... abit confused: how does a power cord affect the presentation of sound...

Expectation Bias.

i witness a friend of mine make a fool of himself when I took his over prices Power Cord to a Hifi meet-up.    JPS Allumiti or something at around £6k.

The magic chord was switched back & forth numerous times against a bog standard kettle lead.   Only the chap behind the kit knew which was connected.

No one in the room could hear a difference, aside from my pal.   When he exclaimed “Oh come on that’s night & day...”.  It was revealed the £3 kettle lead was in...


My pal learned nothing from that day.   A fool & his money are easily parted.

Hi,
they do affect the power supply of a component, wire and plug quality has different sonic characteristics, EMI control is not the same in different powercords connected to a component.

My very limited budget prevents me from believing in any of the PC or interconnect bull about SQ improvement. I do enjoy reading all the opinions though and even the scientific ones which are fairly indisputable but does the science reach the eardrums? 

Let's be logical.
It is possible that active power conditioners affect the sound of the system.

But if you are talking about 6 feet of power cord with no active component, this can have nil effect as long as it's large enough to carry easily the power being drawn by the system.

Think about it.  Behind the 6 foot power cord there is a (usually) much longer connection to your meter.  Won't that foul up the power?  OK you can up-specify that and many of us do.  But probably not with wire costing $1,000/foot.

The meter is connected in the street to the local transformer that may be 400 yards or more away. A quarter a mile of wire fouling up your system.  You don't own that wire so there is nothing you can do about it, even if you could afford the $400,000 to improve it.

Even if you improve the power cords local to the system, there's a lot more wire carrying your power that you can't touch.

Like bits are bits, in the digital domain at least, power cord is power cord, as long as it's thick enough for the job.

And snake oil is snake oil.

6 feet of power cord can easily affect and audio system, depending on where it is in the system.

The deal, ie, how it affects, how it happens... is about the instantaneous delta of the inductive collapse of the field integration of the complex model of the power cord, under high delta draw from the DUT.This area of draw or complexity of the signal in the given 'moment' is how we as humans, hear. 

100% of our hearing is coming out of what is effectively approximately 10% of the signal.

If you measure in engineering terms, this represents a vanishingly small amount of the signal, as it is weighted as a comparison to the entire signal.

If one, during measurement, ignores 90% of the signal, and then concentrates, or confines 'the entire measurement and comparison of signal' cycle, to the transients ONLY, then the measured distortions creep up into the many full percentage points area.

This is critical, as this is how the ear hears. The ear does not hear the bulk of the signal, it does not work with the bulk of the signal.

The ear hears EXCLUSIVELY via the transients and micro transients, and the differences in level and time, between said transients. It does not hear, acknowledge or know anything about the other 90+ percent of the signal.

So, when measuring... THROW OUT the 90% of the signal that means NOTHING to the human hearing system.

When we measure cables for differences, it turns out that the biggest area of change or behavioral differences between various cable,s is happening in the inductive transient collapse of the signal as it propagates in and via the cable.

Well, would you look at that. What a coincidence: It just happens to be exactly how and where the ear utilizes the signal.

Out of all the cable types in the world, there is one that is head and shoulders above the rest, in dealing with inductive collapse.

And that is Teo Audio's liquid metal audio cables.  It is utterly unique and different.

For example, if one tries to make an inductive coil out of the liquid metal, it fails to operate in the same manner as wire, it fails to behave like a known entity, in expected inductive behavior. It is unique in this characteristic, regarding all other high lass metallic and/or 'solidus' conductive pathways.

The only relatively similar pathway, the only relatable known pathway, mathematically and in pure physics descriptive terms..... is that of a gas.

A literal quantum response and behavior characteristic, not Newtonian.