling by the prior owner. Thus, one of the first home improvement projects we undertook was to install two dedicated circuits into the audio room. As before, this step, while not cheap to retrofit into an old plaster-walled house and not a panacea, is definitely worth the investment in terms of better sound quality.
[Continued below]
Different Sound vs. Better Sound
As with the audible effects of cables and mechanical isolation, many audiophiles view electrical power treatments and tweaks with a sizable degree of cynicism. I think that’s a healthy attitude. There are a lot of companies chasing a shrinking market. Buyers need to be able to separate marketing claims from true performance enhancements.
With audiophile tweaks you should remain skeptical unless you personally can clearly hear a sonic difference and positively classify that difference as not only different, but “better.” Most anything you do to a high-resolution audio system will make a perceptible difference in the resulting sound. But in many cases, differences are just that, mere differences, which one cannot be confident in classifying as "better" sound.
What is "better" sound? For me, from what I believe to be well-made recordings of unamplified instruments in good acoustic spaces, “better” encompasses, among other concepts, a more natural (as in true to what you would have heard live from a good audience seat during the recording session) frequency balance, a more open and organized sound field, more distinct and rounded instrumental and vocal images, “blacker” background, wider perceived range of macro-dynamics and more nuanced micro-dynamics, and subjectively lower distortion of all types, especially high frequencies nasties.
When I speak of "better" sound from here on, or talk of "improvements" in the sound, that's the meaning of "better" I intend. You may disagree as to what constitutes "better" sound, but I hope this definition clarifies what I mean by "better" in my comments.
Since I first began tinkering with audio tweaks which focused on AC power, I have discovered a number of helpful techniques, but also a number of what I deemed to be "blind alleys"—techniques which, while producing different sound, I judged did not in the end produce better sound.
Starting at the Beginning: Dedicated Home Electrical System
Many of those who find that the quality of the electrical power you feed your audio system can make the resulting sound better or worse believe that tweaks to the power quality should start as far back as you can control—your home's electrical service box.
The home I lived in from 1994 to 2014 was one which I built to have a dedicated basement audio room. I also specified a dedicated electrical system for that audio room.
I specified 400-amp electrical service for that home. The 400-amp service was split into two 200-amp panels just past the service entry. The exclusive job of one of these 200-amp panels was to feed 10 dedicated circuits in the listening room. All wiring was three-wire 10-gauge solid copper. The wiring for each circuit was separately conduited from the service panel to a single quad of metal-boxed outlets in the audio room. The outlets were Hubbell hospital grade 20-amp outlets and all circuit breakers were also 20-amp rated.
I used up to six of the available 10 circuits. For example, if my system was bi-amped, I tended to use four high-power monoblock amps to do this. I would give each monoblock its own circuit, then assign the analog front-end components to a fifth circuit, and the digital front-end components to a sixth circuit. If I was not bi-amping, then a stereo amp or just two monoblocks were used and I would only use a total of four circuits.
All grounding and neutral wires for these up-to-six circuits were star-grounded back to the same post in the service box which holds the incoming ground wiring: there was direct copper-to-copper wire connection between all the grounds used by the audio system and the incoming ground wire. The grounds were referenced to an 8-foot solid copper post driven into the ground just outside the service entrance, and were bonded to a cold water pipe just above floor level some 50 feet away. All other unused ground wires for that dedicated 200-amp service box were disconnected and insulated from the service entrance and the circuit breakers for the unused circuits were open.
The six circuits used were all attached to the same phase of the incoming electrical service. A home's 220-volt service is made up of two 110-volt phases. By removing the panel covering the electrical buss inside your electrical service box, you can see which circuits are attached to which of the two incoming phases of power (usually the two fat black wires, the service ground being a fat white wire). I used such a visual inspection to determine which circuits to use with my audio system. With my electrical service panel, the electrical buss in the service panel was physically arranged so that the tabs of the buss fed by each phase were interleaved vertically in the box. Thus, the two circuits which were horizontally at the same level on the buss were fed by one phase, while the two circuits above or below that in the buss were fed by the other phase of power.
Since the 10 circuits in the box were arranged in two vertical rows of five, of the ten available circuits, up to six easily could be placed on the same incoming phase of power. To get these circuits all on the same phase of power, I just manipulated the hot wires for each circuit at the electrical service box so that the hot wires feeding the chosen outlets in the audio room were attached on the service buss to breakers which were fed by the same electrical phase. The original hot wires were long enough for such manipulation without adding any pigtail connections.
In that former house, as much as possible of the electrical equipment in the rest of the house which experience showed can cause electrical interference with audio (e.g., water softener, sump and ejector pump, furnace fan, other audio and video equipment, sprinkler and alarm systems, the lights in the listening room) were connected to circuits which are powered from the other phase of the incoming electrical service, the phase not used by the six dedicated circuits I use in the listening room. (I determined the phasing of circuits powered by the home's other electrical service by measuring voltage between the hot slots of the audio room's dedicated outlets and the hot slots of outlets powering the audio room's lights; a 220-volt measurement would show that two different phases were involved.)
For serious listening, I unplugged many electronic items not in the listening room such as all other stereo systems, my computer, and any item powered by a "wall wart" AC transformer; I also "de-tuned" all TV, satellite, and AM and FM radio receivers so that all that was received by these was random noise. Enid Lumley also made these suggestions all those years ago in her TAS writings.
One of the reasons I chose a basement listening room for my former home was to minimize RFI with the audio power and components. Putting as much of the wiring and audio space below ground level as possible cut down on radio frequencies in the audio space. The room's poured concrete walls also helped this goal. For example, per Enid Lumley's suggestion, I determined that an AM radio detuned to the bottom of the AM band produced mostly pink noise anywhere in my audio room, even near wiring. In contrast, in other areas of the house, bits of station programming in addition to hum, static, and cyclical loud noise products were audible from the AM radio even in the middle of a room, not only when placed along house wiring or next to electrical or appliances and electronics. This was well before my home or most homes used Wi-Fi and before the ubiquity of cell phones, much less smart phones. For many years I only ran FM signals into the audio room via shielded coax, not even routing wired satellite TV or cable signals into that space.
In 2010 my first wife of 34 years passed away unexpectedly. In 2015, my new wife and I moved into a new home in a different city. It was an existing older home, built in 1904. My music room by choice is now above ground with sunlight available through the window during the daytime. While I'd found that a dedicated audio electrical system is not a panacea, I viewed it as a worthwhile investment in an older home where the electrical system was largely an unknown. At least the electrical service had been upgraded to 200-amps with a modern circuit breaker panel during an earlier remodeling by the prior owner. Thus, one of the first home improvement projects we undertook was to install two dedicated circuits into the audio room. As before, this step, while not cheap to retrofit into an old plaster-walled house and not a panacea, is definitely worth the investment in terms of better sound quality.
[Continued below]