John Dunlavy On "Cable Nonsense"

Well I'm through with this too after a few paragraphs..........

Some things to think about:

Fact: Interconnects are designed to carry low-level audio signals between various audio components by coupling their electronic circuitry together. It makes perfect sense then that interconnects will have an audible effect on the sound of a system. It also makes sense that one could experiment with interconnects to alter the "tone" or "sonic signature" of the system.

Fact: Speaker cables are designed to carry audio signals and should also have an effect on the over all sound of a system (but to a lesser extent than the interconnects which carry a low-level signal that by its very nature is more sensitive to variations in cable vs the high-level signal carried by the speaker cables).

Fact: The AC power cord is designed to carry AC power with sufficient current to the equipment. It is not designed or intented to carry audio signals at all. Additionally, the AC current being fed to the equipment will ultimately be turned into "clean" direct current within the power supply. The intent is to have NO AC signal, audio or otherwise, in the DC power being supplied to power the circuitry.

Fact: The AC wiring in your house behind the power outlet is common and cheap. Unless you rewire your house first, it makes no sense to me to use an outrageously exotic power cord to the equipment.

Back to my original question, "do you believe an AC power cord should be used as a tone control"? I do not.

Abe, It is common practice for a system owner to change interconnects in an attempt to 'produce' the sound he desires. I think you can agree that they can alter the sound. Speaker cables are the same way.

Now to make a point about the lack of quality power cable behind the outlet. I have opened at least a hundred models of audio electronics. I have found very poor quality wire inside the units. I have tried many different cables with these units and have heard differences. I have changed three inches of wire inside a unit and have heard a change. Do you really believe that all high quality electronics and speakers are wired with high quality wire? If hundreds or even thousands say they can hear the difference in speaker cables does that mean they ALL are listening to speakers that are wired with high quality wire inside? I think not.

Our ears have the ability to distinguish differences that the audio community has now figured out how to measure. I was trained in the precision measurement field of electronics. I understand the current forms of measurement pretty well and we are not even close to making measurements that can tell us what a piece of equipment sounds like. As an example of just how foolish a measurement means to audio, consider this. A normal low frequency speaker will easily produce over 1/2% distortion. Then how is it we can tell a difference in the bass performance of loudspeaker cables. The cables do not produce more than 1/100 of the distortion of the speaker.

Now on to the topic of AC power. If we use a similar analogy to the power cable it stands to reason that even a few inches of wire could make a difference. I agree that it could be even more important if the wire behind the outlet is high quality. (I believe it enough to have rewired my house with the stereo in mind) It is false to assume that the AC to DC converter (the power supply) is not effected by what comes in the power line. Our equipment is connected to the power grid. That power grid stretches all over the country and every minute of every day lightning is hitting the grid. Heavy machinery is dumping transients on the grid every second. It is imperative that this noise does not get onto the DC buss inside our equipment. It is next to imposable to stop a transient from passing thru the diodes and dumping a charge onto the filter caps. I believe that power line filters are our first line of defense to this grunge. Who is to say that a power cord does not have some property that helps in filtering this trash and keeps it out of our systems?

And to answer your question: YES I believe a AC power cord, just like a speaker, cable can be selected to 'adjust' the sound to one's liking. Most people feel that a tone control can be used to 'adjust' the sound and so therefore a cable is a form of tone control.

Chris

Chris, I agree with much of what you said and you put a lot of calm methodical reason behind your comments.

You talk about mating high quality speaker cable with speakers that do not necessarily have the highest quality wiring inside. While people may hear an improvement in the sound (I have), at least here, we are making the adjustment in the *audio* path where you get more "bang for the buck", if you will. Possibly more so with interconnects.

We both know that the AC power cord is not in the *audio* signal path at all so I still have an issue with making adjustments here. On top of that, most of us have several hundred feet of copper wiring at a few cents per foot behind our power outlets yet some people are willing to spend a hundred dollars or more per foot for say, a 6 or 8 foot run of AC power cord (that plugs into several hundred feet of cheap copper Romex). You upgraded your house wiring but I'm sure that most of us have not.

I can understand using a power conditioner or filters on the AC line and many components include a little filtering where the power cord enters the chassis. I think we both agree that this is filtering to reduce "grunge" on the AC line and not for altering the tone of the system. And beyond that, there's the stiff power supply regulators and filter caps.

Maybe its just me but I still think the AC power cord is the least effective place to make tonal adjustments to the sound of an hifi audio sytem. I believe that an AC power cord of sufficient wire gauge to handle the current draw is more than adequate and any adjustments in the sound of the system should be done either in the transducers, the electronics, or the audio signal path between components.

I guess I'm the only one but this is my opinion. I'll leave it at that and let it go. Cheers!

I vote let's try my question for a while, it's more fun to think about and makes about as much sense. Here it is: Who-let-the-dogs-out?

Abe, I really do agree with you 100%. It does seem silly to spend dollars a foot on power cables when the Romex is roughly 10 cents a foot. I do not plan on spending my stereo allocation for the next six months on a power cable. Because of my electronics and electrical background, I will make my own. I started out by putting a heavier gage cord on my power amp. It helped, but I did not go farther with power cords because, like you, I felt that size was the issue.

I then got introduced to this and other forums, and all the talk about hospital grade outlets. I had a friend tell me about a hospital grade power cord. He sent me one and I compared it to a shielded IEC cord I had found. Both cords were a lot better than a standard computer cord. They both were even better than the heavy gage cord. The shielded cord had a ferrite 'bead' and may have been responsible for the lower noise floor and better focus of the images. I do not have the answers. I wish I knew what it is that makes a power cord change the sound.

I think we all can agree that a filter of any sort on the power line can have a positive effect on removing high frequency transients from the AC power. I have three filters in series on my power amp! I feel that it is possible that some of the high end cords might, because of their geometry, have special filtering capability. This could be at ultra high frequencies where the mutual capacitance of a big heavy inductor in an after market noise filter just passes it through, but the cord stops it.

My experience in industrial electronics has educated me to the hazards of a poor electrical connection. I have seen the results of a loose connection on a motor. The motor overheated from the reduced voltage and melted the insulation on the windings. Every connection in our systems can be a source for problems. Heavy current flow into the power amp could easily be restricted by a less than perfect connection on an outlet or cord. I had to put a slow turn on circuit in my amp to prevent blowing the 20 amp breaker in the distribution panel! I know that a magnetic circuit breaker can pass many times its rated current for a short transient before it will trip. My amp was likely trying to draw over 60 amps at powerup. Some will not believe that 12 gage wire can supply that much transient current. I know it to be true! I wired a 12 gage 100+ foot circuit going to a pump wrong and when I applied power to the pump it popped a 100 amp fuse instantly. Those little 12 gage wires handled in excess of 100 amps and did not melt or even burn the insulation.

The point that I am trying to make is that I feel we do not understand all the interactions that affect the sound of a system. My ranting(s) are for the purpose of shedding a little light on areas that may affect what we hear. I am sure that many 'discoveries' are waiting to be exposed. I know that discussions like this stimulates me to look deeper for a possible answer. I look forward to more discussion on this topic. Ideas or questions placed on this forum can be the spark that sheds light on a new understanding. I am certainly ready to uncover some of the *snake oil* in the high priced cables so that the less finically fortunate can afford good sounding cables.

Chris