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Power Cords

Thomas savage

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Some posts deleted, a reply ban has been issued to fas42 as he clearly stated he had no interested in providing supporting evidence to his theories/imaginings in this thread.

I really can't allow any more threads to descend into 'forum vs fas42's unsupported theory's and/or arguing against science and known understanding with nothing more than whimsical imaginings.


Thanks for the contributions so far guys and sorry for this interruption in discussion, as you were :)
 

March Audio

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Ok, maybe this isn't quite representative of what we want to look at, but it was already set up on my bench

current probe.jpg


We have a Soekris DAC (which I am quite impressed with), fed by a usb to i2s converter. Powered by 2x 7.5 V AC supply. DC supply conversion is done on the board. The board is running and playing music loudly into low impedance headphones

I am measuring secondary supply voltage and current. Yellow trace is voltage, green is current; 1mV=10 mA

scope_12.png


So we see the reservoir caps being charged over a period of around 3.7 ms and peaking about 500mA

Next is the current on the transformer primary side

scope_13.png


similar sort of thing, peaking 200 mA
 
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RayDunzl

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I am measuring secondary supply voltage and current. Yellow trace is voltage, green is current; 1mV=10 mA

index.php

Nice picture.

I'm a little surprised to see the flat on the transformer secondary (yellow), and now trying to imagine why it slants downward, and not upward, as well as why the +/- current measured is so asymmetrical...

No guess on the slant, the asymmetry guess is more + power draw for the chips, with lesser +/- draw for the amplification.

Looking real closely, there is a horizontal flat on the -yellow before the -green moves down, where there is no horizontal on the +yellow and the break of the +yellow coincides with the break in the +green...

Oh well.
 

Blumlein 88

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Ok, maybe this isn't quite representative of what we want to look at, but it was already set up on my bench

View attachment 5825

We have a Soekris DAC (which I am quite impressed with), fed by a usb to i2s converter. Powered by 2x 7.5 V AC supply. DC supply conversion is done on the board. The board is running and playing music loudly into low impedance headphones

I am measuring secondary supply voltage and current. Yellow trace is voltage, green is current; 1mV=10 mA

View attachment 5826

So we see the reservoir caps being charged over a period of around 3.7 ms and peaking about 500mA

Next is the current on the transformer primary side

View attachment 5827

similar sort of thing, peaking 200 mA

How DARE YOU come into this discussion and support your opinion with real measurements of real things. The unmitigated gall not to mention complete lack of respect for those with other viewpoints which may just happen not have real things supporting those contrary views is frankly APPALLING.


OH, wait a minute. This is Audio Science Review forums. Not AudioPhoolU forums. Okay, got confused for a moment. Nevermind! Carry on. :D
 

March Audio

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How DARE YOU come into this discussion and support your opinion with real measurements of real things. The unmitigated gall not to mention complete lack of respect for those with other viewpoints which may just happen not have real things supporting those contrary views is frankly APPALLING.

OH, wait a minute. This is Audio Science Review forums. Not AudioPhoolU forums. Okay, got confused for a moment. Nevermind! Carry on. :D

HAHAHa :)
 

March Audio

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Nice picture.

I'm a little surprised to see the flat on the transformer secondary (yellow), and now trying to imagine why it slants downward, and not upward, as well as why the +/- current measured is so asymmetrical...

No guess on the slant, the asymmetry guess is more + power draw for the chips, with lesser +/- draw for the amplification.

Looking real closely, there is a horizontal flat on the -yellow before the -green moves down, where there is no horizontal on the +yellow and the break of the +yellow coincides with the break in the +green...

Oh well.

Yeah, not quite what I was expecting either, but that's the beauty of measuring whats actually going on instead of guessing and imagining like so many audiophile fantasists do:)

That current draw is quite near the limit of the transformer (0.6A), so the voltage may be collapsing a bit in response, but in a straight line ?!?

You are spot on correct about the asymmetry

Power Consumption [1130]
  • Positive Rail: .18A, 10V
  • Negative Rail: 0.06A, 10V
  • Total: 2.4W
  • The positive supply draw about 3 times as much current as the negative; the current is almost independent of input voltage.
 
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March Audio

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Oh, just measured the transformer secondary with no load. Looks like the incoming supply waveform isn't exactly beautiful :) Lots of people with air con on :)

scope_15.png
 

March Audio

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Also we have a lot of people with solar panels around here with inverters feeding back into the grid. Must have an impact.

This raises whats a pertinent point to my mind. This sort of mains distortion isn't unusual. A decent bit of hifi kit needs to be designed to cope, if it doesn't its a bad design.

Going back to the OP, it seems to me that the Shityata test and results haven't any relevance.
 
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RayDunzl

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Going back to the OP, it seems to me that the Shityata test and results haven't any relevance.

In a video for a power conditioner they used a paper shredder as the noise source.

Which is fine, but if I'm shredding paper, I might not be in critical listening mode.
 

March Audio

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In a video for a power conditioner they used a paper shredder as the noise source.

Which is fine, but if I'm shredding paper, I might not be in critical listening mode.

OK, that's a different topic to the transient current delivery one.

Its not debateable that there is noise and distortion on powerlines, and that products can help filter said noise. However the real question is what of that noise gets through the power supply and actually affects the audio output. They are testing the wrong thing.

Interesting thing to note is that the cable they demonstrate with special geometry and superior transient capabilities is more likely to let high frequency noise through. HAHAHa :)
 

March Audio

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So yes they really have rediscovered ohms law.

So if transient current delivery of the mains supply is so critical to sound quality, what is happening to the sound quality 100 times every second when the mains voltage is at zero and the current delivery capability is also zero?

Can someone show me an audio component that actually needs 1.2 kAmps of instantaneous current delivered in 10 usecs?

.....and if 1.2 kA is required on the transformer primary, what is the secondary trying to supply OMFG !:eek:
 
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DonH56

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Nice work BE718! That is what I have measured in the past, and what my simulation generally showed.

Well, let's see, most homes these days use 14 AWG from service to outlet for a standard 15 A outlet. Assume 100', at about 2.5 m-ohms/foot (source: https://en.wikipedia.org/wiki/American_wire_gauge ), and you have 0.25 ohms of wiring from service to outlet. Not counting all the wire up to the point, which is heavier guage but much longer, and ignoring contact and breaker resistance and all of that. Now 1200 A * 0.25 ohms = 300 V peak voltage drop. Seems a bit high. Note 120 Vrms = 339 Vpp. Clearly we all need high-power local clean power sources to prevent our amplifiers from sounding like crud. Wired with superconductors.

I continue to shake my head at the way you can misapply science (and engineering, mustn't forget I am a lowly engineer, not a true scientist as our revered but apparently absent member highlighted long ago ;) ) to sell stuff to the ignorant and/or gullible. A lot of well-meaning folk simply do not have the knowledge to refute this kind of stuff, or the experience to call them out when the real world enters the picture.
 
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RayDunzl

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Now 1200 A * 0.25 ohms = 300 V peak voltage drop. Seems a bit high.

Ya, seeing as there be only 170Vpk to start with... at least here...

---

I'll just have to file my little 15A Equitech under guilty pleasures, I guess...

And now I want to run out and buy a modern scope again (I'll forget about it tomorrow).

---

Helpful Homemaker Guesstimating Hint:

If you want to know the voltage drop and guestimate peak currents, probe the Neutral vs Earth on an outlet.

The voltage on Neutral will diverge from Earth according to the amount of 'return' current. I read 4Vpk .

upload_2017-3-11_13-37-4.png

Neutral: 4Vpk and Hot: about 160Vpk and Earth: invisible flat line in the middle

Multiply by 2 for the total drop for the loop.

I estimate 80 feet and .28 Ohms and get 14.28Amp peak. The Kill-A-Watt reads 5.07Amp on the rack, and the PC is on the same branch (about 250W with monitors).

Here's an extensive wire table: http://www.calmont.com/pdf/calmont-eng-wire-gauge.pdf

---

All this worrying has me considering running an isolated Romex 10AWG with a 20A outlet because if I have the stereo on and the PC and run the vacuum cleaner AND turn on the kitchen overhead lights it pops the breaker since there's just too much on this branch circuit.

$100 for 100 feet at Lowes.

https://www.lowes.com/pd/Southwire-Romex-SIMpull-100-ft-10-3-Non-Metallic-Wire-By-the-Roll/3138981
 
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tomelex

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Nice work BE718! That is what I have measured in the past, and what my simulation generally showed.

Well, let's see, most homes these days use 14 AWG from service to outlet for a standard 15 A outlet. Assume 100', at about 2.5 m-ohms/foot (source: https://en.wikipedia.org/wiki/American_wire_gauge ), and you have 0.25 ohms of wiring from service to outlet. Not counting all the wire up to the point, which is heavier guage but much longer, and ignoring contact and breaker resistance and all of that. Now 1200 A * 0.25 ohms = 300 V peak voltage drop. Seems a bit high. Note 120 Vrms = 339 Vpp. Clearly we all need high-power local clean power sources to prevent our amplifiers from sounding like crud. Wired with superconductors.

I continue to shake my head at the way you can misapply science (and engineering, mustn't forget I am a lowly engineer, not a true scientist as our revered but apparently absent member highlighted long ago ;) ) to sell stuff to the ignorant and/or gullible. A lot of well-meaning folk simply do not have the knowledge to refute this kind of stuff, or the experience to call them out when the real world enters the picture.

What you say surely makes sense. The thing about some of those well meaning folk is they have a choice, believe the experts or believe the bizarre stuff on WBF, where they are going on right now about power cords and coming up with the same old thing, wider width, blacker blacks, better stereo seperation, all the subjective expectation biased stuff as usual. I think that folks want to increase or better their system, and so they look for what is out there, and whenever there is a need, there will always be some one to fill it, just like many folks when they lose a loved one, they might turn to those people who claim to be in touch with the dead and all. Its understandable and its their money, and their journey, but when they go to the other side based on what they hear and would not do a blind test, they are just deluding themselves, and folks seem to like to do that as well, and that is where logic exits and the mystery of the brain enters..
 

Thomas savage

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What you say surely makes sense. The thing about some of those well meaning folk is they have a choice, believe the experts or believe the bizarre stuff on WBF, where they are going on right now about power cords and coming up with the same old thing, wider width, blacker blacks, better stereo seperation, all the subjective expectation biased stuff as usual. I think that folks want to increase or better their system, and so they look for what is out there, and whenever there is a need, there will always be some one to fill it, just like many folks when they lose a loved one, they might turn to those people who claim to be in touch with the dead and all. Its understandable and its their money, and their journey, but when they go to the other side based on what they hear and would not do a blind test, they are just deluding themselves, and folks seem to like to do that as well, and that is where logic exits and the mystery of the brain enters..
Amir hit the nail on the head with the 'elasticity ' comment/post ( got abused for the trouble, even though he's totally RIGHT) , they are addicts plain and simple. It's a fairly harmless addiction, though the dissatisfaction it spreads amongst folks who can't buy all the crap they are told makes things 'so much better ' is considerable.
 
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RayDunzl

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Thomas savage

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quote_icon.png
Originally Posted by Folsom
"Everyone is basically retarded" good addition Amir...

Amir replied ..,
No, it is the opposite. Everyone is born with the same human abilities. You cannot override those no matter how great you think you are. What is retarded is to think that all the variables that go into your perception are under your control. They are not.

Think of driving to and from work. It being routine, not much enters into your memory. Now think of sightseeing using your car. This time you pay attention and commit a lot more to memory. This is called "elasticity."

Your hearing is elastic. When you swap something and then pay attention to what may have changed, you now have a totally different experience. The short term memory which is under 20 seconds, gets filtered differently and what gets stored in long term memory distinctly different. You can now hear details, air, more bass, etc. that you took for granted before.

This is how your brain and hearing system works. You cannot do anything about it but be aware of it and conduct experiments which guard against it.

We can objectively prove all of this by for example, playing the same thing twice and have you perceive better bass, detail in one of those rounds and not the other. You will swear that the two sounds are different if I did not tell you they are identical. Heck, even knowing they are identical you can "hear" differences.

@amirm you are my hero for posting the above truism.. its total rejection at WBF is a shocking indictment of their addiction psychosis.

http://www.whatsbestforum.com/showt...ith-after-market-cords-and-conditioners/page2
 

tomelex

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Of course, you can take anything to an extreme, whether the extreme show in this thread, or make your input power cable gauge so physically small that there will be voltage drops and resultant modulation of your unregulated power transistor supply, the extremes as show in this thread by this power cable manufacturer is going the wrong way, but to separate yourself from the other extremists, I guess you need to be more "extremer"

Amir has thrown down the gauntlet over there with $10K for proof, however, he needs to make the other person ALSO lose their own $10K if they cant prove it. Shuts the golden ears down every time when they have to prove their hearing abilities, instead of thinking about it, that if you cant hear it it does not matter, they want to be in their fantasy world.
 
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