Impact of AC Distortion & Noise on Audio Equipment

[Spkrdctr]

How do you propose that the mains borne control signals be fixed? They are fed into your house from the street supply. What about local electrical equipment, your next door neighbour's welder, the motor switching noise from the factory in the next block. Getting it fixed is not always possible. Or rather the fix is to buy a power conditioner. Seriously, power conditioners are not some weird snake oil invented to fleece audiophools. The Audio branded ones are, but reputable manufactures make power conditioners for sensible reasons and have done so for decades.

I think everyone will agree with you. The problem is as you know that most, overwhelmingly are sold (audio versions) to audio tweakers or people that have been bamboozled by corrupt marketing. Yes, I mean lies and corrupt marketing on a massive scale. If you truly have a problem, then yes, it is needed. But I would say most audio regenerators are sold to audiophools who believe that they have massively dirty AC mains power even though all of their equipment works perfectly and sounds great. They worry about the "possibility" of having dirty AC power! Unbelievable.

 

[amirm]

Amir, when you run these tests are they just the devices without a signal or do you play music/test signals when testing?

What kind of question is that? Did you not see the test tone running during the measurements?

That power source is what I use day in and day out to listen to music, with powered speakers and headphones. And with multiple devices and paths. Same power source has produces superlative measurements on hundreds of devices across many types of test signals.

 

[amirm]

As you’d mentioned previously fluctuations in power could lead to drops in peak output, if say there was a sudden sound, a quiet sound then a sudden sound etc whilst power fluctuated this could lead to “degraded recovery of peak output” which could make a system sound “a bit off”?

I never said that. I said that if the peak AC voltage is lower than nominal, and power supply in your amplifier is unregulated, you may get a tiny bit less output. The word "modulation" was not in that sentence. The power supply even if unregulated, has capacitors to deal with this and at any rate, feedback will make sure distortion is kept under control until you clip.

 

[amirm]

Then again, it might be non representative of people needs or expectations.

The people's expectations -- and I know many -- is that by deploying such boxes, perfectly performing system with zero pops, clicks, or hum, all of a sudden are elevated to another sonic level. These are the same people who change their outlets and report improvements. Or even screws used in such power sockets! Scenarios you have been making up is not remotely common characteristics of why people buy such gear.

Your lab could be an almost ideal one, with DUTs (no more) and with controlled power/sources/listeners.

Oh? How did it become an ideal one? Did you not see the spectrum of my AC?

This outlet has my PC workstation with 16 cores and GPU whaling away. It also feeds my Audio Precision analyzer and my RME ADI-2 DAC I am using to listen as I test things. I probably have half a dozen loads plugged into the same power strip. If this is "ideal" then you have a very screwed up notion of such.

Fact is that 99.99% of the people do not hear any interference in their audio system as otherwise, it would be a massive problem for the industry to solve. I have explained why and how our hearing is not sensitive to low frequencies and naturally can't hear high frequencies above 20 kHz. You are blessed this way. This is on top of your equipment -- even cheap and crappy ones -- having direct and specific mechanisms to deal with noise and AC distortion.

So you want to say that before you drink every glass of water in your home, you should have it tested by a lab, you go right ahead. I am not here to entertain the illogical.

 

[Wes]

T
So you want to say that before you drink every glass of water in your home, you should have it tested by a lab, you go right ahead. I am not here to entertain the illogical.

OOOOOHH!!! Baaad example!

 

[Helicopter]

 

[Headchef]

I never said that. I said that if the peak AC voltage is lower than nominal, and power supply in your amplifier is unregulated, you may get a tiny bit less output. The word "modulation" was not in that sentence. The power supply even if unregulated, has capacitors to deal with this and at any rate, feedback will make sure distortion is kept under control until you clip.

sorry if I’m misquoting you, I was referring to when you said “Yes, your peak power availability may be reduced due to voltage sag. What else is new? That has nothing to do with quality of the power.”

I’m just trying to figure out why my system sounds better with a Keces bp-600 running it than from the undoubtably poor mains I have here. I would honestly rather that I didn’t need such a thing but there’s an audible difference in the quality of audio reproduction with it in place. I’m not a fan of buying things for buying things sake, I would genuinely prefer to spend my money on something else! I’ve had the mains checked out by an independent electrician AND our electric supplier and their consensus was to get some form of power conditioning & surge protection. Yes we have an abnormal situation as we live above our restaurant but that I’m afraid is unavoidable.

I’m simply trying to understand what it is with this thing that’s bringing the improvement and why.

 

[Purité Audio]

Your imagination.
Keith

 

[Headchef]

Your imagination.
Keith

Funny. No.

 

[Doodski]

Funny. No.

I'm not being funny or whatever. Have you done a blind listening test of the system with and without the power conditioner?

 

[b4nt]

The people's expectations -- and I know many -- is that by deploying such boxes, perfectly performing system with zero pops, clicks, or hum, all of a sudden are elevated to another sonic level. These are the same people who change their outlets and report improvements. Or even screws used in such power sockets! Scenarios you have been making up is not remotely common characteristics of why people buy such gear.


Oh? How did it become an ideal one? Did you not see the spectrum of my AC?

This outlet has my PC workstation with 16 cores and GPU whaling away. It also feeds my Audio Precision analyzer and my RME ADI-2 DAC I am using to listen as I test things. I probably have half a dozen loads plugged into the same power strip. If this is "ideal" then you have a very screwed up notion of such.

Fact is that 99.99% of the people do not hear any interference in their audio system as otherwise, it would be a massive problem for the industry to solve. I have explained why and how our hearing is not sensitive to low frequencies and naturally can't hear high frequencies above 20 kHz. You are blessed this way. This is on top of your equipment -- even cheap and crappy ones -- having direct and specific mechanisms to deal with noise and AC distortion.

So you want to say that before you drink every glass of water in your home, you should have it tested by a lab, you go right ahead. I am not here to entertain the illogical.

You missed that line:

And I would have liked at least to see that BK precision to feed common/diff noises and bursts pulses to confirm the DUTs you used really are imune.

 

[Headchef]

I'm not being funny or whatever. Have you done a blind listening test of the system with and without the power conditioner?

Yes, and despite stating that she would not help me with any more “of your bloody audio experiments“ the better half obliged. We’ve been doing it for almost a week now. As it’s only two plugs to swap it’s hardly like the faff of blind testing DAC’s with the db levels and their various connections. So she doesn’t mind this so much. And it doesn’t involve hiding the components as we just have to kill the power, swap them over, turn it on again. The cables are all out of view.

And yes it sounds noticeably better, it sounds as good as it did when everyone had left and everything was turned off (coffee, glass washers, extraction, etc etc), the fridges had all got down to their set temps, three floors with no lighting, etc etc.

now it sounds like that even when we’re open and everything is on When the BP-600 is the power source, She can tell it blind every time as well.

like I said our mains are not the average set up, the electricity board & an independent electrician suggested that we go down this path, as far as I know neither are in the business of selling hifi snake oil.

I am interested as to why and how it would make the improvement, my assumption is that it’s something to do with the earthing or that this thing has a big toroidal transformer in it that’s just stabilising what is in essence a ****** feed and the system is able to perform at its optimum capability without excessive interference. This is 240v 3pin uk plugs. If that makes any difference?

 

[dorirod]

And yes it sounds noticeably better, it sounds as good as it did when everyone had left and everything was turned off (coffee, glass washers, extraction, etc etc), the fridges had all got down to their set temps, three floors with no lighting, etc etc.

If it's that obvious, have you tried recording something and comparing the two outputs?

 

[Doodski]

I am interested as to why and how it would make the improvement, my assumption is that it’s something to do with the earthing or that this thing has a big toroidal transformer in it that’s just stabilising what is in essence a ****** feed and the system is able to perform at its optimum capability without excessive interference. This is 240v 3pin uk plugs. If that makes any difference?

The primary and secondary of the transformer can be thought of as tied together electromagnetically. Whatever happens in one is reflected in the other. So if there is junk on the AC mains at the transformer primary then it will be present at the transformer secondary too. That is electromagnetism 101 and it has been proven for hundreds of years. There could be filtering and smoothing at the secondary output of the transformer although from the pics of the model in question there doesn't appear to be anything significant. There are small capacitors and a inductor/transformer on the PCB. I don't know what they are doing without a schematic or some literature detailing that.

 

[Headchef]

If it's that obvious, have you tried recording something and comparing the two outputs?

I had not even thought of doing that, we’ve both been making the occasional listening notes (two note books, one to write in the date and time of any/no change and one for listening notes (time, music, observation).

however I do have all the kit required to take some professional recording, I‘ll then compare them directly, actually if I record them as WAV files I can use the frequency response analysis in Audirvāna to do a “quick and dirty comparison“.

I must warn you, the wife won’t be impressed to see the return of the Mic’s to the lounge but I’ll blame you entirely

 

[dorirod]

I had not even thought of doing that, we’ve both been making the occasional listening notes (two note books, one to write in the date and time of any/no change and one for listening notes (time, music, observation).

however I do have all the kit required to take some professional recording, I‘ll then compare them directly, actually if I record them as WAV files I can use the frequency response analysis in Audirvāna to do a “quick and dirty comparison“.

I must warn you, the wife won’t be impressed to see the return of the Mic’s to the lounge but I’ll blame you entirely

Sure thing, I bring out the UMIK1 like once or twice a year at most. We can trade blame

 

[Doodski]

@Headchef I have seen when we had a electronics repair shop located in a commercial industrial neighborhood that the AC mains voltage deviated significantly over the day. It was about +/- 15% roughly at worst case. We attributed that to loading of the AC mains at the power poles. That could in linear type power supplies cause a reduced voltage output of the transformer secondary and that in a audio amplifier will cause less power output due to the DC voltage rails being decreased. That would result in a lower volume level at the speaker output. Your conditioner does not appear to be able to compensate for that issue. When dealing with linear power supplies they have filtering/smoothing/power storage capacitors and those are supposed to be able to smooth out any aberrations of the 50 Hz 240 V that you are supplied with. The larger the amplifier then usually the larger the smoothing capacitors. AS @amirm has demonstrated they work very well when supplied with a distorted durty AC waveform from the AC mains. I would like to see a oscilloscope capture showing the 50 Hz 240 V waveform coming from your AC mains.

 

[Headchef]

The primary and secondary of the transformer can be thought of as tied together electromagnetically. Whatever happens in one is reflected in the other. So if there is junk on the AC mains at the transformer primary then it will be present at the transformer secondary too. That is electromagnetism 101 and it has been proven for hundreds of years. There could be filtering and smoothing at the secondary output of the transformer although from the pics of the model in question there doesn't appear to be anything significant. There are small capacitors and a inductor/transformer on the PCB. I don't know what they are doing without a schematic or some literature detailing that.

I wish I could help with that but I’ve got nothing but the box itself and some cables,

On the manufacturers site there’s a fair bit of information but I’m ashamed to say that my grasp of Chinese is woeful at best and I tend to avoid translation programs as they don’t tend to help but rather just confuse.

 

[John B]

Hmm analogies are reductive but they help me understand.
Basically, these devices claim to produce higher quality paper by making sure the wood going into the mill isn’t warped. Makes sense until you factor in what happens in the pulp mill and how paper is made.

 

[Doodski]

I wish I could help with that but I’ve got nothing but the box itself and some cables,

On the manufacturers site there’s a fair bit of information but I’m ashamed to say that my grasp of Chinese is woeful at best and I tend to avoid translation programs as they don’t tend to help but rather just confuse.

In your case it will require some objective subjectivism to sort this out. j/k lol... The idea of making a recording of the two states of AC mains power supply might be interesting. Record a sine wave as well as a musical signal. Also interesting would be to take a voltage reading of the amplifier output with maybe a ~400 Hz sine wave. That can be supplied with free easy to use software.