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Impact of AC Distortion & Noise on Audio Equipment

solderdude

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Tests done in an EMC lab with the correct equipment/circumstances and acc. to specific norms (FCC or CE) for household appliances.
All the 'mock-ups' one can make are not controlled, are incorrectly coupled and may exceed allowable or practical levels.

When one is bothered by weird sounds one needs to rule out step by step what is causing it. I see no reason to test where a specific devices in a specific circumstance reacts with unknown levels of God knows what frequency spectrum.

I have dimmers in my house (still on filament bulbs) some cheap LED lamps (some cheap Chinese ones create more crap than any dimmer could) have a few phones, have wifi and have never been bothered by weird sounds. As it should.
 

b4nt

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It will be more about the whole circuit in my family room....My dimmer light is wall mounted light, can't be taken out separately to connect to the power cord. I will be turning on my AV setup and light when doing my tests.

: )

It won't hurt, just add (within the max wattage limit of your rolled of mower cord), if you connect also your capture laptop on that power cord, so on. What you will add should add a minimal amount of noises on your cord.

What you will do won't be very clear and scientific. But you should get a not so clean environment, at no costs.
 

b4nt

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Tests done in an EMC lab with the correct equipment/circumstances and acc. to specific norms (FCC or CE) for household appliances.
All the 'mock-ups' one can make are not controlled, are incorrectly coupled and may exceed allowable or practical levels.

When one is bothered by weird sounds one needs to rule out step by step what is causing it. I see no reason to test where a specific devices in a specific circumstance reacts with unknown levels of God knows what frequency spectrum.

Thanks :)
 

Wes

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where do you want the RF signal to be induced to the DAC or pre-amp? Over its interconnects? Somewhere else?


Either the most susceptible point, or the point that audiophiles think is most susceptible... same for other questions.
 

b4nt

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Either the most susceptible point, or the point that audiophiles think is most susceptible... same for other questions.

To deal with that, I added a 20dB attenuator beween my DAC and my amp. So my DAC output level must be higher, for a better SNR.

Since, my 4G phone can be on my desk, and I do no more get noises from it in my audio.

Alternate option: keep your phone away.
 

MrPeabody

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I skimmed through the first 17 pages of this thread, reading maybe half of the posts.

I often find that it is helpful to start by applying some simple logic to the question, and to allow the logic to drive the investigation.

Here, the following seems appropriate:

In order for an external power conditioner to improve the SQ of an amplifier or other audio component, the two following statements must both be true:

1. Distortion routinely exists on the mains, which many typical audio components on their own cannot deal with effectively.
2. External power conditioning is able to correct the problem by presenting the audio component with a more perfect mains power supply.

The proper way to conduct this investigation is to start by performing a thorough study of the distortions that are routinely encountered on the mains. Once that has been done, the next step would be to study the capability of typical home audio components to deal with the kinds of distortions that are routinely encountered. After those first two steps have been done properly, it is indicated to undertake a study of the capabilities of individual, external power conditioners.

That's mainly what I wanted to say. But I also want to point out something that I do not think has been made adequately clear, at least not in the first 17 pages of the thread.

The power supply filter in any audio component is tasked to filter out all AC leaving a pure DC signal. The nature of any filter that can do this is such that the higher the frequency of the noise or distortion component, the more effective the filtering will be. It follows directly that assuming that the frequency components of noise and distortion are weaker in amplitude than the fundamental (60 Hz or 50Hz), that if there remains an audible artifact in the audio output of the component, the artifact will be ripple at the fundamental mains frequency (60 Hz or 120 Hz, or 50 Hz or 100 Hz). It follows directly that, with that same assumption, for any audio component with a power supply filter that is adequate to suppress the ripple to a level below the threshold of audibility, noise and distortion on the mains is not a concern. In other words, for any audio component that is capable of adequate suppression of the fundamental mains frequency, the only possible way that an external power conditioner can be beneficial (other than surge suppression) is the case where the frequency components of noise and distortion on the mains are stronger in amplitude than the fundamental mains frequency.

If perchance there is consensus that the preceding paragraph is correct, then it would seem obvious that the investigation, of the question of whether external power conditioners are useful for more than surge protection, reduces almost entirely to the question of how common it is for frequency components of noise and distortion on power mains to be stronger in amplitude than the fundamental. It seems to me that this is what this big question reduces to. Maybe someone has provided information of this sort in the remaining 18 pages that I haven't yet read. I suppose I'm going to have to read the rest of it.
 

MrPeabody

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Great post and video. Now the big question is... Does PS Audios Power Regenerators, the P15 or P20 PowerPlant have any impact? Because I believe that produces the absolute cleanest power you can get.

You could say, where do we stop, but if the PS Audio P20 Powerplant has no effect then I'm 100% on-board with this idea that they have zero effect.

I'm not in the disbelief camp, it's been proven that this has no effect. But, I'd like to see if 100% regenerated power, completely clean power has zero effect of what we hear.

The problem with the claims of Paul at PS Audio is that implicitly he claims that the power regenerator is helpful to ALL audio systems regardless of the quality of the power supply in the audio components and regardless (especially) of the noise and distortion present on the mains. As such he is selling snake oil even if it happens that the gear he is selling is actually helpful in specific cases where the mains power is highly distorted that you would barely be able to recognize the waveform as a 60 Hz (or 50 Hz) waveform. It is impossible to rule out the possibility of these kinds of cases. It probably exists somewhere. But even allowing that it does, it is not honest to promote the idea that mains power is distorted to such a great degree routinely, everywhere. Again, Paul implicitly claims that all audio systems will benefit from power regeneration, which is to say, he claims in effect that no matter where you live, and no matter the quality of the power supplies in your gear, his power regenerators will improve the sound quality of your system. Even though this is manifestly hogwash, lots of people have fallen for it and swear that they can hear the difference. Several people have responded to this thread saying as much, i.e., that they hear the difference the power regenerator makes, and that they do so irrespective of any knowledge of the cleanliness of the mains or of the capabilities of the power supplies in their audio gear.
 

audio2design

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Tests done in an EMC lab with the correct equipment/circumstances and acc. to specific norms (FCC or CE) for household appliances.
All the 'mock-ups' one can make are not controlled, are incorrectly coupled and may exceed allowable or practical levels.

FCC does not care about susceptibility. CE does not test to any level of detail w.r.t. audiophile standards for susceptibility.
 

solderdude

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CISPR 14-1 (or EN 5504-1) is defining the emission requirements for household appliances, electric tools and similar apparatus. CISPR 14-2 (EN 55014-2) is defining the immunity requirements for the products which are under this standard.

Of course there is no immunity testing for audiophiles but there is for household appliances which home audio falls under.
 

b4nt

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1. Distortion routinely exists on the mains, which many typical audio components on their own cannot deal with effectively.
2. External power conditioning is able to correct the problem by presenting the audio component with a more perfect mains power supply.

Can you list 3 such recent typical audio equipments?

In other words, for any audio component that is capable of adequate suppression of the fundamental mains frequency, the only possible way that an external power conditioner can be beneficial (other than surge suppression) is the case where the frequency components of noise and distortion on the mains are stronger in amplitude than the fundamental mains frequency.

In which situation would one see a harmonic stonger than the main 50/60Hz fundamental?

We may have found sources of free energy, if in such, we filter out the fundamental.
 

b4nt

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FCC does not care about susceptibility. CE does not test to any level of detail w.r.t. audiophile standards for susceptibility.

Of course there is no immunity testing for audiophiles but there is for household appliances which home audio falls under.

Audio equipments are specific compared to a boiler. Their performances are more or less described by vendors, they can be heared if they are bad, and can be measured. You get or not hum from PSU, you get or not distortion, you have a known SNR, a noise floor.

Did you ever see an audio equipment spec section describing its "mains immunity"? Why don't we see such specs?

The only point I could see for some amps is cap sizes present in PSU, but advertised so for bass.
 

b4nt

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I now found this. Source could be serious. Sorry for your necks.

https://www.emcstandards.co.uk/files/61000-4-13_immunity_to_ac_supply_distorted_waveforms.pdf

What Amir lastly ran with 90° was a test with sort of huge notching distortion:

SomeExamples.PNG
 

MrPeabody

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Can you list 3 such recent typical audio equipments?

In which situation would one see a harmonic stonger than the main 50/60Hz fundamental?
We may have found sources of free energy, if in such, we filter out the fundamental.

I am a little bit puzzled by this. I'm not certain, but I think you may have misinterpreted what I wrote. You quoted the two numbered statements that I had written, but you left out the sentence that immediately preceded the two numbered statements. Here is a quote of the same two numbered statements that I had written, but with that preceding sentence included:

In order for an external power conditioner to improve the SQ of an amplifier or other audio component, the two following statements must both be true:

1. Distortion routinely exists on the mains, which many typical audio components on their own cannot deal with effectively.
2. External power conditioning is able to correct the problem by presenting the audio component with a more perfect mains power supply.

While I'm not certain, I suspect that you may have misinterpreted the two numbered statements as absolute assertions of sorts. The fact that you left out the critical preceding sentence in your quote suggests to me that this is what you did. If so, please realize that what I said is that those two statements need to be true in order that an external power conditioner can possibly improve the sound quality of an amplifier. In other words, something like: "In order for A to be true, B must be true," where the two numbered statements are the B.

That last sentence of yours is a puzzle. This sentence: "We may have found sources of free energy, if in such, we filter out the fundamental." I have no idea what you mean by this, and I cannot fathom any possible way that it relates in any particular way to what I had written.
 
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MrPeabody

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I now found this. Source could be serious. Sorry for your necks.

https://www.emcstandards.co.uk/files/61000-4-13_immunity_to_ac_supply_distorted_waveforms.pdf

What Amir lastly ran with 90° was a test with sort of huge notching distortion:

View attachment 147458

Interesting. I would point out, though, that no one has suggested here (to the best of my recollection) that THD is a useful metric for the quality of the mains supply. More to the point, there is no implication or suggestion, in Amir's use of distortion in the demonstration he performed, that THD should be a useful metric for this purpose. He used distortion in a way that was very appropriate and very useful for doing what he actually did, i.e., for showing that the DC power suppllies in the three components were perfectly capable of dealing with the distorted AC supply all on their own, without any assistance from an external power conditioner/regenerator. Hopefully, no one would have interpreted this as any sort of suggestion that THD should be a useful metric for the quality of the mains supply.
 

b4nt

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Interesting. I would point out, though, that no one has suggested here (to the best of my recollection) that THD is a useful metric for the quality of the mains supply. More to the point, there is no implication or suggestion, in Amir's use of distortion in the demonstration he performed, that THD should be a useful metric for this purpose. He used distortion in a way that was very appropriate and very useful for doing what he actually did, i.e., for showing that the DC power suppllies in the three components were perfectly capable of dealing with the distorted AC supply all on their own, without any assistance from an external power conditioner/regenerator. Hopefully, no one would have interpreted this as any sort of suggestion that THD should be a useful metric for the quality of the mains supply.

Amir did distortion measurements, using 1kHz, and plotting by the way how a noise conditionner can improve the values: "nada", he wrote.

He did this first with a 35° dimmer shape, many complained. He since added a 90° dimmer test. No diff.

@pma here added one shall care also about mains IM distortion caused by PSU/PSR....

@pma have a look at that doc, really interesting: https://www.emcstandards.co.uk/files/61000-4-13_immunity_to_ac_supply_distorted_waveforms.pdf
 

Pdxwayne

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@b4nt , if you have free time to check files, go ahead and play with them, I have done some captures yesterday.

Note that no amp was involved.

In the same circuit, TV, AVR, Sub, light with dimmer, and a fan were turned on.

Devices under test:
Node2i (Coax out), Topping E30, Topping L30, Focusrite Forte, and laptop for using Reaper to capture.

Plugged to wall
Vs
Plugged to Furman Elite 15 Power Factor i. It is just a conditioner and not a generator.

The files null well together. Clock drift seems again slightly more for wall powered chain. Null results seem slightly better for Furman chain.

Against the orig, left null worse than right. It seems Furman left channel (capture 1) did several dB better than wall plugged capture1.

I already spent hour got the things setup, captures, and done a bit of comparisons. But there are still too much to compare....


Here are the captured files with orig:

https://wetransfer.com/downloads/aa...f866f6db573ab5c7baa565c120210814170320/e270cb
 
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MrPeabody

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Amir did distortion measurements, using 1kHz, and plotting by the way how a noise conditionner can improve the values: "nada", he wrote.

He did this first with a 35° dimmer shape, many complained. He since added a 90° dimmer test. No diff.

@pma here added one shall care also about mains IM distortion caused by PSU/PSR....

@pma have a look at that doc, really interesting: https://www.emcstandards.co.uk/files/61000-4-13_immunity_to_ac_supply_distorted_waveforms.pdf

And what's your point? That the events that you've identified constitute assertions that THD is a useful metric for the quality of the mains supply? Is there some reason why you are reluctant to say this plainly? Here, I'll do it for you ... "These various events that I have (you have) identified are all logically equivalent to assertions that THD is a useful metric for the quality of the mains supply." This seems a very bizarre statement to me, but it is undeniably what you are asserting. It is nearly as disingenuous as when you misquoted me, omitting the context for those two statements that I had written. When I responded to that I went to some effort to gave you the benefit of the doubt, but I now think that you probably realized that you were misquoting me but didn't care.
 

b4nt

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@Pdxwayne Topping E30, Topping L30

You do not describe how they are powered up.

> Furman Elite 15 Power Factor i
Seems this is mainly an EMI/RF filter (-40db from 10kHz, -80dB from 100kHz). Plus additionnal surges protections.

If I would have very expensive audio stuff, I may buy such a conditionner, hoping he would burn on lightnings, and save so the remaining.

> Here are the captured files with orig
From here, this links to a single file only
 

Pdxwayne

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@Pdxwayne Topping E30, Topping L30

You do not describe how they are powered up.

> Furman Elite 15 Power Factor i
Seems this is mainly an EMI/RF filter (-40db from 10kHz, -80dB from 100kHz). Plus additionnal surges protections.

If I would have very expensive audio stuff, I may buy such a conditionner, hoping he would burn on lightnings, and save so the remaining.

> Here are the captured files with orig
From here, this links to a single file only
e30 using phone USB charger. L30 using it's own power supply.

Yup, I got the Furman mostly to protect my expensive setups, for it's form factor, and it's ability to provide temporary extra power.

Strange. I clicked on the link a few times, each time I saw 9 files to download.
 

b4nt

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And what's your point? That the events that you've identified constitute assertions that THD is a useful metric for the quality of the mains supply? Is there some reason why you are reluctant to say this plainly? Here, I'll do it for you ... "These various events that I have (you have) identified are all logically equivalent to assertions that THD is a useful metric for the quality of the mains supply." This seems a very bizarre statement to me, but it is undeniably what you are asserting. It is nearly as disingenuous as when you misquoted me, omitting the context for those two statements that I had written. When I responded to that I went to some effort to gave you the benefit of the doubt, but I now think that you probably realized that you were misquoting me but didn't care.

I may have miss understood what you wrote, adding "no one has suggested here (to the best of my recollection) that THD is a useful metric for the quality of the mains supply".

I didn't omit anything in #696 where just that part is in bold. you added also: "Hopefully, no one would have interpreted this as any sort of suggestion that THD should be a useful metric for the quality of the mains supply."

This is what pma added some time ago, a TDH plot:

pmaInput.PNG
 
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