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Why an AC Power Cord cannot make a difference

USA already has 240V with 2 x 120V but you guys use it for the washing machine. Must be one audiophilic washer.
 
USA already has 240V with 2 x 120V but you guys use it for the washing machine. Must be one audiophilic washer.

Usually the dryer, but you're right, it is only brought out for special occasions. Well pump motors, electric kitchen stoves, air compressor in the garage, etc.
 
It seemed like a deliberate but misplaced moving of the goal posts. Maybe due to a very literal reading of "Power cable cannot make a difference".

Almost all of us know that from the start, Pavel's OP was addressing the topic of "Why expensive/snake oil power cables will not make a difference to sound quality compared to the exact same setup using a $3 Monoprice power cord".

But if someone wanted to read the title literally, whether to be intentionally argumentative or because they cannot extrapolate the actual topic of interest from it, then I get why one might argue from the stance of "Well, if there is a grounding or mains wiring defect, than here is an instance where the power cable can be modified to make a differnece".

So maybe it just needs to be repeated plainly and bluntly: when discussing pwoer cables not making a difference, it is in regard to an otherwise properly working system and comparing a standard power cord (wired properly) to an expensive/snake oil power cord (also wired correctly).

Perhaps we should not be casting aspersions upon others here.

Perhaps I should not have made my observations on the possible effects of leakage current and it's phase in a new thread rather than adding it to one which seems to carry significant baggage.

Nor is it dependent upon poor equipment design, thou it can certainly exasperate the it.

It primarily involves the proliferation of Class II power supplies in audio equipment and given the measurement focus of this board I am surprised there is not more discussion of it here.
 
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True, a Class II Double Insulated appliance (including audio equipment) can must not be modified.
However, one may use a Class II power supply and reference it's output to ground. I've seen that more and more as many power supply manufacture's are reducing their number of offerings with many newer designs being offered only in Class II.

For example, the HyperX SMPS1200Axxx documentation only show a two wire connector for Line (Phase) and Neutral. However, looking at pictures it appears more builders are using the standard IEC C13/C14 power connector. Now, it's entirely possible it's connected through the frame though they appear to be using non-conductive standoff posts.
Pretty sure I found a Y cap to a grounding pad around one of the mounting bolts .
 
I use a power cable to my AVR that has a screen. I made it for this purpose, because of the limited room behind it, all kinds of analog and digital audio, antenna, network and speaker wires mix up. My theory is that it will reduce the noise the AC mains line to the AVR can induce into other components. The AC line has the highest voltage and current flowing. So nothing Voodoo.
Cost was less then 20€ for connectors and LAPP cable (LAPP is a German cable specialist for anything but audio). Lapp 1135103 Ölflex Classic 110 CY 3G

So for some special situation a more specialized AC cord could make sense.
Another thing, my audio system has a dedicated, uninterupted line to it's own fuse in the fuse box. I could eliminate switching noises with this installation by using a 230V phase with no loads like washing machine or refridegerator.
Such scientificaly explainable measures are exploited by crooks to sell their useless stuff.

Maybe an idea for a power cord test: We use an osciloscope to watch the noise at the main rectifier diodes of an amplifier. There should be some change of the diode noise with an different "audiophile" AC cord. If not, there is no way that the AC cord could change the sound of the amp.
 
However, one may use a Class II power supply and reference it's output to ground. I've seen that more and more as many power supply manufacture's are reducing their number of offerings with many newer designs being offered only in Class II.

For example, the HyperX SMPS1200Axxx documentation only show a two wire connector for Line (Phase) and Neutral. However, looking at pictures it appears more builders are using the standard IEC C13/C14 power connector. Now, it's entirely possible it's connected through the frame though they appear to be using non-conductive standoff posts.
Pretty sure I found a Y cap to a grounding pad around one of the mounting bolts .
Class I and II refers to the appliance, with the chassis (and the clearance/insulation) and stuff. The power supply alone is not classified by this class.

You will find that this information will clear out many pages worth of confusion in this thread
 
...... rather than adding it to one which seems to carry significant baggage.
Not so much baggage - just a different topic.

In particular the type of power cable changes that apply to the snake oil products that promise improved audio performance due to..... basically audiophile woo.

Your discussion of leakage/class II devices etc has no bearing on things that can be solved by purchasing a different (compliant) cable, and in fact can only be influenced by user modification of a cable to make it non compliant.

In other words, your whole topic of discussion here is off topic for the thread. Your continued insistence on discussing them even when you have been informed of this comes across as trollish. In particular, It is also muddying the waters on the main topic of this thread, in that less well informed members might think you are arguing that snake oil products are not snake oil after all.

I'm going to quote (again) from a couple of posts above.

And while we are about it, lets keep it to the type of cable difference other than "those basic requirements to make it work correctly and safely" which are not really what the thread is about.

So maybe it just needs to be repeated plainly and bluntly: when discussing pwoer cables not making a difference, it is in regard to an otherwise properly working system and comparing a standard power cord (wired properly) to an expensive/snake oil power cord (also wired correctly).

So yes:
Perhaps I should not have made my observations on the possible effects of leakage current and it's phase in a new thread

Is a good idea.
 
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Yes the topic is really to discourage people to buy silly audioquest cables etc .

In the next ( sadly inevitable ) cable tread , I will argue that RCA cables makes an enormous and audible difference if they are 1000 meters long .

( troll now blocked , you should all do the same )
 
Maybe an idea for a power cord test: We use an osciloscope to watch the noise at the main rectifier diodes of an amplifier. There should be some change of the diode noise with an different "audiophile" AC cord. If not, there is no way that the AC cord could change the sound of the amp.

If diode noise was making it onto the DC rails, you'd have a really bad power supply. Either it would be faulty or just poorly designed. I don't know another way to describe how the AC energy going into the transformer, then into the rectifier bridge and then gets smoothed out by the caps and presents at the output terminals as DC. The output energy is completely different to the input energy, it has been PROCESSED. It's a one way street, AC is transformed into DC and the amplifier cannot be influenced by the AC or any slight defect in the AC waveform because its GONE! In a properly designed linear DC power supply, no elements of the AC waveform will affect the DC at the output. This is why a meter or two of mains cable or a fuse can not influence the performance of the audio amplifier. If you can't understand this basic principle, you have no business speculating or commenting on issues of an electrical nature.

Power-supply-circuit-for-amplifier-board.jpg
 
These days, yes, if the plug is molded on, you have to cut it off, strip wires, and put a new plug on it because of polarized plugs and outlets. However... most of the cheap wallwarts I have plug in directly rather than having a cord and don't have polarized prongs, so you can just physically turn them the other way. Easy peasy.

Yes, you could swap the wall socket's wires after ensuring the breakers are off! :cool:
In my day, we used to just snip the "ears" off the old-school (US) polarized two-prong plugs. :facepalm:
I guess some determination and grit (ahem, literally) would be needed to grind or otherwise wear down the wider prong on most modern polarized plugs in the US.
 
If diode noise was making it onto the DC rails, you'd have a really bad power supply. Either it would be faulty or just poorly designed. I don't know another way to describe how the AC energy going into the transformer, then into the rectifier bridge and then gets smoothed out by the caps and presents at the output terminals as DC. The output energy is completely different to the input energy, it has been PROCESSED. It's a one way street, AC is transformed into DC and the amplifier cannot be influenced by the AC or any slight defect in the AC waveform because its GONE! In a properly designed linear DC power supply, no elements of the AC waveform will affect the DC at the output. This is why a meter or two of mains cable or a fuse can not influence the performance of the audio amplifier. If you can't understand this basic principle, you have no business speculating or commenting on issues of an electrical nature.

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What you write is only right as long as the PS is not loaded. As soon as you place a load at the output, you will be able to see all kind of noise dancing on the DC. The DC will not be a flat line any more. Of course, you can only see this with an osciloscope in AC mode, preferable an older analog one. If a mains cable could influence the sound of an amplifier, this noise would be the first indicator of something changing. It is the only direct connection the electronics have to the outside mains. I'm quite sure this will not happen, so no mains cable will be able to improve an amps sound.
Of course, you could use a resistor cable and find an improvement by using a normal one without this restriction. So all kinds of ways to cheat in a public demonstration.

About my screened mains wire, this is to keep influence from the AC wires away from sensitive, outside cables in direct proximity. Not to improve the amp from the mains side!
 
I agree, if you load the supply, you will see more ripple but as far as mains artefacts go, you'd really need to be putting the PS under stress. This scenario is also very unlikely when we're considering domestic HiFi. I think the average is around 7-10 watts for normal listening so most decent amplifiers will be idling realistically, let alone a high-end monster monoblock!

stupid_monoblock.jpg

Phwoooaaarrr!
 
How do we even fix what we don't know? What undesirable behavior of the mains cable are we talking about?

A highly resistive cable would form a nice RC filter, isn't that what snaker-oilers want?
 
Power cable can make a difference in an actual system, indirectly.

If you have a class-I ground loop scenario, then a higher resistance of the cable can help because then the second GND connection via the interconnects has better chances to be lower (dominating) impedance. A weapon of choice in many recording studios is a large 50m cable drum which creates a significant resistance and common-mode inductance.

A second aspect is EMI (electromagnetic interference). There is a reason why ferrite-loaded mains cables do exist (industrial stuff from Eupen cable company). Such a cable, or at least lots of clamp-on ferrites on a regular cable, can improve the EMI situation big time. In an audio system this can reduce background noise. Clamp-on ferrites should generously be used on each and every cable in a system.
 
Power cable can make a difference in an actual system, indirectly.

If you have a class-I ground loop scenario, then a higher resistance of the cable can help because then the second GND connection via the interconnects has better chances to be lower (dominating) impedance. A weapon of choice in many recording studios is a large 50m cable drum which creates a significant resistance and common-mode inductance.

A second aspect is EMI (electromagnetic interference). There is a reason why ferrite-loaded mains cables do exist (industrial stuff from Eupen cable company). Such a cable, or at least lots of clamp-on ferrites on a regular cable, can improve the EMI situation big time. In an audio system this can reduce background noise. Clamp-on ferrites should generously be used on each and every cable in a system.
First I can understand - though it seems a sledgehammer solution compared to other more appropriate ones, such as downstream isolation, or balanced interconnect.


Second I'm not so convinced. Ferrite loaded mains cables are about RF emissions from the device. They are generally used to get a piece of kit through the conducted emissions test requirement - which only specifies limits from150kHz up to 30MHz and I don't think they do much until you get up from the bottom of that range. They do little to nothing at audio frequencies.
 
Clamp-on ferrites should generously be used on each and every cable in a system.
I would say only when needed. Gear should be immune and not emit too much (conducted as well as radiated).
There really is no need for any heroic measures like extra filters, ferrites, capacitors, shielded mains cables etc. in most cases. One can even make things worse in some cases even.
Also, not all ferrites are equal and looping a cable a few times through one ferrite also greatly improves effectivity.
 
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They do little to nothing at audio frequencies.
Of course not. But they block RF frequencies, both coming out of a device as well as ingressing into a device. And RF contaminating a device can lead to demodulation which can make the disturbance audible.
 
I would say only when needed. Gear should be immune and not emit too much (conducted as well as radiated).
You name it, "should be"... but often it isn't beyond to what's required to pass EMC regulations which are sloppy when it comes to audio artefacts produced by EMI.

The motivation for my post was to show that mains cables may actually alter system performance in a real world complex scenario.
 
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