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Why Power Cables Affect Sound

I just bought a new CD player and was underwhelmed with it compared to my cheaper, lower quality CD player. That’s when it hit me that my cheaper CD player is using an upgraded power cable. When I put an upgraded power cable on my new CD player, the sound was instantly transformed: the treble was tamed, the music was more dynamic and lifelike, and overall more musical. 

This got me thinking as to how in the world a power cable can affect sound. I want to hear all of your ideas. Here’s one of my ideas:

I have heard from many sources that a good power cable is made of multiple gauge conductors from large gauge to small gauge. The electrons in a power cable are like a train with each electron acting as a train car. When a treble note is played, for example, the small gauge wires can react quickly because that “train” has much less mass than a large gauge conductor. If you only had one large gauge conductor, you would need to accelerate a very large train for a small, quick treble note, and this leads to poor dynamics. A similar analogy might be water in a pipe. A small pipe can react much quicker to higher frequencies than a large pipe due to the decreased mass/momentum of the water in the pipe. 

That’s one of my ideas. Now I want to hear your thoughts and have a general discussion of why power cables matter. 

If you don’t think power cables matter at all, please refrain from derailing the conversation with antagonism. There a time and place for that but not in this thread please. 
mkgus

Showing 6 responses by jtucker

jtucker
87 posts
 
Against my better judgment, I am going to jump in here.  First off let me state that the stock power cables in my system have been replaced, but not with what any of you would consider "audiophile" PCs, just heavy duty equipment grade IEC cables.
There appear to be two ways to look at this, either as the PC being the last few feet of the delivery (looking into the component) or the first few feet (looking back out from the component.  Looking in, a well designed power supply should filter out any unwanted ripple or noise and looking out should prevent any unwanted ripple or EMI effects from going out to the hose wiring through the PC.  Equipment must pass the relevant EMI standards (FCC class B, etc)  It would be possible to measure the differences in conducted EMI using different PCs
Looking into the system, there are also relevant specifications that can be measured, such as PSRR (power supply rejection ratio), transient response and spectral content.  I am not saying one way or the other whether any of this is audible or not, but it would still be interesting to see if there is any real, measurable differences in performance between a standard IEC PC and an aftermarket high end cable.

I have access to extensive lab equipment and a shielded EMI chamber with conditioned AC source. Anyone in the DFW area interested in doing some comparison testing (you will have to supply the after market cable)?
jtucker
87 posts
 
Like I said, I'm not saying one way or the other whether you can hear a difference or not.  Just curious to see if there are any measurable differences, even very subtle ones.  Anyone else?
jtucker
87 posts
 
We have test equipment that can measure small differences in impedance and no they are not inexpensive.  My inquiry is not so much about the impedance of PCs but rather is there measurable difference in the quality of the plus and minus dc power rails of the end equipment or a measurable difference in the ac line (EMI) due between stock and aftermarket PC cables (looking in or looking out relative to the end equipment).  At this point, I don't even want to say whether or not it makes an audible difference.  I just want to know if it makes a measurable difference.  If you can see that there is a measurable change in noise / ripple /  EMI ( or some other quality ) then it follows that you  (may or may not) be able to hear it.  I think it would be interesting to do a comparison between a stock cable and an aftermarket cable under controlled conditions.  I am an EE that has worked in power for many years (disclaimer, not ac but dc/dc converters).  If there is an audible difference, there should be a measurable difference ( and yes I agree that it may be possible that we don't know how to measure that difference yet ).  Anyway , it would be interesting to me at least to look at the obvious characteristics like conducted EMI and PSRR.  Those differences would be easily explainable.  If there is anyone in the DFW area that is interested in doing some real (and unbaised) testing let me know.
jtucker
87 posts
 
Elizabeth,Not necessarily disagreeing with you.  We might not be measuring the right characteristic that may or may not affect the perceived change in sound.  But why not measure the obvious things that most likely could affect sound?  If there was a measurable difference in ripple, noise, EMI or transient response, then that could put the naysayers to rest permanently.  If there is no measurable change, then you may be correct, we are just not looking in the right place.  If there is an audible difference, you should be able to measure some parameter, the trick may be in knowing what to look for.  Or maybe there is no difference...I'm not making any judgement on that one way or the other at this point.  I can't see why it would hurt to at least check some of the obvious characteristics.
jtucker
87 posts
 
@doitwithlife, Now we are getting somewhere.  Difference in both input and output waveforms?  The power cable is between the wall and the regenerator?  Is it possible to share the waveforms?  I would love to get a look.
jtucker
87 posts
 
@doitwithlife, Thank you.  And the first picture is the upgrade and second id stock, correct?  P.S.  Nice system...
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