I could always understand why interconnects in an audio system could make a difference. We are talking about very low-level signals, which can be easily influenced by the electrical characteristics of the wiring. Resistance, capacitance, and even inductance play a part, not to mention shielding to reject noise.
In speaker cables, size matters–there are measurable losses, based on the amount of power a cable is handling. Larger gauge speaker cables have less resistance than smaller cables, resistance turning that sound energy into heat, which is a loss of power. If you ever want to experiment, go out and buy the absolute cheapest and thinnest speaker wire you can find, and substitute it in a good system. Even a non-audiophile can hear the difference.
But, what about power cables? This is where I start becoming the skeptic.
It’s true that a larger gauge power cable will allow more power to an amplifier without loss. But beyond that, what sort of snake oil is at play here? I know an audiophile who makes his own power cords from heavy gauge, rubber-jacketed cable you can buy at any large home improvement store, with good quality connectors on either end. And his system is one of the best I’ve heard, including some of the most holographic imaging I’ve heard in an audiophile system. He uses these cables on both his power amplifiers, his preamps and his sources.
But what is there for me to be skeptical of? Why are his relatively inexpensive cables so capable of providing such a good end results, such that a $1,500 power cable looks like a ridiculous purchase? Let me break it down into the finer details.
Consider the following. For low-level components, I could see an advantage to a power cable which might have some sort of shielding to it. If it can bleed off stray EMI/RFI before it gets inside the component, that could be an advantage right there. But as for the type of conductor…well, that doesn’t quite fly with me. We’ll see why in a moment.
A power cable for a source component or preamp need not be some huge conductor either–it can be, but due to the amount of power passing through it, anything much larger than needed is a waste.
Let’s get down to the basics.
First of all, where does our power come from? A power plant. Likely dozens of miles away. It passes through miles upon miles of cabling, and many transformers along the way. Consider this electrical fact: a length of wire can more easily carry voltage (a difference in potential–the official definition) than it can carry current. That is why voltage is delivered to the neighborhood as high as tens of thousands of volts, and transformers on the poles knock that down in various ways to the 120 volt/240 volt electricity we receive in our homes.
Within the home, the electricity enters via a service line, which connects to a circuit breaker panel. From there, the electricity goes through one circuit breaker for each circuit in the home. In the US, the electrical code calls for 14 gauge cabling for 15 amp circuits, and 12 gauge for 20 amp circuits. Common electrical wiring is often called “Romex,” and is a trio of solid copper conductors: one hot, one neutral, and one a grounding wire.
Where does this wiring go? It starts at the breaker panel and goes to one outlet. Which is connected to another. And then another. That same circuit might also head up to the ceiling to power some overhead lighting. Most circuits in a home have a series of outlets that are daisy-chained together, whether they be wall plugs, lighting, or other lines. Some major appliances have their own dedicated circuits (ovens, electric dryers, central air conditioning units). For all others, it would be highly impractical, not to mention very expensive, to run an individual run of Romex to each individual outlet or lighting fixture in a home.
Those wall outlets in your listening room may be at the very end of one of those daisy-chains.
Every inch of Romex is a tiny loss of power. Each connection point along the way is also a loss, and a point of failure. Our outlets in the listening room could be a few feet from the circuit breaker, or could be as many as 50 or more feet away, depending on how many other outlets the same circuit is feeding.
And on the end of all this mayhem, we want to slap a $600 power cable??
Many audiophiles are able to run dedicated lines to their listening rooms, which is great! If I could, I would run 10 gauge Romex to my listening room, directly from the breaker panel. Not everybody has that luxury, though. Even so, we’re talking about power that has traveled miles outside of our home, and many feet (or meters) inside the home…and applying something expensive to only a very tiny portion of that.
Silly, isn’t it?
Now, one last point. Audio Research, the manufacturer of high-end preamplifiers and power amplifiers, recommends using the power cables provided with their equipment. Supposedly the claim is that they have heard no benefit to changing (notice I didn’t say “upgrading”) the power cable. Why is that?
The power coming into our homes (at least in the US) is 60 Hz AC. Pretty much a sine wave. It isn’t perfect, and it picks up all sorts of EMI/RFI along the way. Yet, it is what it is. Just about every component you own has a power supply section whose only task is to turn that 120 volts of AC (alternating current) into a constant and clean DC (direct current) power source.
Inside your power supply, the AC passes through a transformer to reduce (or sometimes increase) its voltage. It then passes through a full-wave bridge rectifier to “flip” the sine wave around. Capacitors smooth out these “half sine waves”, and the higher the capacitance, the better. (Capacitors are able to store energy, hence the ability to smooth out AC voltage.) From there, the power often enters a voltage regulator or at the very least, passes through a zener diode circuit to maintain a constant output voltage; if the input voltage dips, the regulator increases its output to keep the voltage steady. Additional capacitors and inductors (coils) are often used to filter out any additional noise and “garbage” that might pass through.
It goes without saying that a better designed power supply will provide the most pure DC output, the ideal being the constant voltage a battery would produce.
So, if all of this cruddy power coming into your component is so nicely filtered by its own internal power supply, why would a $1,000 power cable have any difference in sound from a throwaway $5 computer cable for, say, a source component that only draws a few watts? Or, why would a home-brew power cable with 8 gauge strands not be any less a cable than a $600 power cable others might sell for a power amplifier?
It shouldn’t make a difference. The power supply does the job of cleaning up the sound. I can see, as I mentioned earlier, where some sort of shielding to bleed off stray EMI/RFI would help–it reduces the work that the power supply has to do to clean up that power. But aside from the “crud,” the only thing coming through a power cable is a 60 Hz AC signal of 120 volts! That’s it. No rocket science. No magic. Except for electric AC motors (which rely on the 60Hz frequency to determine their rotational speed), the power supply does not care what it gets.
This does, however, make me wonder about how well, or how poorly, power supplies can be designed. Audio Research is confident enough to say that the power cables make no difference, making me think their power supplies have been adequately designed to handle any type of “garbage” that comes across the power line, to the point that it does not adversely affect the audio output.
My thoughts on this? Putting a pricey power cable on a very tiny fraction of the entire link to the power station is not doing anything at all. That wiring in your home is probably the cheapest the contractor could buy at the time. The wiring outside the home is designed most for durability. And we’re fussing over several hundred dollars to put some “bling” onto the end of all that?
I would also say that if there is a difference due to “crud” in the incoming power (EMI and RFI), that the component in question has a rather poorly designed power supply which can’t properly handle cleaning up that power. The power cable in this case is reduced to the role an expensive Band-Aid to correct a component’s shortcomings.
I’ll leave it at this point for now. When you look at the facts of 120 volt AC power coming into your home, expensive power cables make no sense whatsoever. Whether it’s audible is up to what a person wants to hear, I guess.
For a power amplifier, I would say that using an 8 gauge power cord is as safe as it gets. At worst, you should match what is in your walls–likely 14 gauge, sometime 12 gauge. Should you ever rewire your listening room with 10 gauge wiring, that 8 gauge power cord still has more capacity, so it is good for future growth. Cabling larger than 8 gauge gets unwieldy. I’m not saying this size is a cure-all, but if you are the type to want to do things once, the right way, pick one size of power cable that will handle your system’s capabilities now and in the future.
As for source components? Sure, you can upgrade a bit from that stock cable that came with your component, but don’t go overboard. Better connectors and wire of a known size and quality can only help. Yet you can get that in a power cable under $100 or considerably less. After hearing home-brew power cables in a system that surpassed most others I’ve heard, I can’t say I’d be missing anything by avoiding the high-priced “bling.”