Power cord? Why?


I see a lot of posts regarding power cords. I would like to know what sonic difference they actually make. Could anybody explain this in a simple way?

Thank you
cfmartind362
Fair enough, Twl. First of all, let me say that you are not under attack, and that I think you should be free to decide on whatever products you want to buy based on whatever comparisons you choose to make.

Second, let's be clear about what science is, and is not. No one claims it to be the final truth. It is no more than the best explanation for something, based on everything we know to date.

Third, there are a number of different sciences at play here. Yes there's electrical engineering, and the physics that underlies it. There's also biology (since part of your "system" is your ears) and experimental psychology, which is also a science and operates under the same empirical rules as physics.

I don't know enough EE to say for certain that power cords can never affect the sound. I suspect, but cannot prove, that when they do, there is probably something wrong somewhere else in the system, since it's not terribly difficult or expensive to build a power supply that can handle the normal quirks of residential electric service.

No one claims that, "If we can't measure it, it must be your imagination." But the tendency of people to hear differences between things which are demonstrably identical is a scientifically validated phenomenon. So if you compare two power cords (without the kinds of scientific controls that those who study human hearing use) and conclude that they sound different, the best you can say scientifically is that there MIGHT be an electrical reason, or you MIGHT be falling victim to this "placebo effect."

Of course, the more plausible the electrical explanation you have for something, the less likely it's the placebo effect. The lack of a good electrical explanation (absent, say, some known problem with a power supply) is what leads some of us to suspect that the placebo effect is at work here.

Finally, let me say that "falling victim to the placebo effect" is not a bad thing. It's normal, and no one is immune. (Including me. I once witnessed a demonstration of the infamous green pen effect, and damned if I didn't hear a difference. But under the circumstances in which I heard it, the placebo effect--or a judicious nudge of the volume knob by the salesman who was doing the demonstration--was the most plausible explanation.)

I don't expect you to agree with everything I've written here, so I suppose we'll just have to agree to disagree. But I hope I've made it a little clearer where I and some others are coming from, and maybe that'll help keep the sniping to a minimum, which is something we can all agree on.
Eldartford: Many of your suggestions are valid and are exactly what should be done by those designing / building the gear to begin with. As such, i would have to say that we are probably on the same page / line of thinking, but our actual experiences differ.

Besides that, the ESR of some capacitors at 20 KHz will be MUCH higher than you think it is. Regardless, the ESR doesn't really matter to RFI since the caps are in parallel with the power supply and the RFI can "ride right over the top" of them. You acknowledge this in your post when you mention digital gear "pumping signal" back into the AC lines. After all, such a signal would have had to have either been radiating into all of the circuitry in the box and using the power cord as a feedline OR the circuitry was actually modulating the power supply and feeding signal back into the AC system. Both are distinct possibilities and realities and i think that you know this. That's why i want YOU to experiment on your own and see for yourself just how "under-designed" most of this "high end" gear really is.

Theory aside, your first hand experience will probably change your mind about things. I'm not saying that you will become a power cord convert, but that you may better understand why some people talk about actually hearing sonic differences. The approach that you mentioned i.e. better filtering and design of the power supply, is the right approach in my mind. Reducing the potential for RFI and other "pollution" entering the gear through the use of more technically advanced yet reasonably priced power cords can only help the situation though. Sean
>
Twl: As Audioengr mentioned, some batteries will be better for this than others. As a side note, this is the reason why some car stereo enthusiasts employ LARGE filter caps very near their amps. The caps themselves can discharge and supply power faster than the battery sitting very near it can. This is due to differences in the internal resistance of the devices themselves. While some caps may be worse than some batteries, caution must be used when selecting such a cap. Very careful selection of batteries and placing them very near the device drawing the current may negate the need for any support components such as caps, etc..

I'm curious as to whether or not you've ever tried anything like this ? The main things that i'd look for if you did was greater bass impact with greater punch / clarity on peaks. Sean
>
Sean, I'm currently using a large capacity lead acid automotive battery with 650 cold cranking amps, located about 24 inches from my amplifier. I have the terminals directly connected to the power input barrier strip on the amp, with 12ga OFC copper stranded wire.

I have not tried any capacitors on the power connections as of yet, but the idea has crossed my mind. I was thinking that since my amp only draws 3.1 amps @ 12vdc at rated power, I figured that the 650 cold cranking amp capacity of the battery could handle that. From my listening observations, this amp really has some balls in the bottom end and dynamics, even though that may sound comical with only a 2 watt SET 45 amp. But it really is true. This amp has alot of punch, and it makes those Lowthers stand right up and get with it.

Another thing that I have done, is to use a separate battery for each of my components, so that there is no modulation of the power supply of one component by the draws of the other. This seems to make a difference. Individual power supplies take the idea of "dedicated AC lines" further into the isolation of each components power supply totally from the others. I like the effect of it. It's clean.

I'm still working on doing whatever I can think of to ensure the cleanest, unencumbered power to my components as I can possibly do. I think that the flat DC, with no intermodulation between components, full isolation, and high current availability has improved my sound.