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Why an AC Power Cord cannot make a difference

If you consider that the power supply is only connected to the mains only 10 percent of the time, during the charging pulses ( disconnected by the reverse bias diodes), in normal operation you can think of the PS as a power buffer.
I certainly hope not as if were a 'power buffer' it would be very inefficient yet warm space heater.
Do you mean "energy buffer"?
 
Additionally, if "power is power" why is there a whole science behind properly engineered IEC power receptacles with integrated EMI filtering?
That is about the receptacles though and filtering may well be needed.

The cord itself does not matter (much) unless for some reason a device needs to be connected using screened cables.
Of course... plugs would have to be decent and the proper gauge for the application is needed.
There would be little point in that though when using IEC inlets.
In such a case the cable would have to be fixed and the shield connected directly to the chassis.
Furthermore the source side then also would not be using regular mains plugs but also be connected with its shield to the (shielded) source.
 
That is about the receptacles though and filtering may well be needed.

The cord itself does not matter (much) unless for some reason a device needs to be connected using screened cables.
Of course... plugs would have to be decent and the proper gauge for the application is needed.
There would be little point in that though when using IEC inlets.
In such a case the cable would have to be fixed and the shield connected directly to the chassis.
Furthermore the source side then also would not be using regular mains plugs but also be connected with its shield to the (shielded) source.
Sure, but that is only a question on _where_ the components of EMI/AC filtering are located.

Now, I would consider it a horrible design for a regular piece of audio equipment to require EMI/AC filtering and yet not HAVE it on it's power port. But that would be an example of a difference.

But the obvious and more common example which many (most?) forget about is whether or not the power cord has either a 2 or 3 pole connector. That's often related to if the device has a Type I or Type II power supply.

A lesser one is a polarized versus non-polarized plug.

In any event, there's nothing magical here.

Simply pointing out one should be hesitant in making absolute statements.
 
Additionally, if "power is power" why is there a whole science behind properly engineered IEC power receptacles with integrated EMI filtering?

What if the people who properly engineered the IEC power receptacles with integrated EMI filtering come and tell you power cords don't matter?

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What if the people who properly engineered the IEC power receptacles with integrated EMI filtering come and tell you power cords don't matter?

View attachment 419908
I would then turn around and ask them why they designed both the C13/14 and the C17/C14 style receptacles since it doesn't matter!
 
c17 is for double insulated and cannot be accidentally plugged in a device that requires safety ground.
2 vs 3 wire cable.
 
c17 is for double insulated and cannot be accidentally plugged in a device that requires safety ground.
2 vs 3 wire cable.
Indeed.
Perhaps people are misinterpreting "cables CAN matter (in certain specific conditions)" with "cables ALWAYS matter?"

I should have used the more common example of mixing/matching polarized/non-polarized Type-A plugs, and the usual corresponding C7 and C7P.
Ignoring the safety aspects, it "CAN matter" when connecting two or more devices with Type-2 power supplies.

It's something to be aware of especially when using older Japanese equipment.
 
Well mains cables matter a lot. without them mains fed appliances won't work.

In the Netherlands (and some other E.U. countries) mains plugs are not polarized (In France they are as they have a ground pin)
 
I used the word "buffer" to illustrate the separation of the AC source from the DC output. I realise it's not the exact, proper way to describe the situation electronically. Despite this, I stand by my assertion that as far as the amplifier circuit is concerned, it is powered by DC and provided the power supply is doing its job, the AC source energy has no influence on the operation of the amplifier if it is within specification. As to EMI and RF filtering, both can be addressed in the power supply circuit. In addition, a mains supply cable is not part of the signal chain and does not require a physical shield, there is no benefit whatever to incorporating a shield into its construction. The OP on this thread included some graphic evidence that there is no measurable difference between mains cables. It's no surprise that in a sighted test, the listener will be predisposed to hearing a difference if a plain OEM cord is swapped out with a ridiculously elaborate (and expensive) one. This is a subject we have worked through at great length on this forum.

mains_python_1.jpg


Another thing is that we almost always agree on is that if someone perceives value in this sort of accessory and that's how they want to spend their money, knock yourself out! However. where there is absolutely no support for an item like this to beneficially change the operation of the equipment it is connected to, we call that out.
 
Money grab ... the almost obligatory risers as well ... and don't forget the audiophile fuses in the mains path... they are even more important than the loaded with food anaconda power cords.
And yes .... all of that mains current flowing through thick wires first passes through many miles (km) of wire from a station to the house through circuit breakers (or fuses), wall wiring and after the mains cable it passes through a thin piece of fuse wire inside the device and through the also relatively thin primary winding wire (inductor) of the mains transformer.... that is if there isn't a mains filter in its path.

Nah... it matters .... that piece of wire between the wall outlet and that little fuse wire right before the mains transformer or rectifier (SMPS).
 
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Money grab ... the almost obligatory risers as well ... and don't forget the audiophile fuses in the mains path... they are even more important than the loaded with food anaconda power cords.
And yes .... all of that mains current flowing through thick wires first passes through many miles (km) of wire from a station to the house through circuit breakers (or fuses), wall wiring and after the mains cable it passes through a thin piece of fuse wire inside the device and through the also relatively thin primary winding wire (inductor) of the mains transformer.... that is if there isn't a mains filter in its path.

Nah... it matters .... that piece of wire between the wall outlet and that little fuse wire right before the mains transformer or rectifier (SMPS).
But you don't understand; you must just believe. Beee-leeeeeve! Don't question it. Ours is not to wonder why; just invert, and multiply!
 
Perhaps people are misinterpreting "cables CAN matter (in certain specific conditions)"
Please can you give an example of a specific (in a real world use case) condition with a specific device, in which a different power cable has made an objective, measurable and audible difference to the output of an audio device. 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.

Because it feels like you are in a world of "well anything is possible" which while true, omits the "but most of those possibilities are so close to zero probability, that we don't need to consider them".
 
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I used the word "buffer" to illustrate the separation of the AC source from the DC output. I realise it's not the exact, proper way to describe the situation electronically. Despite this, I stand by my assertion that as far as the amplifier circuit is concerned, it is powered by DC and provided the power supply is doing its job, the AC source energy has no influence on the operation of the amplifier if it is within specification. As to EMI and RF filtering, both can be addressed in the power supply circuit. In addition, a mains supply cable is not part of the signal chain and does not require a physical shield, there is no benefit whatever to incorporating a shield into its construction. The OP on this thread included some graphic evidence that there is no measurable difference between mains cables. It's no surprise that in a sighted test, the listener will be predisposed to hearing a difference if a plain OEM cord is swapped out with a ridiculously elaborate (and expensive) one. This is a subject we have worked through at great length on this forum.

View attachment 419939

Another thing is that we almost always agree on is that if someone perceives value in this sort of accessory and that's how they want to spend their money, knock yourself out! However. where there is absolutely no support for an item like this to beneficially change the operation of the equipment it is connected to, we call that out.
To fire for effect, howzabout coming out with a model that has a large bulge about 1/3 the way down from the equipment plug, so it looks like it just swallowed one of its inferior competitors, whole.
 
OK, I'll bite. What are these cases?
He seems to think "well if you don't plug it in you'll have no sound" is some kind of gotcha. :rolleyes:
 
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