Cable Asylum: Why shorter is not better by Caelin Gabriel

Do longer power cords sound better? YES.

So does that mean if you take a stock belden cord and make a 12 foot version that it will sound better than a 6 footer. NO.

How do I know? Because I have done the testing that shows this to be the case. There are a lot of misconceptions about power transmission and power quality that make it difficult for some people to understand why a power cord makes a sonic difference. The first question is - do power cords make any difference at all? There is no sense in talking about theories of operation if we can't agree that there is an audible effect. Most of the thousands of people that use our power cords started out as sceptics and have answered that question for themselves. And no - I do not care to debate with people that have not done the simplest of tests about whether power cords work or not. The only cases where a high quality cord does not have significant effects is when it is used with a poor quality power conditioner that acts as a high impedance to instantaneous current flow.

MIsconception #1:
AC power is like water coming from a large power tank, flowing through several 10s of feet of power hose into a component. This implies that the component is at the end of this system.

Actually, the component sits between two power conductors: the hot and the neutral. AC power oscillates (alternates) back and forth at a 50-60hz rate. So power does not pour into the component at all. The component's power supply is within a complex network of wires and connectors. ALL of the wire and connectors can and do affect the performance of the component's power supply.
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Misconception #2:
AC power can be contaminated just like water in a hose. This implies that once the water is contaminated at some point up stream, that is must be cleansed before it arrives at the audio component.

As stated in #1, the component is not a the end of the power hose. It is between two power hoses and the current is oscillating back and forth. Further, current is not like water at all. Electrons cannot be contaminated. There are two aspects to power transmission: the EM wave and the current flow. The current itself cannot be contaminated but the EM wave can be modulated with other frequencies. We usually call these other frequencies noise or EMI. Within the various parts of a power circuit there may be EMI in certain parts that are not present in others. EM energy can be transformed or redirected to lessen their effects.

Some PCs use capacitors, inductors, or ferrites in an attempt to control the EM fields around the audio component. The success of such an approach is completely dependent upon the specific design and the reactance of the power supply of the component to which the PC is attached.
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Misconception #3:
There is up to a hundred feet of wire in the walls, so the last 6 feet of power cord can't possibly make any difference.

The PC is NOT the last 6 feet as stated in #1 and the local current and EM effects directly affect the sonic performance of the component. The power cord is not the last 6 feet, it is the first 6 feet from the perspective of the component.
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Misconception #4:
There is a tremendous amount of electrical interference and EMI coming from outside the home that we need to protect our equipment from. This implies that we need some sort of power conditioner or filter to protect the equipment.

Most of the EMI that affects the audio quality of a system is generated by the audio components themselves. EM waves that travel through space dissipate in power as the square of the distance from the source and very high frequencies that propogate through the power circuit do not survive for long. Power lines present a high impedance to Mhz and Ghz signals due to the relatively high inductance of power lines.

A primary source of audible sonic degradation is caused by the power supplies. Most components use FWBR (full wave bridge rectifier) power supplies that generate an incredible amount of transiet noise when the rectifiers switch on. The design of a PC cord can significantly affect the reactance of these signals within the power supply. The PC is effectively part of the primary winding of the power transformer. The transition between the various metals used in a PC can cause EM reflections and diode-like rectification of the noise impulses as they propogate away from the power supply. If the PC presents a high impedance to these signals they will be reflected back into the power supply where they will intermodulate increasing the high frequency noise levels of the component. Most power supply filters are ineffective at blocking very high frequency noise components and much of it is passed through to the DC rails. The sonic effects of this include: high background noise levels, blurred or slurred transients and a general lack of clarity and purity of sound.
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Misconception #5:
There is some sort of conspiracy amoung audio designers that keeps them from producing a "proper" power supply that is not affect by PC quality. This concept is like saying that if a speaker where properly designed, you wouldn't need to use a good quality speaker cable.

PowerSnakes have been tested with the most modest of mid-fi equipment and the most exotic SOTA components. We have yet to find a component that cannot be improved by replacing the power cord.

As long as power supply design is based upon FWBRs or switching supplies, the power cord will always be significant.
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Misconception #6:
High-end power cords just increase the circuit capacitance acting as a high-freqency shunt.

There are some power cords that ARE designed this way. Some even insert capacitors within the cable to further increase capacitance. This approach has some positives and many negatives which I won't go into here.

Capacitance alone cannot account for the differences in a power cord's performance. There are some high-end power cords that are very effective that have virtually unmeasurable levels of capacitance. These cable are usually designed around hollow tubes with the conductors inside. The conductors are several inches apart and cannot significantly affect the capacitance of the power circuit.
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MIsconception #7:
Power cords are just like speaker cables; the shorter the cable the better.

Some speaker cable designers would argue that a speaker cable below a certain length is not better. We will let them address the issue if they desire.

A speaker cable conducts an audio signal from the power amplifier to the speaker. The distance is quite small, on the order of a couple of feet to several feet. The quality of a speaker cable is determined by how well it can transmit the signal from the amplifier to the speaker without alteration.

A power cable on the other hand is not transmitting a signal. It is conducting A.C. power and its sonic superiority will be determined by its ability to deliver current (steady-state and instantaneous) and its ability to deal with the EMI effects of the components to which it is attached.

SInce a power cord is composed of a hot and neutral wire that the component sits between, a change in the length of the cord will increase the size of the "buffer" around the component. In the specific case of PowerSnakes - we use a proprietary substance within our cables that absorbs EMI. Increasing the length of the cable, increases the coupling effect to this substance, therefore increasing the performance of the cable.
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In general, I would not recommend a power cord that is shorter than 3 feet or 1 meter in length. But subtle degrees of audio performance are not the only consideration when putting together an audio system. Esthetics are also important especially when the system is located in a beautiful home. I just point out the performance differences so that people can make an informed decision when determining the optimum length for their cables.

There is much more that can be discussed about power delivery but for the sake of brevity I'll cut it short at this point. On a personal note I would like to say that I was an audiophile long before I was a manufacturer of audio products. Before Shunyata Research I designed high speed networking devices and can tell you that there is a lot more money to be made in the computer industry. Like many of the of manufacturers of high-end audio components, I design my products for myself and for the love of music. If other people like what I have created - great. If after trying our product you prefer another - great. There is a wide diversity of preference and subjective perception amoung individuals. Thank goodness there is also a wide diversity of manufacturers that create products to serve a variety of tastes.

Caelin Gabriel
Shunyata Research Inc.