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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 3 responses by sfischer1

sfischer1's avatar
sfischer1
56 posts
 
As an EE I initially chaffed at the notion that a power chord could affect the sound of a piece of equipment because the AC signal is typically rectified and smoothed to DC by capacitors. After being blown away by apparently large improvements in SQ after installing conditioners and wires from Synergistic Research and then Audience, I started to think more about it.

The first point is that my assumption of smoothing by the capacitors is weak. There is always ripple, a saw tooth shaped variation in the DC (not quite) voltage, and sharp current transient spikes replenishing the energy stored in the caps. These spikes are comprised of high frequency components, producing corresponding distorting voltages, which may not be effectively handled (filtered) by the large filter caps which are not ideal and function as intended for low frequencies only. These high frequency signals then bleed through the caps and can then be reflected back and forth between the power source and the amplifier circuitry based on transmission theory. This doesn’t even address the potential noise generated in digital systems that will appear on the signal and power bus of a system. Perhaps power chords and line-conditioning affects these also?

Our problem is that we distill a technical problem down to a simple ohm’s law based steady state small-signal analysis. In reality, power connections are inherently a large signal transient analysis problem which could be analyzed but aren’t. Bottom line is that many of us learn Ohm’s law and think we understand everything and we try to simplify/distill a problem down to fit our analysis abilities. Ironically, I don’t believe that many of the cable producers have great technical insight, but rather, they have a practical insight into what seems to work.
sfischer1's avatar
sfischer1
56 posts
 

If you purchase a power regenerator, I assume you do NOT need a better power cord for the regenerator itself. Yes? Because if takes power, confers to DC before producing ’clean’ AC again, I would guess the power coming in can be as dirty as you like. I don’t know, curious.

@dseltz
The problem with a regenerator will be its’ power capacity. It may work well for smaller loads like preamps but will likely suffer as many problems with larger loads. A regenerator needs to act as an ideal voltage source, meaning near zero output impedance, which means it would show no change in the voltage as currents are generated at its’ output. They are unlikely to be anywhere near as good as a decent AC line. This is why a good AC line conditioner may be more beneficial. Whatever is used should minimally restrict current delivery and should be effective at filtering/cleaning up noise on the AC line.
sfischer1's avatar
sfischer1
56 posts
 

Given the differences are claimed to *audible*, I guess it’s reasonable to assume that sth like noise levels, sound distortions etc must show measureable differences after changing power cord. Curious whether anyone has done that.

@yang_hong
Transient signals are non-repetitive and difficult to measure without constructing sophisticated test signals. We can attempt to measure a broad spectrum of "noise" in a system which should be ideally silent. Even when visible, it may be difficult to correlate how the signal correlated noise will interact with the signal and manifest itself audibly.

I often hear the improvements as a broadening of the stereo presentation or as an increase in the harmonic richness such as is apparent in the sounding board of a piano.

In the end, if it doesn’t give you pleasure to strive for and realize these improvements then don’t worry about it. Competent interconnection is all that’s needed. As I mentioned in my original entry, some folks feel like they understand the world when they obtain a little knowledge and find it unsettling when others express ideas which suggest that their understanding may not be complete. This doesn’t mean that those who believe they hear differences aren’t themselves riddled with biases, usually of the sort that whatever they have is the best or all that is needed by anyone. This isn’t limited to audio. ;)

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