Power cords cannot make a "sonic" difference because they make no sound. Any difference must be electronic, subsequently converted to sonic by amplifier circuitry and loudspeakers.
Electronic characteristics, unlike sound quality, is easily measured by objective instrumentation. I will not believe that power cords make any difference until someone shows me the data.
And anyway...your line cord is about 6 feet long. How about the miles of wire that the power travels before it gets to your power cord?
If you are interested, I have a bridge in Brooklyn... |
fatparrot...If you read my comment you will note that I did not say that special power cords can make no difference. I simply remarked that the difference, if any, would be of an electrical nature and therefore able to be objectively measured. I am a scientist: like the ones who disproved the subjective opinion that the earth must be flat. Show me the data about power cords. I am anxious to be enlightened.
And Pbb...sorry, the bridge has been sold. |
There has long been "discussion" about whether psychic (mind reading) powers exist. Many experiments have been done using valid statistical methods to see if a subject is doing better than guessing about things like a selected playing card. Results are inconclusive. However, if one scientist could find the MECHANISM for psychic power, perhaps some kind of electrical wave traveling between people's brains, all the sceptics would be converted.
So too about power cords. The reason to look for the electrical characteristics responsible for sonic characteristics is to fix the problem. Thousand dollar power cords may not the the best solution.
Of course the 115VAC power lines also carry some HF modulation...simple table radios often use their power cord as the FM antenna. It's doubtful that any such HF would get through the power transformer impedance, and if it did it would be shunted to ground by the power supply capacitors. What's the impedance of 20,000 mfd at 20KC? Ziltch. If this isn't enough, put some ferrite beads on the power input wires.
If your digital electronics GENERATES noise that propogates through shared power lines to other components you need a better digital electronics design. Fix the problem at the source. (Frankly, if I were digital noise I would travel by the signal interconnections).
What is a "closed mind". I think it is one that dogmaticly argues for some point of view as an article of FAITH rather than as a result of LOGIC. For some, I guess, audio is a religion. |
Sean...OK, here is a test that will be easy to do.
1. Get 2 monoblock power amps (I have a pair of Kenwood LO7Ms which should suffice).
2. Get 2 "super" power cords. (The Kenwoods will need modification to use them. The original cords are, I admit, crummy. Strange for such a well made piece of equipment. (Maybe they properly designed the power supply!)
3. Using the super cords, play the same music signal into both amplifiers. Adjust gain so as to minimize the voltage difference between the HI outputs of the two amps. If everything was perfect this voltage would be zero.
4. Record the voltage. If possible I will use a 100sps bench type precision A/D. With this type of data I can make plots and even perform Fourier analysis of the signal.
5. Now, replace one power cord with a "crummy" one.
6. Repeat the test procedure.
If the differential signal is the same as before, the "crummy" power cord has no effect. Note that while this test procedure does not involve subjective evaluation of sound, it does examine the amplifier audio output that drives the speaker, which is closer to a listening test than measurements of power supply voltages.
Now...what should I use as the "super" power cord. Please suggest wire type and configuration(s). Any other comments/suggestions are welcome. |
sean and others...
1. About the A/D. Of course I meant 100K samples/second.
2. The amp load will be Magnepan MG1.6 speakers, 4ohms ,and with impedance characteristics like a dummy load. (Of course I will listen, but that is not part of my test plan).
3. The input signal will be real music, of various spectral characteristics. I find that real music works best for most things like setting speaker levels, and subwoofer gain and phase.
4. I thought that my initial setup measurements using two super cords provided the reference for comparison. Of course I could do it with the original cords as well.
5. Some of you guys didn't understand the objective of my test. I am not (at this time) evaluating audio quality. I am testing to see if the electrical signal applied to the speaker changes in any way when the power cord is replaced. If it does, then listening tests would be in order. (And I will apoligize to all those I have offended). Viridian..I agree with you about listening being the best test of sonic quality, but I just don't want to fool myself, which is easy to do. If there is no change, listening tests might be fun but can prove nothing).
My speakers only "know" about what comes in to them as an electrical signal from the power amp. Maybe your speakers have psychic powers and can discern the type of power cord in use. That's too far out for me.
6. By the way, when I said that the original power cords were "crummy" I really meant it. They don't even have a 3prong (grounded) plug...but maybe that was by design. I will need to try the super cord with and without ground.
7. The Kenwood LO7Ms may be old, but they were top rated by T.A.S and Stereophile. They are comparable to the best available today. (Besides they are what I have on hand. If you have Krells, or the like, feel free to use my procedure).
8. One procedural detail...I will make the electrical hookup such that I can switch cords without shutting down power, or interrupting the signal measurement process.
9. Hey this could be a money-maker! If I find a power cord effect I can sell the data to power cord manufacturers. If not, they can pay me to keep it under wraps.
10. Finally...(for now)...how about some suggestions about the design of the super power cord(s). |
I bet that someone buys them! |
sean...Thanks for the design spec on the power cord. Based on your suggestion,I intend to use so called "high temperature" wire (intended for range hoods and oil burners) which has very thin insulation. It is readily available. I could use magnet wire, with super-thin enamel insulation, but that would probably be going too far. Three questions...
1. How do I keep the wires "stacked" as I twist them? Does it really matter as long as all four get twisted together?
2. How many twists per foot? (I won't pull your leg about whether the twists are clockwise or counterclockwise).
3. Would not three pairs be as good or better than 2 pairs? I might do this if I can't get #14 wire.
I disagree with audioengr about difficulty of making measurements across bridged amps. Been there, done that. Also, the greater voltage drop in a wimpy power cord does not translate into degraded sound provided that the power supply is robust. As Iasi notes, most power amps play on for several seconds even if you pull the plug completely. I shifted the focus of my investigation from the DC power to the amplifier output signal in answer to those who claim to hear things that can't be measured. The amp output is as close to the sound as we can get without subjective judgements about subtle effects (if any).
As to power cord effect on a CD player...I can try that too. Frankly a CD player draws so little current at such a uniform level that it's even harder to see how a power cord could have an effect. If the display was dim with the old cord it really must have been defective. But then again, this is French engineering. Did you ever work on a Renault?
Regarding Kenwood LO7M...I thought that the LO9M was the lower power unit. The TAS and Stereophile reviews that I recall were before those mags took advertising, and the reviews were credible. My personal review is that these amps, within their 150 watt (8 ohm) power rating, sound darned good. |
Audioengr.... OK. Where do I buy #14 hookup wire?
By the way, why does the power cord have to be "audio quality"? It only has to pass 60Hz. Besides, audio is AC, and the power gets rectified, so any "audio" characteristics of the AC get lost. |
sean....Aw shucks. I am just beginning to get interested in this PC thing. Since the original Kenwood PC are so "crummy" I won't be wasting my time replacing them, and I will do it with multiconductor configuration that you suggest. I checked out listings for power cords, (I need 2) and it seems that your idea of a few bucks is different from mine.
If I can figure out how to send you an attachment (test plan with diagrams) with EMail I will doi it.
Thanks for your constructive comments. |
Audioengr...I will check out your source for large gage hookup wire, and will use it if possible.
On a slightly different matter...I have heard a million times about the wonderful effect of "oxygen-free copper", but I don't recall any explanation of why ordinary copper is a problem. Can you tell us? |
S23chang...Voltage drop aside (because that depends on how long the wire is) 12 gage wire is acceptable (building codewise) for circuits that draw 20 amps CONTINIOUSLY. This is based on the wire not getting too hot. It will actually carry much higher current, and even the 20 amp fuse or breaker that the 12 gage wire is supposed to have will carry 30 amps for quite a few seconds...and longer if it is a slow-blow or time delay type. |
sean...I don't think that I need such a good power cord now that I am operating on my cold fusion electric generator. |
sean...the wire has been twisted...six strands of #12, solid core, thin teflon insulation, with heavy duty plug on the end. It may be a while until I get the test run. When it happens I will report results in a new post. |
sean...3 Hot, 3 Neutral, stacked and twisted as a stack. I am using a 3 prong plug and I have a ground wire connected, but since the original design had no ground wire on the power line (there is a separate grounding lug on the chassis) this conductor is not integrated with the other six. |
sean...what do you mean "staggered"?
My "stack" is HOT/NEUT/HOT/NEUT/HOT/NEUT/ |
sean...When twisted together three #12 conductors were obviously too big to fit even a heavy duty connector. No problem. I soldered the twisted triad together, and then milled it down with a grinder so as to just barely fit the connector. |
Corona...What I milled down was a 3/4 inch length of twisted-together and soldered triad of #20. I would guess this was about #6 in diameter. About 1/2 inch of this I milled down so it would just barely fit into my heavy duty connector...about #10 size.
Sean...Do we have any impedance or capacitance data for the various highly-touted power cords? If not, I don't see any use for such measurements on my supercord.
To all....If you are a Wizard, and are publishing the recipe for a magic potion it is always a good idea to include some ingredient that is difficult or impossible to obtain. (The eye of a newt collected during a solar eclipse on a Tuesday). Then if the damsel does not respond as expected, you can always tell your client that the potion was not prepared properly. This power cord stuff involves a lot of black magic. Are you wizards? |
