Why does better power = better sound?

Not only is there reflection noise and variable voltage/frequency, but power companies often send data through the power lines as well. There is a pile of noise on the line. Digital components tend to spew significant noise back into the power supply as well, particularly on the ground.
Now unless you are running a floating balanced output stage in your power amp your speakers are connected directly to the main grid on the negative side. The negative speaker terminal in your power amp is on the wall side of the mains transformer. The power amplifier is merely modulating the main power grid supply.
With regard to power cables, if your power lines are run in a loop through the house, then a power cable is seen as a a spur off that loop. My understanding is that if a power cable is too short then the pc will behave as if it is part of the loop, whereas if it is say 2m or more it will behave as a spur. There is a difference.

Dover, thanks for your comment.

I don't mean to be picky, but I think it would be better to refer to "reflected noise," rather than "reflection noise." The reason I make a point of saying that is that Cjl's post seemed to say that reflections caused by impedance mismatches PRODUCE noise, which is simply untrue. Reflections of noise frequencies that may be present can ALTER the effects of that noise on the system, although with little or no predictability. But impedance mismatches do not produce noise, and reflections do not occur unless there is something to reflect.

Now unless you are running a floating balanced output stage in your power amp your speakers are connected directly to the main grid on the negative side. The negative speaker terminal in your power amp is on the wall side of the mains transformer.

The negative speaker terminal will usually be connected to AC safety ground (and the amplifier chassis) through a low impedance, such as a low value resistor, or in some cases directly. The paths between AC safety ground and the primary side of the power transformer, in turn, will be via stray capacitance, especially within the transformer, and via the connection that exists between AC safety ground and AC neutral back at the electrical service panel.

In any event, the speaker will only respond to the instantaneous voltage DIFFERENCE that exists between the + and - output terminals of the amplifier. The noise levels that may be present in that difference, as a result of noise on the incoming AC, will be VASTLY lower than the noise on the incoming AC, assuming that the amplifier design is half-way decent. And the speaker, as well as our ears, will not be capable of responding to RF and digital noise frequencies anyway. The possible sonic consequences of high frequency noise on the AC line would result from intermodulation and other effects occurring in internal amplifier circuitry, that may end up affecting audible frequencies.

My understanding is that if a power cable is too short then the pc will behave as if it is part of the loop, whereas if it is say 2m or more it will behave as a spur. There is a difference.

There is no hard and fast dividing line. It depends on the frequency of each particular frequency component of the particular noise that is present, and (to a lesser degree) on the propagation velocity of the particular wiring. For the very high 8 to 13 MHz noise frequencies that were among those Cjl referred to, 2 meters is a reasonable rough rule-of-thumb approximation. Noise frequencies that are much lower would require a much longer cable length to behave as a spur.

Again, thanks for your comment, and my intention in responding is not to be picayune, and (as my earlier posts make clear) is not to deny that power cords can make a difference.

Best regards,
-- Al

Power cords finally are getting the respect they deserve.

I remember when anything more costly than the power cord that came in the box was snake oil, and only fools would part with their money to buy one.

It's interesting and educational to play around making your own power cords, or even just replacing the molded rubber ends with better ones.

When it comes to power cords, I've never experienced anything but differences in sound when you experiement with different construction and materials.

Why this is so, interests me, but I really am more concerned with the results and not the reasons.

There are a vast number of power cords in all types of configurations and cost points.

Lots of expensive ones and some at reasonable cost,especially the DIY efforts.

My advice for those who are sceptical or undecided about the merits of what a better(or different)power cord can do,need to try different power cords.

Borrow or have someone construct some for you and have a listen.

If you feel your stock power cords are just as good and can hear no differences,I won't tell you that you or your system has a problem.I can only say that I have heard the differences they can make, and some power products can bring out more details than others, which is a good or bad thing depending on where you sit on the fence.

You are you and I am me, we both listen for different reasons and perhaps analyze the sound in different ways.

I would speculate that the folks who are music lovers, first would be most content with the cords that come in the box, because they listen for different reasons than I do.

I was content for years to listen to a purist type system.

Stock cords,no power conditioning etc.

I was happy, I didn't think it could get any better.

It wasn't until I heard some of my music on a different system that I realized all was not right in paradise.

We tend to use our own system as a benchmark, and get very content with the sound it gives us, and we think of it as a "reference".

I've known some music lovers to prefer harmonically distorted systems over more accurate revealing ones.
Terms such as "warmth" come into play.

I don't feel that resolution is a bad thing.

I feel that you can have a highly resolving system and still be enthralled by how natural it sounds.

I think that there are enough natural distortions in the chain from recording to playback as there are,no need to add any more with bad power.

If you like your music wrapped up in a warm blanket because it's easier to listen to,that's fine.

But I know you can still get the warmth without the blanket effect.

Resolution doesn't have to equate with irritable, edgy sound.

For my money,what the extra resolution is revealling is the flaws elsewhere in the chain that need to be addressed but which seldom are,just because you feel certain things shouldn't make a difference.

The reason why so much good sounding gear is traded, is because it's never been given the chance to perform at it's optimum.It seems more reasonable to switch amps every three months than to try a better power cord.

How many times have we seen"spend your money where it will make the biggest difference"?
Hey spending money keeps the economy rolling and we need that,but wasteful spending is much better left for the politicians.

So which is wiser? Spending a few bucks on better power or spending large on new amps and speakers every few months?

How wise is it to use the same stock power cord you used for the last 20 years on every new amp you purchase?

My guess is that by doing so, you'll be looking for another power amp in the next month because the new one just doesn't sound any better than the last one, as all the hype led you to believe it would.Damn those reviewers,must have been bribed.

I've got some pretty old Acoustats with the tube servo amps.

How they sound today with good power cords and conditioning could be compared to more costly speaker/amp combinations and would still hold their own in light of modern "breakthroughs" in technology.At least that's how I hear it.
My previous speakers were quite a bit more money than the Acoustats, and they had some pretty expensive components inside them.
Leaving them and going back in time has not been a disappointment.

I can distinguish the merits of both speakers, they do not sound anything alike.Nor do any of my interconnects.
And good/bad recordings, vinyl or digital are represented as what they are.They are not sugar coated to all sound alike.

I find it odd that some would prefer their entire music collection to have the same "musical" sound.
Sorry, I'll take resolution over homoginized any day.
Better power will let you hear the differences,you have been warned!

Has anyone actually tried hard wiring a good 12 awg chord, bypassing the IEC of an amp or/? just to compare? I haven't seen any feed back regarding this comparison as yet. Maybe a decent shielded computer chord you can pick up for less than 20 bucks?

If you are really interested in the why, the Shunyata website may offer considerable scientific insight into the answer. .Apparently the development of the DTCD analyzer allowed Shunyata to develop it's new power conditioners.Suggested good reading for those with a scientific bent.