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

@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