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Power Conditioner Audio [Does It Improve Sound Quality?]

Power conditioner audio

What is a power conditioner in audio? What does an audio power conditioner do?

A power conditioner is a device, that cleans its input AC energy with some quality (waveform, noise and/or distortion level).

The conditioner has no single definition and may include one or several types of functionality:

  • voltage stabilizers;
  • surge protectors;
  • uninterrupted power sources (UPS);
  • electrical suppliers with sine output;
  • filters and others.
Power conditioner explained

Of course, when we adjust the power supply and audio unit connection, we should remember proper grounding and cable shielding (including ferrite ring applications). Because it is also a very important aspect of hum/noise suppression at outputs of audio equipment. Only all these measures together provide an effective way of sound quality improvement.


Voltage stabilizer

Input voltage value may vary over time (unstable). As example, it happens due to load re-distribution in a power network.

A voltage stabilizer support output value in the allowable range about 110 or 220 Volt to protect a supplied equipment against damage.

When the input value is outside the extremal range, the stabilizer turns off output energy.

Voltage stabilizer
Voltage stabilizer


Surge protector

Due to commutation processes in a power network, voltage pulses have risen. It is significantly shorter variations, comparing the instability, that solved by voltage stabilizer.

Surge protector filters these pulses at own output. But it doesn't compensate slow changes, like the stabilizer.

Surge protector
Surge protector


Uninterrupted power sources (UPS)

Power network energy may disappear due to different reasons. Uninterrupted power source contains accumulator, that charged by input energy. When it's broken, the accumulator feed inverter module, that converts DC from the accumulator to high voltage AC at the output.

When the accumulator is discharged, UPS is turned off. It can automatically send a message to special software at a supplied computer to finish work. Also, UPS gives a sound signal, that notifies a human, that it is necessary to shut down the computer manually.

Some UPS may work up to several hours. As rule, external accumulators are there.

Other uninterrupted power systems keep energy supply until the start of a petrol generator's engine. These systems have lesser accumulator capacity, comparing ones noted above.

The time of accumulator work depends on UPS load. Read more in F.A.Q.


An uninterrupted power source (UPS)
Uninterrupted power source (UPS)


Filters and others

Many UPS and stabilizers, pass-thru input voltage value to output without changes, when input value in the allowable range.

When input value out of the range, the output voltage may be replaced to synthesized one. The waveform of the synthesized voltage may be non-sine (example: square). Some power conditioners may synthesize the sine waveform. Such units, as rule, have a higher price.

Power line wires receive radio and other sources of interference. Their products can come to the power input of an audio apparatus. Some conditioners filter these products. Practically, in many cases, these products are filtered into power supply units of the audio devices.

Power purifier / filter /
Power purifier (filter)


When several devices with high-frequency (HF) sources are connected in a single energy-system circuit, each of the devices can "share" own HF interference to other equipment via cables as wires and/or as antennas. Filters, based on ferrite rings, convert a radio-frequency electromagnetic field to warmth and rid the cables against the interference.


Read frequently asked questions and more details below.



Frequently asked questions

Does a power conditioner improve sound quality?

The conditioner may impact (depend on implementation) to interference level and, sometimes, the voltage into energy wires inside a supplied audio apparatus.

But, as rule audio appliances have an inner power supply unit, that stabilizes voltage and filter noise from its input. And conditioner filtering does not matter.

Read details...


Is a power conditioner worth it? Do I need a power conditioner?

If your home AC energy system is low qualitative (high level of voltage deviation), a conditioner with stabilizing ability is very necessary.

Also, high voltage peaks may cause audio equipment damage. Some conditioners may truncate these peaks.

Short and unexpected energy supply breaks also can cause equipment damage. Uninterrupted energy ability can protect the apparatus.

Read more details...

Is power conditioner worth it


Is a power conditioner the same as a surge protector?

Surge protector tries to suppress high voltage peaks. It can break the AC circuit when peak too long and/or too high.

A power conditioner has many definitions. Depend on implementation, the conditioner may work as surge protection.

Read more details...


What is the best power conditioner?

Best power conditioner provides at the output:

  • minimal-distortion-and-noise sinusoidal signal with
  • voltage and frequency according to local electrical requirements.

However, its actual impact to sound quality depends on your equipment, quality of AC-energy system and shielding, grounding of the apparatus.

Read more details...

What is the best power conditioner


What is a line stabilizer conditioner?

Line stabilizer provides output AC voltage value in a defined range. If the input value is too high or low, the stabilizer turns off output supplying. The appliance may be combined with surge protector and uninterrupted energy supply. The algorithm of the work of the stabilizer depends on its implementation.

Read details...


Does power conditioner eliminate hum?

A conditioner may be capable to filter interference at its own AC output line. But supplied audio appliance contains own energy supply unit, that provides such filtering. As rule, the unit successfully solves the hum issue.

Read details...


What is the difference between a power conditioner and UPS?

A UPS (uninterrupted power supply) primarily provide output energy when the input supply disappear.

But, practically, UPS may include the conditioner functionality:

  • voltage stabilizing,
  • surge protection,
  • etc.

Read details...


How do I clean my AC power?

The author recommends primarily use:

Also, some supplied audio equipment may be sensitive to waveform/distortions of energy-supply voltage. And sine waveform of the conditioning-unit output may be desirable in this case.

Necessity and degree of power purification may be defined by the manual of the audio apparatus or estimated by measurements.


How do I clean my AC power?


What does 1000VA mean on a UPS?

VA (Volt * Amper) is a measurement unit of complex electrical power.

It defines electrical load at the output of the uninterrupted power source.

Maybe you heard about W (Watt) unit. It is an active power.

The active power of a 1000VA UPS is lesser than that value.

Example: If your audio device marked as 1000W then you need UPS, which supports more 1000W. Such an uninterrupted power source always provides complex power more 1000VA.


Why is using UPS recommended? Do I really need UPS? Is UPS worth it?

Uninterrupted power source protect supplied equipment against damage due to electrical voltage deviations. There are several kinds of protections.

If your electrical energy supply is proper and has no interruptions, UPS is no need. As example, your building supplied by own safe power station, that:

  • stabilize voltage,
  • have reserve energy supply and
  • other.

If you supplied apparatus is very critical to unexpected AC supplying off (data losses at server or desktop computer, as example), UPS is mandatory.

Read details...


How big a UPS do I need?

An autonomous time  of work of uninterrupted power source (T, s or second) depends on load (L, W or Watt) and accumulator capacity (C, Ah or Amper*hours).

T = C / (L/U) * K.

K is coefficient, that accounts the losses in the UPS. It always lesser 1.0.

If the power of an UPS (VA) in VA, L(Watt) = VA * cos(θ).

Where cos(θ) (cosinus of θ) is value defines active power. The value may be noted in UPS documentation.

As rule, UPS manual contains an approximate time of work for different loads.

The time may be expanded when a UPS allows connecting of additional accumulators (including external ones). Some units may use an automotive accumulator.

Read about UPS...

Is UPS worth it


What is HIFI power filter?

As rule, hifi power filter is device that filter noise and, sometimes, voltage pulses in a power network. The author is not sure that noise suppressing is actual for feeding of power supply unit of an audio device. But, pulse suppressing may prevent damage of the equipment.

The author recommend use voltage stabilizer to easier work conditions and defence of the audio setup against damage.

Of course, remember, that actual necessity in noise filter is studied practical way primarily via ears and/or measurements.


What is the difference between a power conditioner and a surge protector?

A surge protector is one kind of power conditioner.


Do power conditioners save energy?

No. A power conditioner causes energy losses in own electrical circuits.


How do I get clean power for audio?

Primarily, power cleaning is matter of inner power supply unit of an audio unit. To aid, we can add power conditioner at AC supply input of the unit.



Do power conditioners work for audio?

At least, a power conditioner may works as supply protector of an audio device against damage.


Noise reduction at an analog output of the device requires engineer approach with control of the conditioner actual effect.



Do surge protectors filter power?

A surge protector suppress (filter) short pulses of power voltage. It may be done with gas discharging tube (plasma surger aresters), in instance. The surging may be combined with high frequency filtering.



AC - alternating current

DC - direct current

PSU - power supply unit

PWC - power conditioner

UPS - uninterrupted power source


Why do I need a power conditioner?


What does power conditioning results look like?

Pure sine 50 or 60 Hz is a reference waveform of alternating (AC) electrical current.


  • distortions and ambient interference are added to the sine when the current spread thru wires via:
    • air or
    • power network connections;
  • transformers, electrical motors and other equipment generate pulses in switching modes.

Such "dirty" AC from an electrical outlet feeds home or studio audio apparatus.

Power conditioner (PWC) eliminates (in some approach) the pulses, distortions, noise entering from an energy supply network. The conditioner may reduce average-voltage variations in time due to the commutation of supplied equipment. Read the overview of the conditioning functionality...

Conditioning of an electrical power

Electrical power conditioning


At the drawing

  • waveforms and
  • its spectrums

(theoretical, before and after power conditioner) are shown.

Red lines are different types of harmonical distortions. A conditioner suppresses these distortions. Some conditioners may synthesize sine voltage.

These plots are not real and demonstrate the principle. The harmonic level depends on the input waveform and the conditioner abilities.


Power supply and sounds quality

If power supply filtering, shielding, grounding is bad, it causes many different kinds of hum. It may be checked at higher volume knob positions during the listening of a recording silence or stopped playback.

If electrical energy supply doesn't keep voltage level for increase (or a sharp increasing in short-term) of electrical load, it can cause non-linear distortions (the author would call it "dirty sound"). The technical details read below.

Here we mean DC low voltage of energy supply, that directly feeds audio circuits.


Sound quality is noise and distortion level at an analog output of a musical device.

Noise from wires can penetrate to an audio output:

  • add noise and/or
  • modulate a musical signal.

Below we'll study an audio system structure to better understanding how it works.

Power conditioner sound quality


Power quality and digital audio

Bad power quality may cause errors in digital data circuits. It can cause distortions of an analog signal, that converted from the digital data.

Commutations in digital circuits can cause interference in energy supply wires and impact on analog and digital circuits.

Also, read about jitter issues...


How to connect and use a power conditioner

A power conditioner (PWC) is connected to an electrical network outlet.

At an output outlet of the PWC, alternating current is filtered (sine purifying). The current feeds heterogeneous home or musical equipment, including studio ones.


Power conditioner abilities (depend on implementation)

Power conditioner abilities


  • An automatic voltage regulator (stabilizer) is the very recommended ability for audio and studio equipment. It may be sensitive to deviations of voltage.
  • A pulse protector defends an audio apparatus against overvoltage pulses.
  • A noise filter removes different air (caught on wires) and other interferences.
  • An isolation transformer implements galvanic isolation to electrical noise suppression. The transformer break so-called ground loops [1], causing additional currents in an energy line. Theoretically, the transformer (as a coil) may improve surge suppressing.
  • Remover of a constant component of the input voltage. The component causes additional heating of electrical transformers into a power supply unit of an audio device.


There is no standard definition of "power conditioner" term.

Various devices, from the simplest pulse protector to complex multifunctional one, may be considered as a power conditioner.

Since conditioners may have different functionality, you need to check its specification mandatorily.


Audio equipment should be connected to output outlets of the conditioner. Connect grounding according to the conditioner's documentation.


Noise spreading into an audio apparatus

Noise spreads 2 ways:

  • electrical energy supply wires,
  • air.

The wires conduct more interference than radiation through the air.

Spreading ways of electrical noise

Spreading ways of electrical noise



How power conditioning works


In the simplest system, the power conditioner feeds a single device.


Power conditioned system

Power conditioned system


From the AC-energy line, "dirty" electrical voltage feeds the conditioner.

Over-voltage pulses are suppressed by the surge protector. It allows protecting against the audio-device damage.

The auto voltage regulator keeps long-term voltage changes in the given range at the output of the conditioner unit.

The noise filter suppresses high-frequency harmonics.

In the extremal case (too high or extremely low voltage), the conditioner can break the input-line connection. It protects the audio appliance and the conditioner against damage.

Some conditioners are capable synthesize a sine at the output.

However, often UPS output waveform is square.

The conditioner unit may have an internal accumulator battery (UPS functionality). In the extremal case, the unit may switch the audio device feed to DC/AC converter, that fed by the accumulator[2].


UPS design types

Example of design of switched uninterrupted power source

Example of design of switched uninterrupted power source


Alternatively, the DC/AC converter can feed an audio apparatus permanently.


Example of design of UPS with a permanent generation of AC-voltage

Example of design of UPS with permanent generation of AC-voltage


Only some models of conditioners provide sine voltage at output outlets. Carefully read the unit specification and manual.


Noise spreading through a power supply system

Noise and voltage variations of external energy network pass through a power conditioner with some reducing.

Noise spreading thru a power conditioning apparatus

Noise spreading thru power conditioning apparatus


Power supply unit (PSU) inside the audio device, transforms high-voltage alternating current to low-voltage direct one.

Noise partially passes through the power supply unit and penetrate to low-voltage DC-line.

The unit generates own interference. Thus, external noise (from AC input) and own PSU's hum should be considered separately.

Further, the cumulative noise comes to analog and digital parts through the internal DC energy buses. Also, the digital part generates own interference.

The analog part under a musical signal also affects to the low-voltage line. Because active element (transistor or tube) switching change currency and, respectively, voltage into electrical energy bus, that feeds the part.


  • Therefore, the energy supply system is a comprehensive thing with several interference sources and feedbacks.
  • Total noise in low-voltage energy lines (including penetrated external AC interference and variations) affects the audio output.
  • To estimate power quality, we should check the interference spectrum and level at the analog output of audio equipment.



How to estimate power conditioner

To estimate the quality of a power conditioner unit, we can compare interference at the analog output with and without the unit.

If the difference is invisible, we can use the unit as a surge protector.

Measurement of the conditioner impact to sound quality (noise level)

Measurement of power conditioner impact to sound quality (noise level)


In general, the functionality of a power supply unit of audio device is the same conditioner:

  • surge protection,
  • high-frequency noise filtering,
  • automatic voltage regulation.

Other hand, a conditioner may:

  • provide a wider AC voltage range,
  • be better as a surge protector.

It means, that the conditioner may be capable provide better conditions for the power supply unit of an audio apparatus.


The conditioner abilities may be estimated via power-line noise meter. It plugs into home and conditioner outlets and displays both noise values. If the conditioner works properly, interference at the conditioner outlet should be lesser, then at home one.


Estimation with the power-line noise meter


  • Noise suppression at AC input of the audio device is not the final aim.
  • The final aim is sound quality increasing (noise at the analog output of an audio appliance by AC energy source).


So we should check the interference level at analog output first.

After it, we can learn the spectrum of energy lines before PSU of an audio device.


To reduce the interaction of analog device parts through the low-voltage energy buses, line isolating filters are applied.


Power system structure with noise-isolating filters

Power system structure with noise isolating filters


The filters reduce AC part of the bus voltage and reduce the penetration of the AC part to the analog output of the device and between the parts.


How to choose the best power conditioner for audiophile equipment

First, you should define for yourself:

  1. Do you want the best power quality before AC-input of audio equipment? or
  2. Do you want to minimize the impact of the quality to sound quality in your speakers or headphones?
  3. Do you want to protect your apparatus against damage by energy network deviations?

Case #1 is purely abstract and does not refer to sound quality.

Case #2 is an actual issue, that solved via power filtering, grounding and other measures.

Case #3 may be solved more simply and cheaply, than case #2.

Above we have considered how to check the real impact of the conditioner to the audio appliance.
It is a comparison of noise and harmonics at the analog-output spectrum of the audio system with and without the conditioner.

Also, we can check it for different kinds of test audio signals to check the conditioner under dynamic load (altering the conditioner-output load during a time).

There are maybe cases:

  • No difference;
  • Altering of noise and artifact level.

If a conditioner doesn't provide the difference, it does not matter that conditioner you use.

When conditioners cause different interference levels at the analog output of feed appliance, conditioner with lower noise/harmonic level is preferable.

To be exact, we can correct the noise/artifact measurement result according to the ear's frequency-sensitivity curve. But your ears may have the curve form different from averaged one.

The simplest way is ear checking of interference at higher volume knob positions during the listening of a recording silence (zero level) or stopped playback.

Power conditioner comparison
Power conditioner comparison


Let's compare:
the analog output of the audio device A, that is connected to conditioner #1,
the analog output of the audio device A, that is connected to conditioner #2.

The audio output of device A
Power conditioner comparison for device A

For ideal power filtering, we should view the only useful signal and the noise floor at the spectrum of analog output of a device A.

When device A is connected to conditioner #1, we can observe some harmonics, with unknown genesis, above the floor.

When device A is connected to conditioner #2, we can observe these or other harmonics, above the floor, but with a lesser level.


So, we can suggest, that conditioner #2 is more appropriate for device A.


Now let's compare:
the analog output of other audio device B, that is connected to conditioner #1,
the analog output of audio device B, that is connected to conditioner #2.

The audio output of device B
Power conditioner comparison for device B

When device B is connected to conditioner #1, all harmonics below the floor.

When device B is connected to conditioner #2, all harmonics below the floor too.


So, we can suggest, that no difference between conditioners #1 and #2 for device B.


Batteries vs AC power supply units

There is an opinion, that batteries can fully solve hum and interference issues, unlike AC power supply units (PSU).


  1. Batteries may require frequent replacement for the charging procedure.
  2. Qualitative PSU's filter and other measures solve the hum/interference issue successfully.
  3. Despite the unit have air interferences, the air is not so significant path of the interference as spread via wires, that solved in goal 2.
Batteries vs AC PSU
Batteries vs AC PSU

It is not necessarily fully suppress hum in energy wires into an audio appliance. If no measurable artefacts at the analog output of the device, such a filtering level is enough. And it does not matter batteries or AC PSU are there.


When you can't measure a spectrum, you can compare the audibility of noise/hum components at a high volume level for both batterie and AC-adaptor feedings.
WARNING: be careful, accidental playback start, any switchings or other signal rising at high volume can damage ears. Set minimal loudness when doing any switching and others.


Dedicated power lines for musical apparatus

Somebodies try to solve issues of sound quality improvements via dedicated power lines.

If the line is just wires, there is no sense to do it.

WARNING: Any kinds of power-network applications and works require special knowledge. All these works should be performed by professionals.


Electric tension stability

Primarily, the author would recommend providing stable electric tension.

If your home is fed a three-phase electric line, you should distribute the load evenly between these phases.

Dedicated power lines
Dedicated power lines

Practically, heterogeneous home equipment has a significant load and periodically switched. As example: electrical oven, refrigerator, etc.

It causes load re-distribution. And each of the phases may have different tension. The more load difference the more pressure contrast.

If your equipment is sensitive to the variations, the stabilizer should be used as a source of the dedicated line.

As rule, an audio apparatus is not a big load. And a single-phase connection is recommended.

WARNING: Multiphase connection is sophisticated and may require a special approach to avoid different kinds of damage.


Surge protection

Surge protection is recommended with and without the stabilizing.


Noise filtering

As rule, high-frequency filtering is not a big matter. Check its necessity this way.



  1. Sound quality is defined as noise and distortions at the analog output of audio equipment.
  2. "Clean" AC, coming to an audio system, is not target on its own.
  3. A single way to estimate the impact of AC power quality to sound quality is interference measurement at the analog output of the audio device or system.
  4. Both, power supply unit of an audio appliance and the conditioner, have the same functionality.
  5. But power conditioner may have a wider allowable range of AC parameter deviation and provide better conditions (keeping proper electrical mode, surge protection) for the PSU.
  6. Practical "home" way to check a conditioner effectivity is check noise/hum at high amplifier volume when playback is stopped.
    WARNING: be careful, accidental playback start, any switchings or other signal rising at high volume can damage ears. Set minimal loudness when doing any switching and others.



October 12, 2021 updated  | since July 2017


  1. Bill Whitlock. Understanding, finding, & eliminating ground loops
  2. High-Availability Power Systems, Part I: UPS Internal Topology



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