That is merely a coded form of "I don't understand EM so therefore nobody understands EM".Max Headroom said:
As I have said before, for analogue audio cable to be directional something in the cable would need to be able to sense both current and voltage and combine them, then inject the result back into the cable with sufficient magnitude that it can produce a noticeable effect in what is the series arm of a fairly trivial potential divider. It would be hard to do this deliberately; even less likely to happen accidentally.
No, cable directivity was not shown. It was assumed by you based on an experiment that was not designed properly to take into account the level of confounding effects.
This understanding is trivially understood by those who design and use nanovoltmeters as well as thermocouple instrument manufacturers and users.
You were also bit by the ground loops you formed.
Ed, you need to realize, failure of a well documented and repeatable experiment is just as important as a successful result. Many non research types such as yourself tend to consider failure of your experiment as bad, and that is not the case.
I thank you for the effort, and encourage you to continue (I'm sure you would do that regardless of what I say
. )But all you are seeing is bog standard shield loop effects and some peltier/see beck stuff. No more, no less.
Jn
Do any of us fully understand energy transfer and matter interactions ?.
The answer is of course no, not yet.
My italics.
It happens automatically, all of the time.
Dan.
Agreed, completely. If I put the same cable once terminated with BNC connectors and second with RCA connectors, one can immediately see inductive spike in the CH2 (red trace). The problem of RCA (not speaking about dimensional tolerances) is that shield is connected to the RCA body in one point, though for crimped BNC the contact is along the whole circle. Even the expensive WBT RCA connectors are not much better than a boutique s..t. If anyone wanted to doubt this, I surely have plenty of measurements confirming this fact.
Audio is mostly about opinions, unfortunately. Almost no one is bringing evidence in measurements supporting their opinions. Rather methods like trial/error or deductions based on influencing secondary issues and not going to the point. So is audio. It is a hobby for most, so who cares and who would wonder it goes this way. You read that batteries improved sound and findings like this. Of course, if the tester does not understand the nature and source of the issue, then he uses band-aids.
That does not change the fact that some (I can't remember how old now) thesis you read and ran with was wrong. As you say, you are entitled to your opinions.
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Define "fully". Otherwise you are merely trotting out the old pseudo-argument "nobody fully understands it, therefore any claim I make however silly and unsupported by evidence cannot be rebutted and therefore must be true".Max Headroom said:
I don't know whether a pink unicorn ever appears at the bottom of my garden, because I do not sit looking at my garden all day. Therefore I cannot prove that such a creature does not appear when I am not looking. Some would take this as evidence that pink unicorns do appear; others would merely create FUD by asking "does anyone have proof that they do not appear?".
Your italics are wrong, because I never mentioned "stored energy". "Stored energy" seems to be the usual fallback phenomenon when some physical effect is claimed for which there is little or no evidence, or no estimated magnitude.
And easier to move a mountain than to change opinions or crappy connectors used as "the standard" in audio.
Cool it, I believe that something is manufacturers cutting one corner too many. Dan's opinion reflects his experience with his market being price sensitive. I can tell because my market is way worse, quality of widely available products are nowhere near those available in England.
I had made a bunch of small PC Cards that were nothing but a bunch of two connected pads and the soldered in jumpers using different solders.
JN,
Your ground loop theory doesn't hold water. Different cables behave differently and the ground path always is the same.
Different cables show different results.
BTY the RF guys do use network analyzers to often see directional effects.
The conclusion I thought was obvious, don't use gear that runs at unusually low signal levels into very high impedances. None of the issues show up at pro levels into 600 ohms or even 10,000 ohm loads.
JN,
Your ground loop theory doesn't hold water. Different cables behave differently and the ground path always is the same.
Different cables show different results.
BTY the RF guys do use network analyzers to often see directional effects.
The conclusion I thought was obvious, don't use gear that runs at unusually low signal levels into very high impedances. None of the issues show up at pro levels into 600 ohms or even 10,000 ohm loads.
"RF guy" here...
You do routinely find this problem. Keeping the center conductor of a coaxial cable pretty much exactly in the center of the shield along the entire length of the cable is pretty hard. There's manufacturing tolerances and the effects of mechanical stress during use.
So, while the impedance might be 50.00000 Ohms at one point of the cable, two feet further down it might be 50.7 Ohms. This tolerance is even specified by the manufacturer.
This is why real measurement cables cost (almost) as much as the crazy audio interconnect cables. They are built to tight tolerances and are really rugged. You still have to toss them out after a while if you're making very close measurements due to the effect of repeated flexing, not to mention connector wear.
Now, I cannot tell you that these same effects make a difference with audio. I plain don't know.
(BTW, it's possible to measure IMD caused by connectors at RF. Another subject.)
They also don't show up measuring mV/femto amp levels with a 10^15 Ohm input electrometers. When you are measuring nanovolts touching the connector will heat it up and you have to wait sometimes minutes for stable measurements. Physicists have been using ultra-high input impedance instruments to measure small signals all the time, I have seen no mention of any issues not explainable.
Ed, thanks for the further input. I should have remembered that you had specified that it was the CABLE assy that had directional characteristics, rather than just the wire. Of course, wire is usually made in a directional way, and I bet this can be even seen at a molecular level in the crystal structure.
In truth there are many effects in metals that are at such a low level that most people overlook them. Break-in of metals actually has been noted with an electron microscope and it is understood by physicists. It is just that some people here just hate the idea that a more evolved product might actually measure or sound differently from a basic product.
In truth there are many effects in metals that are at such a low level that most people overlook them. Break-in of metals actually has been noted with an electron microscope and it is understood by physicists. It is just that some people here just hate the idea that a more evolved product might actually measure or sound differently from a basic product.
Audio design has always been more than just the typical rules of engineering, because what we are striving for has to be acceptable to our ears, not just our meters or even graphical display. It looks easy from the outside, because it is so easy to get some usually acceptable audio from even a piece of junk. Not great audio, but just something that reminds you of real speech or music. We are a nation who listens to our iphones most of the time. However, virtually transparent audio is very difficult, almost impossible to achieve, but we try still. I have for the last 55 years, (51 years as a professional designer), but I have also done my years of audio repair, etc. Take it from me, 50 years of repair does not a circuit designer make! '-)
Ah, ok. I didn't realize you dis-assembled the wire so that the exact same shield and shield connectors could be used while swapping out the cores.
Ed, you are incorrect.
You are not the first to err in this way.
John
The only time I saw affects is with measuring reflected ripple (VSWR) from the source Z mismatch and from load Z mismatch.
I have several network analyzers.... How would I do a test with them to see directional cable characteristics?
THx-RNMarsh
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The same physics which explains directional effects in some RF cables also prohibits directional effects in ordinary audio cables.simon7000 said:
The effects you describe cannot occur at audio frequencies for two reasons:CG said:
1. audio cables are usually too short
2. audio cables do not have simple resistive frequency-independent characteristic impedance
Perhaps, but quite irrelevant to audio interconnects which cannot be sensitive to details of the conductors unless those conductors were hugely worse in behaviour than any metal. If all the copper atoms faced the same way you would not see any directional behaviour as an audio connection.john curl said:
Tempering of metal usually involves rather extreme temperature to accelerate the proccess. Some proccesses for wires use high electric current through the wire itself to reach tempering temperature, others use induction heating and cryogenics. I am quite surprised to know that there is a relatively short process (weeks) that works for silver wire at room temperature, it takes months to years to temper some steel at room temperature. Sadly information of the TTT curve for silver eutectoid is not readily available to help you accelerate the proccess John.
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