[TF1216]

Let no noise go unsilenced



If you think of mains power as the ‘gasoline’ fuelling your audio system, the AC iPurifier is the product that ensures that it’s getting a clean, super premium blend to deliver the best possible audio fidelity.

The AC iPurifier is the latest in iFi audio’s stable of ‘power products’ designed to clean-up noisy mains supplies to audio systems. But this is no ordinary mains purifier. Technologically advanced, it’s Active Noise Cancellation (ANC) circuitry can eliminate far more noise across the frequency range than other passive devices. At -40dB, the difference is as distinct as night and day.

The following diagram depicts the placement of three AC iPurifiers in one system.

• Insert AC iPurifier (1) into the shared mains wall outlet.
• Place AC iPurifier (2) at the first entry point.
• A third AC iPurifier (3) is best located in-between the two types of power supplies.

We recommend that all linear power supplies are located after the AC iPurifier (2) but before AC iPurifier (3). Then all SMPS power supplies are located after AC iPurifier (3).

Also, the digital and analogue power sources should be in their respective groups as shown in the diagram.



Specifications:

• Noise Reduction: >40dB (> 100x) at frequencies over 1 MHz
  > 20dB at 100 kHz
• Surge Protection: max. 30,000A @ 1,000V/10uS
• Operating Voltage: 90V – 265V
• Size/Weight:

(USA) 40mm x 105mm (L)
108 (g) / 0.24 (lbs)
(EU) 40mm x 115mm (L)
126 (g) / 0.28 (lbs)
The retail price of the AC iPurifier is US$99 (ex-tax) or €109 /£99 (incl. tax).

Next in line are AC iPurifier technical notes, hence stay tuned!

[ExileSt]

Sounds brilliant, but I'm particularly curious about the surge protection.  That it can put a full stop on power to devices it isn't plugged in to is a little tough for me to get my head around but that aside, as practical questions:  Is it rated, in terms of joules, amps and whatnot?  Does it need to be reset after it's tripped?  (And does one of these mean I can get rid of my horrible, but necessary, Tripplite Isobar?)

And just in terms of general operation, you've got a diagram showing how one can deploy three iPurifiers.  Would just one be effective for, say, a dac, an iTube2 (love it!), a power amp, and a sub -- 4 devices?  Which of the 6 features you list on the product page most benefit from using multiple iPurifiers?

[TF1216]

Surge Protection: max. 30,000A @ 1,000V/10uS 
This will mean lightning strike or similar. It will auto reset after a strike - say after few mins.

One AC iPurifier is fine for decent mains.  If the mains are noisy then additional ones would be helpful in the order as we have suggested.

Digital supplies and analogue supplies best grouped as per the diagram. 

[mikeeastman]

Do you have a trial period return policy? I've spend $100s on devices to fix my power and not one has worked.

[Speedskater]

Specifications:
    Noise Reduction: >40dB (> 100x)

That's an incomplete noise specification.

[TF1216]

AC iPurifier
Part 1/5: Actively goes where no purifier has gone before



Mains is the fuel that powers an audio system. Whether it is clean or not has a material impact upon quality and the user’s enjoyment of playback. iFi’s latest ‘power product’, the AC iPurifier, is no ordinary mains purification commodity.

Technologically advanced, it is an ACTIVE not a passive product, so it goes above and beyond and cancels far more noise across the frequency range than passive devices.

They are, in effect, flip sides of the same coin and are the bane of audio systems regardless of the type of power supply.

It is effective against both:

• Common mode noise existing equally on both of the power pins, referenced to the earth pin.
• Differential noise existing only between the two power pins – the net to earth is zero.

Nullifies noise others can’t reach

Compared to other generic noise filters, the AC iPurifier is superior because it is ACTIVE as opposed to passive. This enables it to achieve a far more comprehensive termination of noise across the frequency spectrum. As noise exists across the frequency range, this clearly means the AC iPurifier is unparalleled when it comes to neutralizing noise.

This chart compares the AC iPurifier (green line) which is ACTIVE to generic mains filters   (red line) which are typically passive.





The effective noise reduction difference is as different as night and day.

• MUCH better at up to -40dB and…
• Effective across a wide frequency range, compared to passive filters which cover only very high RF frequencies.

Every audio system benefits from the AC iPurifier

The AC iPurifier is designed for use in ANY mains powered audio system and is very effective when added to modern audio systems that have an abundance of digital and analogue components. Typically these systems are powered from a plethora of mains plugs. All of these ‘wall warts’ can add their own unwanted noise issues and pollute the local mains supply. However, the design of the AC iPurifier is such that it is even more effective if several are used to ‘contain’ the same type of noisy sources.

Insert it into the AC mains wall outlet supplying the audio system OR insert into the mains extension block powering the audio system. Try both locations to determine which has the greatest impact on improving any noise issues.



Bristling with serious Power Technology

Compared to similar AC power products, the AC iPurifier can boast the technological features below, making it far more comprehensive and effective than its rivals.



Stay tuned, there's more!

[HAL]

In the first post the wording for where to put each type of equipment is the opposite of the diagram shown. 

Should the analog equipment go after 2 and digital equipment go after 3 as in the text or diagram?

[AndrewA]

Very interested in these.

Though I note that the form factor is pretty similar to some other products, e.g. Shunyata Venom Defender, or High Fidelity MC-0.5.

Is the technology inside completely different?

[TF1216]

Specifications:
    Noise Reduction: >40dB (> 100x)

That's an incomplete noise specification.

Good catch.  The noise specs have been updated.

[TF1216]

First, we need to assure everyone that no snakes were hurt in the making of the iPurifier AC and no snake oil is contained in the product, the only oil in the production chain is crude oil that provides the basics for the plastics used.



Is there a scientific basis for the function of the device? Certainly and we can measure significant attenuation of noise on our 2.5GHz RF spectrum analyser between the AC iPurifier inserted and removed.

Indeed using additional plug in capacitors to filter HF noise is not exactly new and tends to be fairly effective at higher radio frequencies. However both practicality and safety agency requirements mean the values of these capacitors have to be fairly low and their effect is thus limited to higher frequencies, often > 1MHz.

In modern EMC (electro-magnetic compatibility) testing, typically frequencies below 150kHz are not included and frequencies below 500kHz allow relaxed levels of noise emission.

So many power supplies (even linear ones) release fairly large levels of noise in these frequency bands while passing all EMC standards. And it is often these lower RF noise components that cause trouble in audio systems and that are not easily filtered inside of audio gear either (no matter how diligent the designer is).

Going active allows us to address especially this < 500kHz noise rather effectively. This way the AC iPurifier achieves very wide bandwidth compared to simple passive capacitor based plug in devices.



Our ANC uses a simple analogue forward circuit, which is very fast and is backed by and hands over to capacitor based passive filtering for high frequencies. So there is no "noise echo" or any such problem.

Where the active circuit is fast enough to provide the opposing noise it kills noise, where it becomes too slow passive filtering through capacitors takes over.

The use of active noise suppression in mains powered systems is not exactly new, it has been used in large scale industrial applications for a while. It's application in domestic power systems to reduce mains born noise at frequencies much lower than possible using passive means and specifically to improve audio systems.

===========================

A single AC iPurifier is fine to use and provides significant objective noise reduction. More than one unit in use increases the noise reduction in our measured tests more than the expected simple doubling/tripling etc. and provides wider bandwidth of noise suppression as well.

Further, as any noise has to "pass by" the AC iPurifier placing it between "noisy" devices and "noise sensitive" devices improves the situation more for noise sensitive devices than placing it at the beginning or end of a power extender strip.

==============================

A note on the surge suppressor. These devices are in parallel with the mains, they are not resettable circuit breakers - instead their function is to limit any voltage between live/neutral by drawing extra current.



This current drawn to limit the voltage to safe levels may very well trip conventional current based circuit breakers, but the MOV is NOT a circuit breaker in itself. It also needs no re-set, if the surge is over it simply stops drawing current to limit the voltage.

===============================

[TF1216]

AC iPurifier
Part 2/5: Mains noise. A real bane.

Power supply noise is the bane of every audio system. There are always multiple sources of noise and they come from two main sources – inside and outside.

External noise is all around

This chart shows that noise is anywhere and everywhere and some of it inevitably ends up in the mains that supplies the audio system, due to the mains wiring acting as aerial. Most of the sources, we can do little about as they are found in everyday life such as radios or mobile phones.



The next chart shows the ‘local’ noise sources found in and around an audio system.


Local noise comes from hi-fi components

These sources of noise are found in hi-fi systems and come from three main sources:

• AC mains power supplies
• Switch-Mode Power Supplies
• Digital circuitry.

From left to right:

• The first set of noise sources (10k > 10MHz) relate to AC supply rectifiers and their harmonics caused by Linear Power Supplies (LPS). Yes, they make a noise!
• The second set of noise sources (67k > 200 MHz) is caused by Switch-Mode Power Supplies (SMPS). By comparison, these harmonics run in the higher frequencies.
• The third set of noise sources (8 MHz > 500 MHz) is caused by digital circuitry, clocks and their harmonics. And this type of noise exists in the most upper frequencies.
• You can see from the chart that the concentration of noise is from 30kHz upwards (the lower the dB, the less influential is the noise).

LPS vs SMPS

It is worth noting that, as much as LPS designs get a good reputation and SMPS designs get a bad reputation, the re
[​IMG]ality is somewhere in between. And the situation is dynami
c.



First, LPS designs are on the whole, good and, on average, are quieter than poorly designed SMPS power supplies (which tend to be more for charging mobile phones and are not optimised for noise). This is why LPS is often perceived as superior to SMPS.

Hybrid and electric cars used to be shunned, yet they are now all the rage. We believe the same is happening for SMPS. These are now more environmentally-friendly and consume far less power. Whereas all SMPS used to be ‘noisy’, we are one of the few companies who have broken down the SMPS into its constituent parts and fundamentally re-designed it for audiophile use ie super low-noise. The iPOWER is the ‘Model 3’ of SMPS power supplies.

Nevertheless not everyone has an iPOWER at their disposal. It is therefore important to be able to effectively deal with normal SMPS noise which can be quite severe.

The next section explains which aspects of the AC iPurifier target the different groups of noise and how this compares to the common approach.

Stay tuned, there's more!

[TF1216]

In the first post the wording for where to put each type of equipment is the opposite of the diagram shown. 

Should the analog equipment go after 2 and digital equipment go after 3 as in the text or diagram?

Shouldn't make much difference. Most important is that they (analog/digital) are grouped together.

[TF1216]

AC iPurifier
Part 3/5: Active beats passive.

Passive filtration is the most common approach seen in aftermarket power supply accessories.

However, it is not without its limitations:

• It filters only in the very high frequencies in the high MHz region.
• To be effective, the capacitors must be large and this means bulky and costly.

Given these drawbacks, the AC iPurifier had to be different, more thorough and more comprehensive.

The solution for the AC IPurifier is active + passive sections for the most complete purification over the frequency range.

1. Active Noise Cancellation (ANC) - covers high KHz and low MHz ranges
2. Passive Noise Reduction (PNR) - covers the high MHz range
3. Intelligent Earth - connects to devices without earth to drain mains leakage noise to earth

The chart below illustrates the impact upon noise.



The black line represents normal noise found in a system with no remedy for it. It runs across the frequency range at 0dB as it is not reduced.

The red line represents typical mains accessories that have passive circuitry – these typically start to work at around 1 MHz.

The green line represents the AC iPurifier impact by starting at 10k and then reducing noise by up to 40dB all the way up to 100 Mhz! By comparison passive filtration starts much higher in the frequency range at 1 MHz so misses out on filtering two-thirds of the noise.

AC iPurifier against generic passive filters

As explained earlier, external sources of noise, from radios to TVs to mobile phones, are not concentrated in just one area as they contribute to noise across the frequency range.

The graph below shows how the AC iPurifier nullifies external noise sources across the frequency spectrum.

By comparison, the generic passive filter does not deal with certain radios and walkie-talkie type products.



With local sources of noise, these range from linear power supplies (yes they make noise!) to switch-mode power supplies to digital circuitry and all the related harmonics.

It should be no surprise that, with the AC iPurifier actively covering the frequency range, far more noise is reduced – by an impressive -45dB or so!

By comparison, with a generic passive filter, noise from linear power supplies and switched-mode power supplies remain with only some digital circuitry being attended to.

[TF1216]

AC iPurifier
Part 4/5: Where to deploy.

The AC iPurifier works by taking out noise across the frequency range. In terms of effectiveness, it typically reduces noise by up to 100x or 40dB (and sometimes more).

The following diagram shows the placement of three AC iPurifiers in one system.

• The first AC iPurifier (1) is best located in-between the two types of power supplies. For example we recommend that all linear power supplies are located after the second AC iPurifier but before the third. All SMPS power supplies should then be located after the third AC iPurifier.
  

• A second AC iPurifier (2) should then be situated at the first entry point of the wall mains into the extension block.

• A third AC iPurifier (3) is best inserted into the shared mains wall outlet that supplies the downstream audio system.

By connecting this way, all the respective noise is ‘contained’ and terminated in its immediate vicinity. Also, the digital and analogue power sources should be in their respective groups as shown in the above diagram.

[TF1216]

Very interested in these.

Though I note that the form factor is pretty similar to some other products, e.g. Shunyata Venom Defender, or High Fidelity MC-0.5.

Is the technology inside completely different?

Our AC iPurifier was designed and build differently than those fellas. It uses our proprietary ANC technology and serves as a useful diagnostic tool.

We don't like to comment on other manufacturers' products especially when I don't know how their stuff works. 
I am a big fan of Shunyata's stuff though.  I suspect their device works rather remoarkably.

[Tomy2Tone]

Is this available yet? If so, can you point to me where it can be purchased? Thanks!

[TF1216]

Is this available yet? If so, can you point to me where it can be purchased? Thanks!

It is.  Music Direct is one spot where they can be purchased inside the States.

[AndrewA]

I got one of these and after a couple of hours plugged in, the flat end (where the green lights are) is pretty darned warm.  Is this normal?

(BTW, when plugged in, the letter and lights on the end aren't perfectly horizontal.  Again, is that normal?)

[HAL]

Sounds the same as mine looking at it and temp wise.

[TF1216]

I got one of these and after a couple of hours plugged in, the flat end (where the green lights are) is pretty darned warm.  Is this normal?

(BTW, when plugged in, the letter and lights on the end aren't perfectly horizontal.  Again, is that normal?)

Yes, this is normal.  It is an active device with a certain amount of power consumption so heat is produced.

And yes...this is normal.