Audioquest NIAGARA 3000 Power Demystified
Power Demystified
Garth Powell
2621 White Road Irvine CA 92614 USA Tel 949 585 0111 Fax 949 585 0333 www.audioquest.com
Contents
Introduction
AC Surge Suppression
AC Power Conditioners/LCR Filters
AC Regeneration
AC Isolation Transformers
DC Battery Isolation Devices with AC Inverters or AC Regeneration Amplifiers
AC UPS Battery Backup Devices
AC Voltage Regulators
DC Blocking Devices for AC Power
Harmonic Oscillators for AC Power
AC Resonance/Vibration Dampening
Power Correction for AC Power
Ground Noise Dissipation for AC Power
Appendix: Some Practical Matters to Bear in Mind
I. Source Component and Power Amplifier Current Draw
II. AC Polarity
III. Over-voltage and Under-voltage Conditions
Index
Introduction
The source that supplies nearly all of our electronic components is
alternating current (AC) power. For most, it is enough that they can rely
on a service tap from their power utility to supply the voltage and current our
audio-video (A/V) components require. In fact, in many parts of the world,
the supplied voltage is quite stable, and if the area is free of catastrophic
lightning strikes, there are seemingly no AC power problems at all.
Obviously, there are areas where AC voltage can both sag and surge
to levels well out of the optimum range, and others where electrical
storms can potentially damage sensitive electrical equipment. There
are many protection devices and AC power technologies that can address those dire circumstances, but too many fail to realize that there
is no place on Earth that is supplied adequate AC power for today’s
sensitive, high-resolution electronic components.
This is not to say these audio-video components will fail to run from
your utility’s supplied power, and, in fact, if you had not been exposed to
anything better, you might even believe they are performing and functioning well. However, with today’s alternating current, we’re relying on
technology that is over 100 years old, intended for incandescent light
bulbs and motors. The noise and radio frequency (RF) induced distortion that is present on every AC line—100-127 VAC / 60 Hertz (most of
the Americas, Japan, and Taiwan) or 220-250VAC / 50 Hertz (most of
the rest of the world)—couple with sensitive circuits in A/V components,
creating both distortion and low-level signal loss. In fact, via digital audio
difference file tests and spectrum analysis, it’s possible to measure up
to a third of low level (-70dBu, unweighted or below), signals are lost or
altered due to the preponderance of this ever-increasing noise.
In the following charts, you can see from the spectrum analysis, the
information you would lose without an effective AC power strategy.
Click the green icon and listen to the difference files below each
spectrum analysis chart. These are the native files u ncompensated
for volume. (Bernie Grundman Mastering audio was employed for
these tests – see index for details)
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• A typical AC wall outlet (A + A1 Inverted Phase)
The only detectable readings we see above are the self-noise of the
test equipment itself. It’s essentially zero.
This audio sample sounds like nothing because
it’s a sample and second inverted sample of the
studio’s wall power. No difference equals no
audio sample.
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• A well-regarded audiophile power conditioner/regenerator and
their premium AC power cable versus the wall outlet.
(A + B Inverted Phase)
( need text description)
Here we see a considerable difference. These AC power technologies are doing their job, and the signal you see and hear are those
that are lost to signal coupling and masking effects without use of
these AC power solutions.
What you hear is very low in level at times,
because you are hearing the difference. This is
the signal that would be lost without use of this
AC power conditioner and advanced AC cable.
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• The Niagara 7000 Low-Z Power Noise-Dissipation System and
Thunder AC power cord versus the wall outlet.
(A + C Inverted Phase)
Here we see a far greater signal difference. This is a more effective
AC power solution.
What you hear seems louder and fuller, because
the AC power technology can preserve far more
information. All audio files are native signal with
zero composition for volume level.
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These analysis charts are taken from the digital audio difference files
for all three test variables (the wall AC outlet A, phase inverted file
A1, and power products B, and C) figure 1. What’s significant about
this type of test versus the noise reduction over frequency (common
mode, ground, or differential mode), surge suppression, or distortion,
is that a difference file is the only one that perfectly tracks what the
product will do in a real-world audio system.
For example, we could take a sampling of 12 AC power products,
and test their noise reduction in a laboratory while feeding them signals from a signal generator at a fixed source and load impedance
(as is typically done). The problem is we can’t know exactly how that
will manifest itself in any audio playback system. There are simply
too many variables. In the same way, comparing the total harmonic
distortion of 12 audio power amplifiers and using that single test result as the only means of comparison would be utterly meaningless.
A digital difference file is unique in this regard. A 10-second sample
from a digital audio file is played through a chain of electronic components that convert digital to analog (as will always be required in
home playback of a digital source), and then it is converted back into
a digital signal and stored on a computer drive. This is done (in this
instance), with all of the system’s components powered from the AC
wall outlets, then powered via an audiophile-grade power regenerator/conditioner and their premium AC power cord, and finally the AudioQuest Niagara 7000 Low-Z Power Noise-Dissipation System with
our Thunder AC power cord.
Next, these digital signals are precisely aligned to the last sample,
beginnings and ends are cropped to start and end at precisely the
same time, and only then the first (control) digital audio file (A) is
matched start to finish with the A1, B, or C sample, one pair at a time.
Samples A1,B, or C are then reversed in polarity as compared with
their control file (A).
If the technology in the given AC power device and cable is not effective, or if the audio or digital component’s power supply is truly capable of eliminating enough RF and electrical noise so that the final
audio signals will be left pristine (unaltered), the result of this reverse
polarity “difference” should be zero. Nothing at all.
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Of course, what you see with any premium AC power device is a
sizeable difference, and with the Niagara Series products we see
even more. This difference is represented as signal. It’s not about
shaping the tonal color of the system or simply creating a mild euphonic effect, rather a substantial quantity of audio signal that will
either be lost or distorted from circuit-coupled noise. Low-level signals are critical to audio reproduction. They contain the majority of
instrument harmonics, the highest frequencies, the leading edge of
most transients, and nearly all of the imaging or spatial information.
These vulnerable signals will remain intact, only if the right AC power
technology is employed.
In fact, if you download this document from our website, you can
hear this for yourself. Bear in mind this is not a short audio clip
of glorious full-fidelity audio. Instead, you are listing to the difference
only. What you are hearing is the signal that would have been lost
forever without the aid of proper AC power regeneration, isolation,
or filtering tech-nology of some sort. The volume is the native
level, nothing was adjusted post production.
Beyond the signal loss and distortion that is due to the ever-present
and increasing noise on the AC line (industrial machinery,
satellite, short wave, AM/FM radio, cell towers, Bluetooth, and
harmonic noise from switch-mode computer power supplies), we
could also investi-gate the fundamentals of alternating current,
Ohm’s law, as well as transient voltage and current spikes that
can damage our sensitive components. However, these topics are
worthy of and would require a book rather than a short pamphlet).
So, for this installment, I will primarily devote the following pages to
a discussion of how various AC power technologies can affect
sound quality. Although the basics of alternating current are well
covered in numerous engineering articles and books, the way in
which many AC noise and power phenomena affect the audio signal
has never been especially well documented.
When examining these phenomena, it’s important to understand
that any honest assessment of electrical circuits and their
implementa-tion will be fraught with compromise. The key to
designing any AC
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power delivery device that will serve a system best is knowing the intended application. It would be unwise to assume that the AC power
technology most appropriate for a factory or broadcast facility is also
ideally suited for a home audio system. Additionally, engineering with
circuit-design dogma is rarely productive (everything has its place
and nearly every idea has some merit). What’s important is to strike
the best overall balance between the various appropriate AC power
technologies, while neither omitting any critical design aspects nor
focusing too much attention on only a few positive attributes.
Detailed below are some of the dominant AC power technologies
used in and outside of our audiophile and A/V industry. I will attempt
to explain their basic working technology, their strengths and weaknesses, and how they will affect a high-resolution audio system.
AC Surge Suppression
The technology associated with AC surge protection was originally
meant to provide a minimal level of protection against catastrophic damage caused by AC voltage and current spikes. The protection circuit or
devices must be adequate to handle up to 6000 volts peak and 3000amp transient current spikes. Any level of power beyond that will not make
it to your system without your building catching on fire and your breaker box
and electrical wiring turning to molten steel, copper, and plastic.
The primary concern is usually either an electrical storm or a damaged
utility power transformer. If the spike is not too severe, it can be absorbed and turned into heat by various means. The most common and
affordable are metal oxide varistors (MOVs). Some circuits employ avalanche diodes, gas discharge tubes, or active switching detector circuits
with line induction and switching transistor relays (SCRs).
There are two basic types of AC protection devices: sacrificial and nonsacrificial. Ideally, the purpose of the sacrificial protection circuit is to
absorb enough of the AC voltage or current spike to save the connected
components and their power supplies from catastrophic damage. At
times, the spike could be so severe that the protection circuit will be
damaged and “give its life” to either save or minimize the damage to the
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connected components (thus, it is sacrificial). These devices are quite
useful in areas where electrical storms are common and the resulting
damage to electronic devices is well known.
Unfortunately, some of these devices do not give a reliable indication of
having been either damaged or destroyed after one or more extreme
power spikes. Further, if the power event is not a fast transient, but a
sustained surge that persists for minutes or hours, most of these circuits
will not only give their lives, but they will then pass the damaging voltage to the power supplies of the connected components. Sadly, many
otherwise premium AC filter-conditioner-regenerators rely on a variant
of this low-cost sacrificial power surge/spike technology.
The other less common power surge/spike technology is non-sacrificial
or non-sacrificial hybrids. In some circles (particularly pro audio/sound
reinforcement), the specifics of these circuits are highly contested, and
considering that the application can be so vulnerable, given outdoor
events with considerable exposure, expense, and risk, it’s understandable that there’s contention about which circuit clamps spikes faster, at
the lowest voltage above RMS, and with the least damage to its own
circuit devices. However, as its name suggests, the whole point of nonsacrificial surge/spike protection is to protect the connected components
without sustaining any damage to itself. That, along with the ability to do
so in the intended application, is what’s paramount.
This technology always requires a passive/active circuit, because
voltage detection of some type is necessary, and it must react in a
fraction of a second to be effective. For example, if a multiphase electrical service, such as those found in every office in
the world (typically three-phase wiring), were to lose its neutral,
and a portion of a system is connected to at least two AC service
outlets from a different phase, then the AC outlet group that draws
the least current will suffer a huge voltage surge. Only an overvoltage shutdown cir-cuit can protect against this, and only a nonsacrificial surge circuit can survive.
Catastrophic failure is only one concern, however. It’s important to
understand that our electrical grid is and always has been optimized
for simple appliances. Many audio components feature robust tran-
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