I finally learned why powercords make a difference


While sitting for many hours at the CES together with Mr. Strassner of HMS I took the opportunity to ask him the question which seems of importance for most audiophiles:
Why do power cords make a difference? Or in other words: Is it really important to spend a considerable amount of money on the last 6 ft in the form of power cords, if you have hundreds of feet of inferior cable running inside the wall? So why would a 6 ft power cord justify the expense.
Because I want even to give the audiophile layman a chance to understand why it indeed does make a difference to use a good after market power cord and why this investment is justified, I will use a rather simple language and explanation. The real problem is a bit more complicated of course.

There are two things a power cord has to take care of:

Low frequency distortions,
High frequency distortions

Low frequency distortions:

I assume it is a known fact that all components have to be fed from one common source (or having one common potential) to avoid a so called voltage differential, which will cause distortion. So since all components are either fed from a common wall plug or a power wing or powerstrip with 6 or more outlets, there is almost no voltage differential going on inside the wall, since all is going on the same potential, inside one cable.
The key to understanding the issue is that as soon as you have a voltage differential between components, you will have currents running through the interconnects, which connect the components, trying to equalize the voltage differential, trying to bring it to zero. These equalizing currents cause low frequency interferences, which will harm the sound. Now inside the wall you have no voltage differential, since all components are fed through the same source.
But once you connect your two or more components with power cords, you start to have different voltage drops on each single power cord, since now the one cable (your inside wall cabling) is branching into two or more lines (at the powerstrip of course) to feed your components. This results in a voltage difference between the components.
There is also a resistance between each power cord plug and the sockets of the powerstrip and the components of course use their voltage needs not at the very split second, but have a different current demand. So all of this is now causing a voltage differential inside your components and since the law of physics dictate that this voltage differential has to be brought to zero, equalizing currents start to flow between the components, through the interconnects. So you can easily imagine that these currents will harm the musical signal, so power cords have to be built with a low ohm and inductive resistance to bring down these currents as low as possible.
This is the first reason, why audiophile components need good power cords.
But we do not only have low frequencies, which have to be addressed by power cord builders. There are also two sources of high frequencies distortion, but is seems that most power cord companies have failed to address this important issue:
The first reason is that each power cord will always act as an antenna, picking up all sorts of high frequency signals, from your neighbors computers to cellular phone or radio signals. And this pollution of high frequency signals will only get worse in the future.
So here you need several filter elements, which will let you filter out these distortions. A passive version is just not very efficient.
But there is another culprit for high frequency distortion, ruining your audio signal. These are high frequency signals caused by the very audiophile components you use. These interferences, (whose end product is ringing or distortion) are either caused by your CD player, or by your amplifiers, since they do not have a steady power demand, but pulsate, since the power demand varies according to the dynamics of the music.
So in very simple terms, this pulsating of the power supply of your amps will also cause high frequency interferences, which are being fed back into the system, harming and ruining the musical signal. This is a serious problem and you will need a filter solution to rid your system of these problems.
So in very simple terms above mentioned problems have to be addressed by your power cord and the better a power cord can handle all three problems at the same time, the better your system will sound.
So these are the reasons why good power cords, are extremely important in a good audiophile system.
tekunda

Showing 2 responses by aball

From an electrical engineering standpoint, there a few problems with the arguments.

First, lowering cord resistance does not lower the currents. On the contrary, it would increase them according to Ohm's Law since you state the voltage differential is between the amp and outlet - surely an error in logic here. Second, for the cords to eliminate the differential voltages, there would have to be a special LC filter involved that dissipates to ground - which is not the case since a cord is a cord (however, perhaps MITs do?). Third, if the power supply is any good, the differential voltages will be miniscule anyway and the error will be taken out of the amps, and not the cords, since they are the only ones that can sink the difference effectively. Thus, the cord does nothing to help here either.

The biggest effect a cord can have is shielding (and definately not filtering as the argument states) from EMI which is present for sure in bad power supplies. I beg to differ with the cord designer but he is also a business man. I am an electrical engineer that deals with these sorts of things daily doing research on high-power power supplies and so have to be very sensitive to these things. The cords don't do much but shield as I said above. This may account for the sound differences people hear, and then again, it may be psychological (I am dodging the tomatoes ;).

There will be differing opinions on this but mine is strictly from a technical viewpoint. I can fill in with great detail for those who wish to email me privately about it. Arthur
For the record, English is not my native language either but I think we understand each other well enough....

I am anxious to hear all about it from Herr Strassner himself.