Any one measured the EMI/RFI attenuation performance of audiophile power conditioners?

@tvad Thanks for the reply. Just curious how did you measure the EMI/RFI? It's supposed to across the range o frequency, so did you use any sophisticated tool to measure it?

Also it's quite interestig that you did not hear any difference in your system after using the Cleansweep filter. Idealy one would expect some difference when EMI/RFI is removed from the power, so did you search for any answer as to why there was no chnage inspite of the product being very effective at doing what it's supposed to do?

Audio_phool

Of the technical reviews and test I have read, the filtering applies mostly to very high frequencies outside the audible band.  Keep in mind that the power supply inside the audio device should block or remove the EMI/RFI as it converts the AC signal to a DC signal.  That being said, I can hear our washing machine running through my AVR (but not my two channel system) and unless I am imagining it, I think my two channel system sounds better when there are no major appliances active.  I would think it would be possible to block everything but the 60 Hz signal with proper filtering, but there is probably a technical reason why it is difficult that is beyond my technical understanding.  

@12many As per your experience I can only conclude that a well built/designed electronic component will take care of all EMI/RFI, which is the case for your 2 Ch system. Since AVR are ussualy built with less care as compared to electronics for 2 ch, you are able to hear the EMI from Washing machine. As far as the DC is concerned theoretically there would be zero EMI on DC, but in reality some till gets transffered even to DC, thats the reason why in AVR you are able to hear the washing machine as all those electronic components work on DC. So in short we might be overreacting to the need of a power conditioning from the point of it's impact on SQ.

@tvad I had a look at the meter you mentioned, looks like pretty basic meter with not sure how it's arriving at the values (it must be averaging, but not sure how), still it's a meaurement which is better than no measurement at all.

Audio_phool

My experience with a TriField device is at the wall I may measure 395 and on the output side of my Puritan 156, I measure approx 95. So it indicates a 4x reduction in "noise".

@tvad though I have tech background, I don't want to purchase something for just couple of measurements, it will be waste money.

Looks like the trifield device is being used by many though I cannot exactly makeout how it's measuring and what to make out of it except some number increasing/decreasing

Audio_phool

Danish Audio group totally unique technologies in the $4-6k range 

3 well versed brands including Borrensen, AAvic ,And  the cable , line conditioner 

can’t recall the name begins with A , heard it vs the main stream brands and uses a bunch of active Tesla coils and other technologies to really lower the noise floor .

I am looking to buy one , the AAvic I280 integrated and line conditioner same group, is my go to hopefully later in the year , being married ,things don’t always flow as easy ,especially when you have a home and upkeep !!

Perhaps, if your power is very dirty, then you might be best to not use it. There is a current discussion on LiFePO4 batteries and pure sine wave inverters limping along on the Audiogon Forum.  Be warned, there is little forum interest in this topic and few with any experience.  I’m currently putting a system together based upon the rave review of my main go to guy on all two channel considerations.  Regarding conditioners, I use and can high recommend the Shunyata Everest 8000.  That said, getting off the grid has real appeal.

@tvad: Thank you for your kind words.  Indeed, we supply EMI filters for very broad applications around the world (including Antarctica).  Most of top U.S. universities (Caltech, MIT, U.C. Berkeley, and so on) use them in their R&D work.  Quantum computing here in the U.S. and in Japan use our filters to be able to work with very weak signals.  Nuclear power industry likes our filters too.  And, of course, various industrial applications.  If you don't meet or exceed published specification, you won't be in business for long...  Audio is a relatively small segment for our filters, just FYI.

Regarding impact on sound:  EMI filters (such as our CleanSweep) or any power conditioners are not supposed to affect sound in any way except to remove extraneous artifacts, otherwise they become a part of your sound path.  If you want to improve sound quality, then perhaps a filter shouldn't be your first choice...

Regarding measurements: people often make critical and/or expensive decisions based on measurements (think of a spot on a CT scan - was it caused by a spike on ground?).  Both tools and methodology must be considered and exercised carefully. If you are curious, here is a link to an article I wrote on the subject for inCompliance Magazine, a publication for EMC professionals.  Amazon-grade instruments aspire to provide "easy" and meaningful measurements, but you can get only that far on spirit alone without solid engineering foundation.  Their typical problems are insufficient bandwidth, lack of true peak measurements, and, importantly, missing common-mode measurements (i.e. between Live or Neutral to ground) - just to list a few.  This doesn't mean they are useless - any instrument, no matter how sophisticated, has limitations - just don't make surgery plans on that white spot on CT scan measured by Amazon...

Vladimir Kraz/OnFILTER

@vonhelmholtz Going off grid is better option, but that doesn't not answer my original question about measurements of power conditioning  products from Synergistic research, Shunyata etc. which given their price point, should be available from manufacturer himself. I'm not denying the improvements that you have heard with Everest 8000, but I read their patent on Noise Isolation Chamber and found that they are just running the power cables trough tubes filled with silica beads and/or mixed with Rochelle salt. So I'm very sceptical about the actual effectiveness of this method unless hard facts in the form of measurements are provided by the manufacturer.

@vk_onfilter thank you for taking time to reply. I agree to you that ideally power should not have any impt on the SQ, but if one has dirty power and it gets cleaned up then one should be able to hear the impact of it.

Regarding your point of measurements using Amazon grade instrument, while it's better than nothing but it does not really help in assessing the real life effectiveness and especially frequency spectrum where it is making any impact. It's like being in the middle of ocean and moving, you know you are moving but whether you armving in the right direction or not you don't get to know. To be more specific a lot of commercial products which are cheaply built ignore one of the main affect area of of around 100Khz which is caused by SMPS in LED and others, but if you use cheap device you won't know if it's really acting there.

Regards,

Audio_fool

@audio_phool

Give Shunyata a call and speak with Richard Rodgers. He is a valuable resource and can answer your technical questions.

Juan at @blisshifi can answer your questions regarding Synergistic Research power products and can most likely provide you with a contact at Synergistic Research.

@vonhelmholtz Sure I will communicate directly with Richard Rodgers. Hopefully they will be ready to share actual performance data.

Regards,

Audio_phool

@audioman58  The company you're thinking of is Ansuz.

@audio_phool , buy some test equipment and start testing.

Or you could watch what this guy measured or not.

https://youtu.be/GAxOMfiqiVg?si=b7LUnTqzegOrmJQi

EMI testing requires a Faraday cage.  The video with the FFT analyzer testing the effectiveness of a PC on an amp is fun to watch but keep in mind that this is a comparative test.  Like when we listen to a stereo component, we compare it to something else we have heard- be it live music or another component.  That is a subjective evaluation.  What this guy in the video is doing is also a subjective evaluation but with an analyzer.  Just because he has a computer outputting numbers does not make his comparison less subjective than someone doing a listening test.  Many people with highly developed listening skills can match or outperform measurement equipment.  Especially because we don’t always know what to measure or how to measure it.  The guy in the video could do the same tests again on a different day and get different results depending on the state of his power grid and local interference in his area.

An objective test must start with a baseline that is calibrated and repeatable.  That is why EMI testing requires a Faraday cage.  That is the EMI equivalent of an anechoic chamber.  That way even his test equipment is isolated from outside influence.  

I’m not knocking comparative testing.  We often have no choice and comparative listening is how we make purchasing decisions.  Item A sounds better to us than Item B and so we are satisfied with our purchasing decision until we hear something better.

I heard a difference in different PC’s and I hear a difference with and without one.  That is how I made my purchasing decision.  If I can’t trust my ears who can I trust?

@vonhelmholtz I had written to Shunyata as per your suggestion asking them for the measurements & below is the response related to measurements.

"We've published our own measurements on our up-market Everest and Denali power distributors that show a -68dB down at 1mHz noise measurement, which is top in the field.

The problem is that too many variables exist to definitively say this PC will make this system sound better in this way or another system will sound about the same with or without the PC.  These manufacturers are making a product that reduces line noise.  If it makes the audio system sound better, that's almost a side effect.  

Published measurement data of these PCs might be one way to show that they are working but how they affect the sound of an audio system is almost incidental.  For example, plugging an amp into one could make the amp sound worse because it limits current.  Measurements can only go so far.

Supposing you bought two different cakes from two different bakeries.  You take those cakes to a chemist and have him analyze them.  He gives you a list of ingredients and relative weight of each ingredient.  That analysis might give you some idea of the flavor of those cakes but until you take a bite, you will not know how they taste.  Furthermore, the chemist cannot tell you how each cake was mixed and baked- the process.  And the mixing/baking process could have a significant impact on the flavor.  

@tonywinga completely agree with you on the part that one cannot say what and howuch improvement one can hear from adding a power conditioner in your system as there are a lot of variables included. Since the only job of this piece is to decrease the EMI/RFI from the power line, it’s a completely objective parameter to measure and report which these audiophile companies are giving a complete miss, hence my original post.

Audio_phool

My first thought is manufacturers of PC’s prefer to keep their performance data proprietary as much as they can.  Why give their competitors easy access to performance data or also, it becomes a specification contest with no connection to sonic performance.  

I worked in Automotive where our products had to meet EMI/RFI emissions per the SAE and DIN specs.  I do not recall specifications or standards for devices that attenuate EMI/RFI.  Maybe I am wrong but that leaves noise conditioner designers to find their best design paths to meet performance or audio goals.  But without measurement or industry performance standards the claims and measurements of Power Conditioners with respect to we consumers could become very confusing.   It is already confusing for us because results vary between applications, local EMI noise conditions and how our unique audio systems respond to PCs.

I know, it's like talking about the weather.  I have the Niagara 5000.  It is also an obvious improvement for me.  Expensive and not as much fun as buying an amp, DAC or speakers but the improvement in sound is unmistakable for me.

@audio_phool 

I’m not well versed in power line noise and the resulting issues with a systems sound quality, but I thought that noise at 1Mhz was preferred to noise within the auditory frequencies and that such noise could be easily filtered.  Power conditioners and systems of conditioning like with Shunyata, or Audioquest claim to also limit noise generated by component such as switching power supplies.  So, I’m not clear on why filtering of 1 MHz signals is a key point of your post.

Audio consumers have complained for decades that power conditioner manufacturers don’t publish object measure of their products direct impact upon what we hear through our electronics.  Has anyone quantified what attributes must be measured and how they are measured?  I purchased the Everest and associated power cables on a ninety day trial and didn’t return it because it was the single greatest improvement that I had heard in my system to that point.  I recognize that this is subjective, but what group of measurements can be used to predict the listener’s subjective experience?

@tonywinga I don't understand whats in the performance data which needs to be kept secret even though the method of achieving the performance can be proprietary and hence method can be kept secret. In fact performance numbers are a thing to boast & if I was the mrketing head i will use them everywhere to market the product unless they are terrible & hence need to be kept secret.

Your example of Automotive industry exactly confirms the point which i said, except for the Audiophile industry, every other industry has standard norms and specs to be met, else the product is useless. In audio while sound is highly subjective and hence cannot be standardised the way it's done for other things, power conditioning or EMI reduction is something very well established & measurable thing, yet audiophile grade manufacturers of these products choose to ignore the specification and/or performance data.

@deep_333 I never said any of these products don't make the improvement/changes to the sound. My post was regarding lack of objective measurements/performance data for something which is completely objective. Will FDA accept a new drug if tomorrow the manufactrer will just say I saw improvement in a patient's condition?

Audio_phool

@vonhelmholtz I think you mis-read/interpreted my post. I was not highlighting the importance of noise reduction at 1Mhz, it was highlighted by Shunyata in response to my query about the performance data. They claimed that their Everest & Denali to have 68dB noise suppression at 1 MHz which is best in the field. But then I cited the example of $60 worth of filter from Schaffner to have Noise reduction of 70dB in common mode and 80dB in differential mode at 1MHz.
 

I am of the opinion that impact of power conditioning on SQ is dependent on various factors such as equipment, state of power, person's hearing etc. & hence can not be easily measured. But the performance of a power conditioner in terms of noise reduction is completely objective and measurable.

Audio_phool

@deep_333 I never said any of these products don’t make the improvement/changes to the sound. My post was regarding lack of objective measurements/performance data for something which is completely objective. Will FDA accept a new drug if tomorrow the manufactrer will just say I saw improvement in a patient’s condition?

Years ago, a group of engineers in a large manufacturing/test facility (defense/aerospace) were in deep sht with a certain kind of issue. The control system on some sensitive test equipment, one of a kind, one sole manufacturer in the world to meet specs, would freeze up due to some power anomalies that would occur in the midst of weeks long continual tests. Months of power monitoring with the most sensitive/most expensive equipment (that audio guys may have never even heard of) revealed that the monitoring equipment may not have been sensitive enough to catch weird sub-cycle spikes, etc or the ability to capture/characterize such anomalies in that industrial environment. There is nothing else to buy.

Solution: We isolated the control system on that equipment with some very expensive custom iso. transformers. The problem never re-occurred again.

If someone came back and asked me, "where oh where is the measurement/data trail that drove you to your grand solution?" All i could say is, "foff and don’t waste my time, the solution is in place!"...and that’s how it may work in certain types of industries at times.

FDA? Try and figure out all the complexities of the most sophisticated gadget in existence, i.e., the human body first..After that, we can talk about FDA and other crap (Most of your medication is apparently fixing one thing, breaking something else anyways).

Get a couple of engineering degrees, work in field for a few decades, start to get a feel for the limitations of what we can/can’t measure, how much we don’t freaking know in the grand scheme of things, etc, before you get really absolutist with some audio stuff. The internet read low info guys from the likes of ASR are the ones who feel mighty proud of themselves on a daily basis. They know everything there is to know apparently!

Another thought is that in order to publish performance data and avoid litigation, manufacturers must maintain a test lab’s certification and calibration and possibly have their test results certified by an independent laboratory.  That is not cheap.  It likely becomes a business decision of cost/benefit.  Unlike U-tubers who do their off the cuff tests with possibly uncalibrated/uncertified equipment.  At least I have not seen any of them publish their certifications in the footnotes or in their videos.  And furthermore, they should state that their data is for reference only.

Another thing about power conditioners that I found with regards to audio performance is that power cables still matter.  I bought my Niagara and Hurricane power cord and experienced a significant improvement in sound.  No question there.  My front end components are plugged into the PC, not my amps.  So I assumed that my good, not great power cords on my DAC and preamps were good enough.  After all, for this kind of money this PC should have been the end game- or so I used to think.  When I decided to try a higher level power cord on my DAC I was both surprised and disappointed at the improvement it made to the sound of the DAC.  This higher end power cord reduced the noise floor even more as well as making the DAC sound even better.  Now I had to upgrade the power cords on my preamps and the better power cords improved the sound.  So don’t expect the power conditioner alone to do it all for you.  

Deep_333, I know what you are saying.  We had some test equipment that has to measure in the 6 ma range.  These stands were decades old but suddenly we could not get a quiet enough signal to pass final test.  My theory was that the new solar farm less than a mile away was the culprit but I will never know.  My test engineer wanted ground rods sunk next to each test stand.  I had to have some long discussions with our facilities Engineering Manager to get his approval.  He was convinced it would be a waste of effort.  The stands were working fine before, blah blah blah.  Well, the ground rod worked.  They had to drill through the shop floor and then sink the ground rods while avoiding a 400 amp service trunk.  Yikes. 

@deep_333 Your example is a very poor one. Since you quoted that only one manufacturer existed, then obviously you had no other choice to find a workaround. So it doen’t apply to current situation as you have a neumerous manufacturers providing the product. Besides power for Audio isn’t anything really special either so don’t try to make it sound something very special. It’s attitude of audiophiles of accepting subjectivity in every thing under the sun has lead to manufacturers take advantage.

Besides even though I have technical lnowledge and come from research background I don’t think engineering degree is needed to understand the need of measurements for power conditioning products which cost and arm and leg. Just common sense is needed.

@tonywinga I doubt those certifications will cost so much that power conditioners costing tens of grands cannot cover it. Besides Im not going to get into cables, thats another debatable topic.

Audio_phool

@vk_onfilter I saw the productline of your company which looks impressive & you seem to serve diverse industries including chip manufacturing, R&D centers etc. and you have provided the performance chart for your products. Besides you seem to have more than 40 years of experience in the field of EMI/RFI reduction/compliance. Is application of EMI/RFI filtering to audio any special than other industries you serve which allows one to not to specify the performance data? Can such practice will be acceptable if the same product was to used in other industries than in Audio?

Audio_phool

@deep_333 Your example is a very poor one. Since you quoted that only one manufacturer existed, then obviously you had no other choice to find a workaround. So it doen’t apply to current situation as you have a neumerous manufacturers providing the product. Besides power for Audio isn’t anything really special either so don’t try to make it sound something very special. It’s attitude of audiophiles of accepting subjectivity in every thing under the sun has lead to manufacturers take advantage.

Besides even though I have technical lnowledge and come from research background I don’t think engineering degree is needed to understand the need of measurements for power conditioning products which cost and arm and leg. Just common sense is needed.

@tonywinga I doubt those certifications will cost so much that power conditioners costing tens of grands cannot cover it. Besides Im not going to get into cables, thats another debatable topic.

Audio_phool

Just pack your bags, start a thread at ASR and tell them what a measurement wiz/data driven technical genius you are. The A’gon guys and every manufacturer designing power conditioners for hifi applications (Michael Borresen, Garth Powell, etc) are all soaked in snake oil indeed. They can’t keep up with your unmatched genius.

Goodbye now

@deep_333 do youself a favor and get out of audio rabbit hole to see that even $10-$20 commodity grade EMI filters have the specs/data published. So if me insisting on specs/measurements is going to get you worked up so much; it's better for you to say goodbye. Else you have a job to keep these manufacturers alive in the audio industry, as they won't survive outside Audiophilia with this way.

Audio_phool

What will you do with the attenuation performance data of a power conditioner, if you ever get it?  Will you have the power coming into your home analyzed to determine the best fit power conditioner for your needs?  Is getting this performance information an academic exercise?  Or more importantly, are you concerned that a manufacture has significant product variation such that copies of the same power conditioner will affect the sound differently in your system?  Has anyone ever done such testing?  I know camera lenses can have significant variation among copies such that some people will order multiple copies of the same lens and keep the one they like best.  

Otherwise, published specs do not mean much to us (or is it we) end users except for application specific specs like amplifier power at 1, 2, 4, and 8 ohms or the input/output impedance of a preamp or amp.  A speaker manufacturer typically provides efficiency, frequency response measurement data and impedance curves but they do not provide information on the individual drivers used or the tolerances of the component values in their crossovers.  

Also interesting might be how much filtering amplifier and DAC manufacturers design into their products.  That is not typically listed in their specifications although some will tout their copper plated metal chassis construction or such; but still do not specify the difference it makes in noise rejection.  

To answer @Audio phool's question (sorry for a long reply - didn't have time to condense it):

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

QUESTION: "@vk_onfilter I saw the productline of your company which looks impressive & you seem to serve diverse industries including chip manufacturing, R&D centers etc. and you have provided the performance chart for your products. Besides you seem to have more than 40 years of experience in the field of EMI/RFI reduction/compliance. Is application of EMI/RFI filtering to audio any special than other industries you serve which allows one to not to specify the performance data? Can such practice will be acceptable if the same product was to used in other industries than in Audio?

Audio_phool"

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

The basic foundation of any technical product is a specification.  Engineering Bible starts with "In the beginning there was a specification" :)  In a number of ways a specification tells the designers of the products what a product should accomplish, in very specific terms (not "it should reduce noise a whole lot" but by how may dB at which frequency, and how it should be measured).  It tells the manufacturing group of the company that every single manufactured unit needs to meet or exceed very specific parameters (again, not just "sound good").  It is also a commitment that a supplier of a product gives to a customer - after all, the customer gives similar commitment to the supplier in a form of money.   Whenever you see a product that claims a whole lot but lacks that very specific commitment, it tells you quite a bit.  In the most benign case this would mean that a manufacturer has no idea what does this word "specification" actually mean - not a good notion for any product, especially a technical ones.  Anything else points to either knowing what that specification actually is and not being willing to present it to the customers; or thinking of a customer as an idiot who would buy anything "shiny" that is accompanied by flowery language and inflated price.  
In your own business, whatever it is, you likely buy and/or sell products and/or services.  Would you pay money in your business for something that has no "specification" of the sufficient type?  Would you feel right selling something where your customers have no idea what they are buying?

All our filters (of which AC EMI filters is just only one segment) have specification - sufficient to those in the industry who are in a need of noise reduction.  If we didn't have specifications and didn't stand behind it, truly, very few companies would even consider working with us.  From our perspective there isn't a difference between an EMI filter for a R&D center in a major university and the one for home audio - the only difference is so-call leakage current requirements to comply with the safety regulations - UL1283, UL/IEC 60939 (all our AC EMI filters are safety-certified by an independent accredited laboratory).  We have two basic kinds - industrial type, and hospital/medical/residential grade - grouped by the leakage current limits.

The sole purpose of a filter is to block to the best of its abilities incoming electrical noise and not affect in any adverse way the power itself.  Anything else is not a filter's job.  I believe it would be a mistake and an unreasonable expectation that somehow a filter (or a power conditioner) will improve sound quality, short of reducing incoming electrical noise.  Whatever quality problems you may be experiencing, don't start by adding a filter, unless all you need to reduce is noise.  Now, a poorly-designed filter/conditioner can add plenty of problems by itself, including intermodulation distortion, clipping, and so on - this is where a professional-grade product works, and the "shiny" ones may or may not.  

I do hear time to time from our customers in audio market that our filter either improved sound quality, or it didn't.  I would LOVE to know which specific parameters were affected - if only we knew it, the sky is the limit for the future improvements.  Studying for my MSEE specializing in audio I went through a good number of courses such as psychoacoustics, medical aspects of hearing, and alike.  I remember how at the conclusion of our course on Acoustics (a very demanding course because it is half-analytical and half-empirical) our professor said to the class "Now you know all that a man knows about sound, but only God knows what a man wants to hear" - that's sums it up.  I fully respect a huge subjectivity aspect of listening; I am also cognizant that if one buys an expensive "shiny" piece of equipment, one's brain works overtime to convince itself that it now sounds better for sure.

So, to conclude way-too-long of an essay, no, there is no difference for us in the filter design nor in requirements for the detailed specification for audio and for industrial or R&D market, short of safety regulations.

@tonywinga I am in the market searching for a power conditioner. So having the specifications and performance data will help me compare the options I have and make an informed decision.

I agree that speaker manufacturers do mot provide the data of individual drivers or electronics manufacturers do not provide info on the noise reduction incorporated. But for speaker manufacturer providing the specification of the entire speaker is more important than the individual one, hence specification of sensitivity, impedance & (in many cases) frequency response & in case of the electronics, they do provide the specification pertaining to the function of their product, e.g. if it's a pre-amp then they provide the gain & S/N ratio, impedances etc. Noise reduction is part of design which will mean how careful designer is to eliminate noises. Since thats not the primary function of that electronic they can skip on specifying how much reduction is achived through designing.

But in case of power conditioner it's main function is to reduce the EMI/Noise & manufacturers are omitting on specifying how well it's doing the job which it is supposed to do. Now imagine if Power amp, pre-amp or even DACs manufacturers stopped publishing all the specs? Isn't that problematic?

@vk_onfilter Thank you very much for the detailed reply. I appreciate your view on accepting both objectivity and subjectivity whereever applicable.
 

@deep_333 do read the response of vk_onfilter & let that sink in.

Audio_phool

Reference page 14 of the Niagara 5000 Owners Manual which can be found online.  That seems to list some of the noise reduction specs that you are seeking perhaps.

@tonywinga thanks for pointing it out. I wonder why they kept it in user manual where no prospective buyer is likely to look into. Though these are not exactly what I am looking for but better than not having anything.

Audio_phool

Want to point out that series mode power conditioners are essentially low pass filters that start working ~ 3 kHz. True for ZeroSurge and Furman with SMP while AFAIK, RFI filters usually start in the 10s of kilohertz. This is why I always recommend them for noise filtering efficiency.

Parallel filtration has a difficult time filtering out lower than that due to the limitations on caps across the hot and neutral. YMMV.

Also, keep your dirty power supplies (computer, cheap wall warts) out of the clean side of a power conditioner and use shielded power cables to ensure you don't suffer re-infection of noise after the power has been cleaned up. 

Actually, I study the owners manuals online of products I am considering purchasing.  My brother says the owners manual/assembly instructions are just one engineer’s opinion.  My brother breaks things a lot.

Otherwise if they publish the data then people can easily point out the issues with their asking price and actual performance.

@audio_phool you answered your own question. While data might be useful to customers, it will not be beneficial to the manufacturers unless they have top/best measurements. In fact, it’ll create more work (accumulating data, publishing data, answering data related questions) and likely loss of sales/revenue to do so. Also, many claim to “lower noise”, but it may not be exactly/simply the same as specifically “EMF/RFI” like you are interpreting

@tonywinga Thank you for pointing out the user manual part. Now I have created a table of values for EMI/RFI Noise reduction based on available/published spec. Took me some time to gather all info. But I think its a worthwhile exercise.

For any Power conditioner/Filter, it’s primary function is to reduce EMI/RFI noise on the mains line. Hence it’s objective performance is of high importance here. Now the performance of this noise filtering is evaluated based on the following parameters.

1. Noise reductionvalue:- The EMI Reduction value is expressed in the units of dB. Higher the value, better is the attenuation performance. Sometimes it’s also expressed as -ve dB value in that case lower the number better is the attenuation performance.
2. Frequency Range :- The performance of filter is not linear or constant over frequency range hence usually the graph of attenuation is plotted for range of frequency (Just like frequency response of speakers). For normal house hold scenario where noise is generated because of SMPS in LEDs, TV, fridges, washing machines etc, it’s frequency range usually lies around 100-150 KHz hence performance of any filter in this frequency range is crucial.

3. Mode :- EMI/RFI noise attenuation is measured in two modes Differntial Mode (DM) which is measured between live (hot) and neutral (cold) line (differential currents flow in opposite directions through the source and return path) and Common Mode (CM) which is about noise that flows in the same direction in a pair of lines (common mode currents flow in the same direction through the source and return path, completing the circuit through the ground path). Typically DM noise reduction values will be higher than CM mode values at a given frequency value & at the same load value. In both cases having higher values is desirable.
4. Load Values :- Typical Lab setting measurements are done with 50 ohms load and 50 ohms output impedance of power supply. These values often time look good (Schaffner publishes these lab values). But real world load and powerline impedances are anything but 50 ohms. Hence the realworld scenario would look like 0.1/100 where 0.1 ohm is the output impedance of powerline and 100 ohm is the load value or vice a versa 100/0.1. Schaffner removed the realworld performance data from their data sheets because it’s performance was worse in the area where it mattered the most viz. in 100Khz region.

Hence from above four points one can see what all needs to be looked at when looking for noise attenuation performance of any filter. So if any manufacturer specifies just a random number like PS audio for example, it doesn’t make any sense from the actual performance standpoint. Instead start asking for the hard facts based on these thingsfor the amount of money that we pay for these products.

@kennyc Yeah, now that you have pointed out, I can see that I had already answerd my own question. The table above puts hard facts around it.

Audio_phool

I am adding a separate column for frequency range specified/mentioned.

This will give a complete set of info which is as available on the product page/in manuals.

So as the anlysis of these figures availble, I can conclude that for most of the audiophile grade power conditioner manufacturer, the available specs are usless as they do not tell the whole story except for the Audioquest which tells specs only at Lab specs & not the real world scenarios.

Synergestic reseach is not publishing any spec at all even for their 28K unit which is criminal IMO. Considering the price of these units not disclosing the full specs can be considered very dubious. Whie Audioquest has discolsed their lab setting specs, they are sub-par and even $70 Schaffner filter has better noise reduction performance (which also specifies only lab condition vaues) which is the main function of all these units.

The only one to stand out of all these is EMI Filter by OnFilter, as they provide data for real world values instead of just Lab setting vaues & their performnce is very impressive indeed and that too at a lower price than all other audiophile counterparts.

Audio_phool

audio_phool

... I can conclude that for most of the audiophile grade power conditioner manufacturer, the available specs are usless ...

That's why it pays to test components in your own system.

Synergestic reseach is not publishing any spec at all even for their 28K unit which is criminal IMO.

Criminal? Really? Good luck to you as you try to warp the law to suit your opinions.

A note on input/output impedance: most measurements in RF domain are made in a 50 Ohms termination.  Conducted (i.e. on wires) EMC test per regulations is also conducted with 50 Ohms termination.  Appliance filters (this is the UL and IEC classification of the filters built into equipment to make it comply with EMC regulations) such as made by Schaffner and so many others are therefore optimized for 50 Ohms termination. One may say "tuned" for such termination for maximum attenuation. The problem is, I haven't met a power line of 50 Ohms yet.  More realistic matching impedance accepted in the industry is more like 0.1/100 or 1/100 Ohms, where the lower impedance is the source (i.e. your outlet) and the higher one - your load.
Some of the better appliance filter manufacturers like Schaffner (give it to the Swiss - they have specifications) and Schurter used to list in their datasheets performance at both 50 Ohms and 0.1/100 Ohms.  However, lately Schaffner has "sanitized" quite unfavorable data (I do have saved their datasheet from before the "cleansing") and for the most of their products they list only 50/50 Ohms data.  The only one I found which still has complete data is their FN343.   
Schurter still provides "honest" data for their filters - see this  as an example (you would need to figure your way on this page).

Scroll down and find the attenuation curves.  What you see is that 0.1/100 and 100/0.1 curves show "negative" attenuation at lower frequencies, meaning actual EMI amplification.  In short, in an EMC test lab this filter will help to comply with CE/FCC requirements; when plugged into real outlet - it will amplify noise. 

I wrote an article for inCompliance Magazine on the discrepancies between EMC regulations and the real world which, in part, addresses it.  

Look at the section called "50 Ohms Question"  You can find this and other articles in our online Technical Library

A corollary issue is the frequency range.  When you look at the above-mentioned Schaffner or Schurted data, note that the real-life attenuation curves end at 1MHz. There is a reason for that.  Parasitic capacitance and inductance of power cables essentially kills higher frequencies.  Now, what are the sources of the signals in a typical residential environment (for audio purposes)?  It is, in no particular order of significance, switched mode power supplies encompassing LED lighting, solar and other inverters, plug-in supplies for just about everything, TVs, and the list drums on.  Another source would be variable frequency drives (refrigerators, pumps, A/C, washers, dryers, etc.).  All of them operate at lower frequencies - SMPS, for example, work somewhere between 40kHz and 150kHz.  1MHz attenuation data that I see are not that relevant for real-life applications.

@cleeds not everyone has the option/luxury of trying all at home. So listening is not always the viable option. Why you want to defend these manufacturers for not providing specs is beyond me. Besides if you don't find anything wrong with zero specs for a power conditioner costing $28K then may God help you.

@vk_onfilter thank you for providing the real information and not something which these audiophile companies keep on blabbering.

Regards,

Audio_phool

audio_phool... not everyone has the option/luxury of trying all at home. So listening is not always the viable option ..

Many local dealers allow in home auditions. Many online dealers allow returns.

... if you don’t find anything wrong with zero specs for a power conditioner costing $28K then may God help you.

It’s not likely that an audiophile will spend $28K on anything without an audition first. You’re just being silly.

@cleeds  you don't get home audition from dealers all over the world. So that option is out of the question. So is the option of return from online dealers.

My system which retails north of USD 30K, I have bought it blind without any audition. So when you don't have option to try before  , you purchase blindly.

Lastly something like power conditioner whose performance cometely objective, you are fine to buy it without seeing any specs or being fine with lack of specs (even if it costs 28K) is funny in the first place. Will you do the same thing with sports car even if they didn't mention a single spec about engine, performance etc.?

Audio_phool

audio_phool

... you don’t get home audition from dealers all over the world. So that option is out of the question ...

It’s certainly true that some dealers do not offer home auditions. I’ve found that the "better" dealers - the ones who sell gear other than just mid-fi or mass market electronics - usually do provide the option.

Many online dealers advertise 30-day (or longer) trials. Brick-and-mortar dealers who offer this option don’t necessarily advertise it and it’s likely they won’t offer it to some nameless voice on the end of a phone. If you’re in the shop, it’s likely they’ll qualify you before offering the option. It’s that way with many high end sales. Home auditions are common, so simply stating "that option is out of the question" is plain silly.

My system which retails north of USD 30K, I have bought it blind without any audition.

I can’t imagine buying components that way but I hope it worked out for you.