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Impact of AC Distortion & Noise on Audio Equipment

Blumlein 88

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Yes, the post you are pointing to, is digging the hole deeper. It doesn't show what you claim it does.
 

b4nt

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Yes, the post you are pointing to, is digging the hole deeper. It doesn't show what you claim it does.

Discussion was longuer. Ask @solderdude

OutputStageBW.PNG
 

b4nt

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@amirm This will be my last input here. Main problem with Internet: missundestandings. Now I'll wait and read only, and see if the experts here converge at some point, and propose more than dimmer at 90°, more than EMC/CE abnormal mains shapes, for "audiophile grade" certifications.
 

audio2design

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You really have trouble reading and understanding things do you ?

Lacks knowledge to understand ....


Rohs Complian ... Yup totally believable. Oh FCC marking requirements have changed you don't just put the FCC logo if there is space.
 

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solderdude

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It was public on around july 4th: https://www.audiosciencereview.com/...-khadas-tone-board-1.24596/page-9#post-836011

Now we are in August. Ok, I'll hide that episod.

Again... here you did not understand what I wrote or didn't want to understand or thought I did not understand.

EMC testings and standards propose common worst mains abnormal shapes/disturbances.

No they state how to do certain tests and what to test and to which levels at certain defined circumstances. And not just mains related.

I tested a lot of firmwares of DLAMs and xDLS modems. This being mostly analog/modulated, over copper. Some where buggy (wrong rates, bad SNR, CRC errors, unexpected resynchs...), this was solved by vendors before deployments. Towards millions of DSL lines and modems.

Yes, usually one doesn't market things when all known bugs are fixed. Haven't you ever wondered why nearly all digital devices can and need to be updated ?

An operator once conmplained, cause many (several tenth of thousands) of his users didn't get at all the quality one could expect from DSL. The operator expected firmware fixes. All issues where solved by fixing cablings, either in end users homes, or in the operator's copper plant.
That's exactly what I explained in post #776
Besides several tenths of thousands is several hundreds ;)

I ask again:
I'll reply again: see post post #776

Now I'll wait and read only, and see if the experts here converge at some point, and propose more than dimmer at 90°, more than EMC/CE abnormal mains shapes, for "audiophile grade" certifications

Since you appear to know so much about audiophile grade certifications, EMC, mains shapes why don't you setup a draft about what to test, describe how the tests are done and what signals and levels are required so you can certify 'audiophile grade' performance.
Do you reckon Amir also has to check radiated emission and build himself a screamingly expensive RF isolated an-echoic room including the needed equipment? Is that also needed for audiophile grade performance as seen in the picture you found on the web ?
 

audio2design

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Cheers, expert.



Edit haha, Google!

https://fcc.report/FCC-ID/2AZ6U-EX5/

Dude again grow up!

You just posted a FCC intentional emitter test report that only covers the ISM band(s). That is actually not enough on its own for compliance. You still need to be able to prove compliance for unintentional emitters from 30MHz - 1GHz and technically better have on hand a conducted emissions test with a recommended AC supply.

I actually have used the same test lab as Topping it turns out. Small world.
 

b4nt

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I dropped a mail to admins, via web, to get my account definitively locked. Or is there a procedure for this?

and build himself a screamingly expensive RF isolated an-echoic room including the needed equipment?

Yes, one isolated room for each equipment, and we'll do the same at home, to reach audiophile quality :)

Dude again grow up!

You just posted a FCC intentional emitter test report that only covers the ISM band(s). That is actually not enough

For the full test reports, you will need to contact Topping.

25of75.PNG
 

JohnYang1997

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Lacks knowledge to understand ....


Rohs Complian ... Yup totally believable. Oh FCC marking requirements have changed you don't just put the FCC logo if there is space.
I have already addressed this before. It's only the prototype we sent to Wolf. All retail units don't have any issues including the one sent to Amir.
 

MrPeabody

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@MrPeabody Amir made the choice to plot TDH measurements, I assume he knows what he did. pma mentionned that that way, he could identify harmonics due to PSU poor PSR. More noise from PSU side, not able to filter mains noises out, this might cause effects in audio stages.

I just asked @Pdxwayne if he could also plot 32 tones, to see. For what difference we could see in harmonics, in the bottom sides on such plots:

View attachment 147488


@b4nt, when you include graphs and articles, when writing responses to what other people have written, you need to try much harder to make certain that the other person actually did say something that is refuted by the graphs and articles. Moreover, when you misquote another person, the misquote is a misquote no matter if it occurs through omission of critical pieces of what the other person had written, especially when it is manifest that the pieces you omitted are absolutely critical to the correct interpretation of the part you quoted. Your defense of the misquote reveals a basic lack of sincerity, which fact is the only reason I am now bothering to draw attention to it again.

... I didn't omit anything in #696 where just that part is in bold. ..."
View attachment 147484

I had written this: "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:" Immediately following that statement, I gave the two conditions on which improvement of the SQ, by an external power conditioner, is inherently predicated. The two conditions are that (1.) Distortion routinely exists on the mains, sufficient in severity such that typical audio components are not able to deal with it, and (2.) The external power conditioner is able to correct the problem by presenting the audio components with an undistorted or less distorted AC mains. These two conditions are the necessary and sufficient conditions by which an external power conditional may be beneficial.

In your response (it was the only one that anyone wrote), you did not question whether the two conditions I identified are the necessary and sufficient conditions. Instead, your response treated those two conditions as claims I was making. This is exceedingly, patently bizarre. In essence you asked me to defend those two conditions as though I had claimed that they are true conditions. It makes no sense at all, for you to have interpreted what I wrote in the manner that you did. As such, it is difficult for me to seriously regard anything that you have to say.

I was very much impressed with Amir's demonstration. Yet, as always, several people objected. One person in particular objected excessively and boorishly. His principal objection was that distortion in the AC voltage matters only if it occurs at the voltage peaks such that there is an affect on current output from the power supply, unaccompanied by a corresponding affect on the DC voltage output by the power supply. This person should have understood that in raising this objection he took on an obligation to demonstrate the validity of his objections, in a manner perfectly thorough as to leave no doubt as to the correctness of his objection. His obligation was to show that it is possible for the output current of a typical power supply to be affected with no corresponding affect observable in the output voltage, and to show that this can occur as a result of distorted AC mains when and only when the distortion occurs at the peaks in the AC waveform presented to the power supply. Eventually Amir got fed up with it and repeated the demonstration with the clipping applied at the peak of the AC waveform. The result was exactly the same as it was previously. The complainer offered nothing in the way of apology or acknowledgement that his objections were not well founded.

There are strong similarities between what that other person did and what you are doing. The onus is on you to show that the distortion that Amir applied is not realistic. I doubt very much that you will succeed in this if all you have is reason why THD is not a good characterization of distortion on the AC mains. I do not know whether you think that this is all you need to show, but if it is, this is a misunderstanding on your part. What you need to do:

(1.) Identify/define the characteristics of AC mains distortion that are typically encountered, i.e., realistic, and such that typical audio components consequently present audible distortion in their outputs.

(2.) Provide proof that the distortion that Amir applied in his demonstration is not realistic, i.e., does not satisfy those characteristics.
 

audio2design

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@b4nt, when you include graphs and articles, when writing responses to what other people have written, you need to try much harder to make certain that the other person actually did say something that is refuted by the graphs and articles. Moreover, when you misquote another person, the misquote is a misquote no matter if it occurs through omission of critical pieces of what the other person had written, especially when it is manifest that the pieces you omitted are absolutely critical to the correct interpretation of the part you quoted. Your defense of the misquote reveals a basic lack of sincerity, which fact is the only reason I am now bothering to draw attention to it again.



I had written this: "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:" Immediately following that statement, I gave the two conditions on which improvement of the SQ, by an external power conditioner, is inherently predicated. The two conditions are that (1.) Distortion routinely exists on the mains, sufficient in severity such that typical audio components are not able to deal with it, and (2.) The external power conditioner is able to correct the problem by presenting the audio components with an undistorted or less distorted AC mains. These two conditions are the necessary and sufficient conditions by which an external power conditional may be beneficial.

In your response (it was the only one that anyone wrote), you did not question whether the two conditions I identified are the necessary and sufficient conditions. Instead, your response treated those two conditions as claims I was making. This is exceedingly, patently bizarre. In essence you asked me to defend those two conditions as though I had claimed that they are true conditions. It makes no sense at all, for you to have interpreted what I wrote in the manner that you did. As such, it is difficult for me to seriously regard anything that you have to say.

I was very much impressed with Amir's demonstration. Yet, as always, several people objected. One person in particular objected excessively and boorishly. His principal objection was that distortion in the AC voltage matters only if it occurs at the voltage peaks such that there is an affect on current output from the power supply, unaccompanied by a corresponding affect on the DC voltage output by the power supply. This person should have understood that in raising this objection he took on an obligation to demonstrate the validity of his objections, in a manner perfectly thorough as to leave no doubt as to the correctness of his objection. His obligation was to show that it is possible for the output current of a typical power supply to be affected with no corresponding affect observable in the output voltage, and to show that this can occur as a result of distorted AC mains when and only when the distortion occurs at the peaks in the AC waveform presented to the power supply. Eventually Amir got fed up with it and repeated the demonstration with the clipping applied at the peak of the AC waveform. The result was exactly the same as it was previously. The complainer offered nothing in the way of apology or acknowledgement that his objections were not well founded.

There are strong similarities between what that other person did and what you are doing. The onus is on you to show that the distortion that Amir applied is not realistic. I doubt very much that you will succeed in this if all you have is reason why THD is not a good characterization of distortion on the AC mains. I do not know whether you think that this is all you need to show, but if it is, this is a misunderstanding on your part. What you need to do:

(1.) Identify/define the characteristics of AC mains distortion that are typically encountered, i.e., realistic, and such that typical audio components consequently present audible distortion in their outputs.

(2.) Provide proof that the distortion that Amir applied in his demonstration is not realistic, i.e., does not satisfy those characteristics.


It is not my responsibility to apologize for a poorly implemented and poorly thought out test, and frankly, is still poorly implemented because 1) It only looks at one component in isolation, 2) It does not look at what the harmonic impact is in the important current waveform, and 3) It does not inject higher frequency harmonics, only relatively low frequency harmonics.

You were impressed because of a lack of knowledge, which unfortunately happens too often in audiophiledom. I was not impressed due to the obvious flaws in the initial test, and I am still not impressed with continued flaw.

Just a p.s. This was marked "no change", and yes, there total THD+N did not change much, but 15+ db change of a fairly significant harmonic pretty substantial, and while it may be masked by higher peaks, audibly, they are both large enough to near audible limits.


1630181408427.png
 

audio2design

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On my side, I noticed the D90se is built using a CE compliant SMPS. I assume the D90se is CE compliant also.

There are maybe a lot of tests you could skip so :)

View attachment 147634

Using a CE marked power supply or power supply marked with an FCC logo confers absolutely no EMI emissions certification to the end product. Literally none at all. It is also absolutely not a guarantee your product will pass emissions testing for conducted emissions.

I have tested a product with an FCC Class-B power supply that failed FCC-Class-B emissions by over 20db, which is not a small amount to fail by. No issue with the power supply. The issue was with the design of the product.
 

Grooved

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What did you get if you run this without phase and EQ engaged? Looks like you might want to trim the last 4 seconds too.

Hi,
I've reduced the length (beginning and end) to match the original file, to get the same number of samples.
We can see that both DAC and ADC are not synced as the samples are not done at the same time and it may change a bit the signal :

Original :
sample original.PNG


Recorded (same for both Furman and Wall jack :
sample Furman.PNG


After that, I did the test one more time with EQ and Phase correction, and another without both corrections.
With or without EQ and Phase correction, we see that the record done with the Furman is pretty much the same than without

Furman with EQ+Phase correction :
DW 1 Furman CUT.PNG


Wall jack with EQ+Phase correction :
DW 1 Wall Jack CUT.PNG


Furman without EQ+Phase correction :
DW 1 Furman CUT_without EQ-phase.PNG


Wall jack without EQ+Phase correction :
DW 1 Wall Jack CUT_without EQ-Phase.PNG
 
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