Hi,
In a single metal you won't.
Here's a more indepth explanation:
PELTIER EFFECT.
See also Seebeck effect on the bottom of the page.
Cheers,
In a single metal you won't.
Here's a more indepth explanation:
PELTIER EFFECT.
See also Seebeck effect on the bottom of the page.
Cheers,
Some reading about the Peltier effect, and the 2 other ones (Thermocouple (Seedback effect), and the Thomson (aka Lord Kelvin) effect)
http://www.marlow.com/TechnicalInfo/frequently_asked_questions_faqs.htm
http://www.thermoelectrics.com/introduction.htm
http://www.marlow.com/TechnicalInfo/frequently_asked_questions_faqs.htm
http://www.thermoelectrics.com/introduction.htm
fdegrove said:Hi,
In a single metal you won't.
Here's a more indepth explanation:
PELTIER EFFECT.
See also Seebeck effect on the bottom of the page.
Cheers,
another googler
Ahhh..peltier...
The conversion of current into heat transport is Peltier.. The amount of heat that is transported across a two metal junction is dependent on the current, and the peltier coefficients..so, the amount of signal energy lost through the conversion to heat transport is proportional to current..Resistive loss within a conductor is proportional to current squared..
The efficiency of the peltier process depends on the conductivity of the metals, and the coefficients of the two metals..
Silicon is used for peltier modules for control of the material coefficients, and to reduce the efficiency lost when the heat tries to conduct in a direction opposite of that desired. The parameter being optimized is called the figure of merit..which relates the seebeck coefficient, the electrical conductivity, and the thermal conductivity of the materials...silicon is tuned to increase that figure.
Seebeck conversion is the opposite process..BUT, the efficiency is proportional to the difference in temperature of the two sides of the metal interface. For small signal wires carrying little current, this temp difference is very small, rendering the Seebeck energy return possibility moot..
As to being "dissed" by John Curl in another forum regarding peltier......none of his criticisms had any validity, so will not be addressed by me..
Cheers, John
The conversion of current into heat transport is Peltier.. The amount of heat that is transported across a two metal junction is dependent on the current, and the peltier coefficients..so, the amount of signal energy lost through the conversion to heat transport is proportional to current..Resistive loss within a conductor is proportional to current squared..
The efficiency of the peltier process depends on the conductivity of the metals, and the coefficients of the two metals..
Silicon is used for peltier modules for control of the material coefficients, and to reduce the efficiency lost when the heat tries to conduct in a direction opposite of that desired. The parameter being optimized is called the figure of merit..which relates the seebeck coefficient, the electrical conductivity, and the thermal conductivity of the materials...silicon is tuned to increase that figure.
Seebeck conversion is the opposite process..BUT, the efficiency is proportional to the difference in temperature of the two sides of the metal interface. For small signal wires carrying little current, this temp difference is very small, rendering the Seebeck energy return possibility moot..
As to being "dissed" by John Curl in another forum regarding peltier......none of his criticisms had any validity, so will not be addressed by me..
Cheers, John
peranders said:
The Mac The Scope software references to 1 volt. So John's analyzer is applying some gain to the residual output making direct comparison of the Mac The Scope plots difficult at best.
To get an idea as to how the Mac The Scope and AP plots compare, I included this in my original post:
Steve, the notch filter in the 1700B notches out to somewhere between -94 and -100dB This can be shown by the RESIDUAL of the THD at all levels is a little less than .002% or -94dB. Of course at very low levels, NOISE makes the residual appear to increase on the meter. This residual includes the unnotched fundamental ( the highest peak on the left side at 1KHz), the averaged distortion residual, and NOISE. At low levels, noise is all important, and this is why I must use signal averaging or very narrow bandwidth filtering to remove enough noise to look at the distortion residual. If you start with my graphs with the IKHz (notch) then you can see that the noise boundary is about -125dB. The distortion occurs in this case about -115 to -120dB, or even as much as -110dB if the notch is not complete.
Using this as a guide to make a comparison of the levels John's measuring at versus where the System Two Cascade's measuring at, this is approximately how John's Radio Shack measurement would compare:
An externally hosted image should be here but it was not working when we last tested it.
Or to put it another way, if cables were producing the high order harmonic distortion components at the levels that John says he's measuring, then if measured on the System Two Cascade, we should see their peaks reaching up into the region of the red band in this image:
An externally hosted image should be here but it was not working when we last tested it.
se
Just to add my 2 cents:
Here a loop trough measurement of 5 m el cheapo Belden CATV cable. It is an average of 256 synchronous measurements. Averaging was done in the complex domain of the FFT. Signal was – 10dB below full scale. The audio card was an M-Audio Audiphile 2596, @ 24 bit / 48 kHz.
The very low noise floor is due to the averaging. The real measurement floor is probably something of -130 dB, I guess. The harmonics seen are for sure the distortion of the card. They rise a lot at 0 dB signal level, just before clipping. At -40 dB signal the distortion vanishes completely from the plot
BTW no cleaning of the cable connectors and card jacks was done (cinch).
Here a loop trough measurement of 5 m el cheapo Belden CATV cable. It is an average of 256 synchronous measurements. Averaging was done in the complex domain of the FFT. Signal was – 10dB below full scale. The audio card was an M-Audio Audiphile 2596, @ 24 bit / 48 kHz.
The very low noise floor is due to the averaging. The real measurement floor is probably something of -130 dB, I guess. The harmonics seen are for sure the distortion of the card. They rise a lot at 0 dB signal level, just before clipping. At -40 dB signal the distortion vanishes completely from the plot
BTW no cleaning of the cable connectors and card jacks was done (cinch).
Attachments
Pjotr said:Who can say the distortion seen in Jonh's measurements, is due to diode effects and not caused by dielectric hysteresis
Because in light of the AP measurements, it appears that the distortion John's been measuring is being produced by his distortion analyzer, and not the cables. So the issue of diode effects versus dielectric hysteresis is rather moot, yes?
The AP measurements are measuring well below here John's measuring, but even with a bog standard A/V cable, there's no evidence of the kind of distortion that appears in John's measurements.
se
Steve Eddy said:
Agree,
I just mentioned dielectric hysteresis because not many seem to be aware of. But anyhow even that did not show up. The distortion profile of John’s pics has much resemblance with cross-over distortion IMHO.
Even if there is such thing as a diode effect in a cable, why should those many diodes be aligned in one direction so it can cause a rectifying effect? And when it can cause a rectifying effect, one can measure a DC component at the cable. Measuring DC is possible to deeper levels than measuring distortion with an AP if proper measurements are taken to get rid of thermo electric voltages.
Cheers
Re: Re: CCD
Hi guys,
I followed this thread with interest; finally somebody at least tried to measure if there is anything to the stories.
I looked at the CCD page from VDH. I find the contamination story convincing; even silverware quickly changes color after some time in open air due to chemical contamination. But one thing keeps bugging me. If we accept that this contamination changes (decreases) cable conductivity, why can't we just measure that with an ohmmeter? Or can we?
Jan Didden
"Can I have this speaker cable, sir?"
"Yes, of course. Will that be smoking or non smoking, please?"
Steve Eddy said:
Hi guys,
I followed this thread with interest; finally somebody at least tried to measure if there is anything to the stories.
I looked at the CCD page from VDH. I find the contamination story convincing; even silverware quickly changes color after some time in open air due to chemical contamination. But one thing keeps bugging me. If we accept that this contamination changes (decreases) cable conductivity, why can't we just measure that with an ohmmeter? Or can we?
Jan Didden
"Can I have this speaker cable, sir?"
"Yes, of course. Will that be smoking or non smoking, please?"
For the record, Steve Eddy likes to second guess me, and the nature of my measurements. SE, to the best of of my understanding, has not done any testing himself, and has no access to the schematics of the circuitry that is in my test equipment.
His assessment of my measurement is pure conjecture, based on ONE NULL RESULT, that someome else made with another measurement system with different wires.
I would concur that if there is a problem with my measurements, there should be an engineering level reason for it. SE likes to say 'crossover distortion', well why does the analyzer system give a different result with each wire type? Inherent crossover distortion in either the oscillator buffer or the input stage of the analyzer should be consistent with a similar load in each case.
Could it be a special oscillation that is specifically dependent on the properties of each cable? Yes, if the cables were directly connected to the active devices, BUT they are resistively buffered on both sides, with more resistance than would typically be used with an audio stage. The reasons should be noted, first the oscillator operates at about a 3V level and this must be resistively attenuated to 30 mV, at the same time a 600 ohm drive impedance is created. On the input, there are relays across each input to protect from overvoltage. These relays need to be current protected to keep them from being destroyed the first time they are used. Therefore, each input, both hot and ground have a 500 ohm resistor in order to limit peak currents. This has not been changed in my equipment. Therefore it is very difficult to see how a specific cable can effect my equipment to make different measurement results. I am open to serious suggestions.
His assessment of my measurement is pure conjecture, based on ONE NULL RESULT, that someome else made with another measurement system with different wires.
I would concur that if there is a problem with my measurements, there should be an engineering level reason for it. SE likes to say 'crossover distortion', well why does the analyzer system give a different result with each wire type? Inherent crossover distortion in either the oscillator buffer or the input stage of the analyzer should be consistent with a similar load in each case.
Could it be a special oscillation that is specifically dependent on the properties of each cable? Yes, if the cables were directly connected to the active devices, BUT they are resistively buffered on both sides, with more resistance than would typically be used with an audio stage. The reasons should be noted, first the oscillator operates at about a 3V level and this must be resistively attenuated to 30 mV, at the same time a 600 ohm drive impedance is created. On the input, there are relays across each input to protect from overvoltage. These relays need to be current protected to keep them from being destroyed the first time they are used. Therefore, each input, both hot and ground have a 500 ohm resistor in order to limit peak currents. This has not been changed in my equipment. Therefore it is very difficult to see how a specific cable can effect my equipment to make different measurement results. I am open to serious suggestions.
Pjotr said:
Yes, I'm aware of hysteresis in dielectrics, but I don't recall ever seeing anything about their exhibiting hysteresis anywhere near the audio band. Doesn't dielectric hysteresis occur more around the X-ray region of the spectrum?
If you've some sources on the matter, I'd be interested.
Yes.
Yes, I'd mentioned the same in the past. If there's any nonlinear I/V relationships, one needn't use AC signals to measure it.
As I'd related before, I recall reading somewhere that some researcher thought he had observed rectifying effects in copper wire, but on further investigation it turned out to be the contacts of his aparatus.
In any case, I simply don't see how copper wire could have the gross nonlinearities shown in John's measurements. I find it rather hard to swallow that a length of copper wire can be more nonlinear than than a complex active circuit such as an opamp.
And I find it even more difficult to believe that such gross distortions in copper wire could have wholly escaped the entire notice of everyone, including materials science researchers.
se
john curl said:
So? What has that to do with the measurements which Bruno made?
Of course it was made on another measurement system, John. That was the whole point!
If the distortion you were measuring were being produced by your measurement system, what the hell good would it have done to repeat the tests using the same system? It likely would have turned up the same result and we'd still be wondering whether the distortion was being produced by the measurement system or the cables.
And what's with this "ONE NULL RESULT" nonsense? We're not talking about blind listening tests here, John. Cable distortions don't suffer from test anxiety.
And so what if the wires weren't the exact same wires you measured? You mean these micro diodes only inhabit the wires that you an van den Hul measure?
In any case, if you want to look at it in such terms, then these new measurements have shown that a bog standard A/V cable with plain Jane ETP copper wire, PVC insulation, molded RCA plugs, etc., clearly demonstrated that they were far better than your best van den Hul reference cable.
And by the way, I have offered you the opportunity to measure the same cables that Bruno will be measuring.
I have an old 12 foot set of Radio Shack Gold interconnects as well as a brand new, never used set that I bought the other day specifically for this purpose. I also have an 8 foot set of cheap A/V cables that came with my DishNetwork boxes.
I've taken each of these and split their left/right channels in two so that you and Bruno can each have as exactly the same cables as possible short of shipping the same cables back and forth.
Bruno has already kindly accepted and I'll be mailing out his set this week. I made you the same offer back on the 28th on another forum but have not heard from you at all on the matter. Perhaps you haven't been there since the 28th.
The offer still stands. Will you accept so that the issue of measuring different wires can be properly addressed?
Bottom line, it's not my problem. It's your test equipment. You figure it out. You're one of the "big boys" remember?
All I know is that on a modern, reference standard measurement system known to have significantly greater resolution that what you're using, there are no signs of the high order harmonic distortion products that you've been measuring even when measured at levels far below what your system is capable of and even when the cables measured included a bog standard giveaway A/V cable.
So you'll excuse me if I take this as pretty good evidence that the distortion that you're measuring is being produced, for whatever reason, by your distortion analyzer.
Again, my offer still stands to send you a duplicate set of cables. Take it or leave it.
se
Pjotr said:
I've seen no indication of any dc effects with any combination of currents from picoamperes to 30 kiloamps...with nano-ohm measurements, nor with nanovolt dc measurements...but I've only checked from 4.5 Kelvin to room temp..so I'll be the first to admit a lack of resources..
john curl said:
He isn't second guessing you..he has presented tests which are more accurate than yours, showing none of the harmonics you report.
john curl said:
Four wires, exact same test criteria...how many null results are necessary??
john curl said:
We've been saying that all along..but you have to date resisted any discussion of that possibility..
john curl said:
Why not test your 1700 with an AP??
john curl said:
We've been trying for a while to no avail...Hopefully, you are really earnest in this desire?
Cheers, John
This is just a speculation but since John did his measurements
at home and this is obviously a far-from-ideal lab environment,
which is obvious from his own explanation of the TV interference,
could it be that also the other frequencies are some kind of
outside interference picked up by the cables? Come to think of
it, could it even be that the cables actually pick up stray
magnetic/electric fields from the signal generator?
John, would it be possible for you to move your test equipment
and repeat the experiments somewhere else, where there is
less outside interference from neighbours, less crap on the
power lines etc.? That would be a first reasonable way of
trying to repeat the experiments.
at home and this is obviously a far-from-ideal lab environment,
which is obvious from his own explanation of the TV interference,
could it be that also the other frequencies are some kind of
outside interference picked up by the cables? Come to think of
it, could it even be that the cables actually pick up stray
magnetic/electric fields from the signal generator?
John, would it be possible for you to move your test equipment
and repeat the experiments somewhere else, where there is
less outside interference from neighbours, less crap on the
power lines etc.? That would be a first reasonable way of
trying to repeat the experiments.
Re: Re: Re: CCD
Sure. On it's SURFACE.
But van den Hul's claiming that this contamination (or rather the contamination that he's talking about) is INTERNAL. In other words, at all of the internal interfaces of the crystals that make up the wire.
I've done quite a lot of searching but I have yet to find any evidence substantiating this claim.
He also says that the process is on-going and becomes worse with time. Yet there are copper artefacts which are THOUSANDS of years old, and except for surface patina, are in excellent shape, even though these artefacts were produced using very primitive methods compared to how copper is produced today.
Don't see why not.
Though if you want to get a bit more exotic, you could measure residual resistivity (resistivity measured while the wire is supercooled to 4.2 degrees Kelvin), let it age and then measure it again.
se
janneman said:
Sure. On it's SURFACE.
But van den Hul's claiming that this contamination (or rather the contamination that he's talking about) is INTERNAL. In other words, at all of the internal interfaces of the crystals that make up the wire.
I've done quite a lot of searching but I have yet to find any evidence substantiating this claim.
He also says that the process is on-going and becomes worse with time. Yet there are copper artefacts which are THOUSANDS of years old, and except for surface patina, are in excellent shape, even though these artefacts were produced using very primitive methods compared to how copper is produced today.
Don't see why not.
Though if you want to get a bit more exotic, you could measure residual resistivity (resistivity measured while the wire is supercooled to 4.2 degrees Kelvin), let it age and then measure it again.
se
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