Hi,
Not you.
Your comment was immediatly seized upon by some to say "see, if this is possible any cable differences must be imagination" and that is what I wanted to address. One needs to know the problem and the solution to understand why some things work.
I have used unscreened twisted pairs for MC cartridges for a good time (learned that from Kondo) and I get no hum from that, but I would not try this with MM pickups (well, I did, once), there are reasons why it works in one case and not in the other, if we do not understand them one may argue that shielding cables is not needed as we do not need it at such low levels as a low output MC Pickup...
All that said, in my experiences with thermocouples they do represent possible problems with careless selection of metal/metal junctions in the connections.
What I experienced where so-called "lance's" which had a meter long asbestos tube with a thermocouple at the front, screwed into the actual steel "lance". The front was stuck into liquid steel to measure the temperature of the steel in the minimal time window between heating up the thermocouple and it actually melting due to the very temperature.
From that thermocouple all the way to actual measurement system we had numerous connections and care needed to be taken to avoid throwing the system out.
This happened so frequently (due to the need to rebuild the lance's every other week and patching cabling burned through by liquid steel and so on) that we devised a special calibration jig to make sure the system from the socket for the couple to the metering in the control centre worked correctly which was used before each and every measurement of temperature.
Routinely the workers had to change the "lance" out as a result because the re-building and a few cycles of plugging/unplugging had cause enough problems that it could no longer be considered reliable. Still, less cost and faster than getting a result that was obvious garbage and much cheaper than getting one that was only a little out...
Of course, all this does not say much, much of this was likely down to bad use, application in part introduced by penny pinching and poor availability of critical items.
What I do remember interestingly, all the relays in the signal section of the metering system where mercury wetted and we later ended up using such too in our own calibration jig (it needed to simulate the rise of the thermocouple voltage, the short plateau and then the instant drop as it melted), as normal dry contact signal relays caused too much trouble...
Ciao T
Not you.
Your comment was immediatly seized upon by some to say "see, if this is possible any cable differences must be imagination" and that is what I wanted to address. One needs to know the problem and the solution to understand why some things work.
I have used unscreened twisted pairs for MC cartridges for a good time (learned that from Kondo) and I get no hum from that, but I would not try this with MM pickups (well, I did, once), there are reasons why it works in one case and not in the other, if we do not understand them one may argue that shielding cables is not needed as we do not need it at such low levels as a low output MC Pickup...
All that said, in my experiences with thermocouples they do represent possible problems with careless selection of metal/metal junctions in the connections.
What I experienced where so-called "lance's" which had a meter long asbestos tube with a thermocouple at the front, screwed into the actual steel "lance". The front was stuck into liquid steel to measure the temperature of the steel in the minimal time window between heating up the thermocouple and it actually melting due to the very temperature.
From that thermocouple all the way to actual measurement system we had numerous connections and care needed to be taken to avoid throwing the system out.
This happened so frequently (due to the need to rebuild the lance's every other week and patching cabling burned through by liquid steel and so on) that we devised a special calibration jig to make sure the system from the socket for the couple to the metering in the control centre worked correctly which was used before each and every measurement of temperature.
Routinely the workers had to change the "lance" out as a result because the re-building and a few cycles of plugging/unplugging had cause enough problems that it could no longer be considered reliable. Still, less cost and faster than getting a result that was obvious garbage and much cheaper than getting one that was only a little out...
Of course, all this does not say much, much of this was likely down to bad use, application in part introduced by penny pinching and poor availability of critical items.
What I do remember interestingly, all the relays in the signal section of the metering system where mercury wetted and we later ended up using such too in our own calibration jig (it needed to simulate the rise of the thermocouple voltage, the short plateau and then the instant drop as it melted), as normal dry contact signal relays caused too much trouble...
Ciao T
Hi,
Perhaps, this was over two decades ago and our job was not to recommend a different system (and I am not a specialist in thermocouples), but to make sure that darn junk we had worked with sufficient reliability and accuracy to be usable...
Ciao T
Perhaps, this was over two decades ago and our job was not to recommend a different system (and I am not a specialist in thermocouples), but to make sure that darn junk we had worked with sufficient reliability and accuracy to be usable...
Ciao T
Scott,
We have already discussed Paschen's law. I mentioned my plasma days and some additional work I have seen on how arcs actually propagate.
I am getting interesting data. Passing a 1nv sine wave the switch under test is showing noise at a level 20 to 30 db below that. You are welcome to your own opinion about it. Showing your data at tens of nanovolts agrees with what I see at that level.
There are other experiments I am running at these low levels. As mentioned before the AP system 2 takes a while to average 4k of 32K fft's.
My voltage divider is a 600 ohm jensen isolation transformer stepped down by a 10k/10 ohm divider which then feeds a 100k/100 ohm divider. Right now I am running 100 microvolts out of the AP just to see what changes.
Yes. And, are you enjoying it, do you think it is worth it to be green to use twice as much?
jan didden
What green! It is not often available around here, it was a long trip with a mountain in the middle and the extra HP was nice. The added benefit is all the ethanol leaves a cleaner fuel system. For those who might care I am past 236,000 miles and on regular gas on the trip I was getting 30 mpg in my station wagon.
Do you think you would notice a step discontinuity of .0000001 C? That is the level that seems to be showing up. That would be lost in the noise.
Excellent we agree! So if I get the actual data from those poor datasheet graphics and blow it up and expand the time scale....
Excellent we agree! So if I get the actual data from those poor datasheet graphics and blow it up and expand the time scale....
Great now that we agree can you help me with why on one of my AD797s is 5x noisier than the rest?
I soldered the chips in just to be sure that if contact issues existed they wouldn't be masked by my input amplifier. I used four in parallel and had to pull the output resistor to take the noisy one out of the circuit. If I get around to it I have another PC card and will populate it with selected IC's next time!
Hi Chris,
The "photon detectors" are all photo multiplier tubes so a signal can be amplified enough for reliable detection. They do record single photon events in that lab down below.
-Chris
I sincerely doubt that. To make matters worse, the brain wouldn't recognize a single photon as such even if the signal was not lost in the random noise of our nerves firing. The event would be far too short to register as well. I think what you read might have been a thought experiment.
The "photon detectors" are all photo multiplier tubes so a signal can be amplified enough for reliable detection. They do record single photon events in that lab down below.
-Chris
Hi Joshua,
It is your right to believe what you will. It is also your right to proclaim this and appear lacking in your own experience and education. This defines you as a posting member (your actions).
Read this slowly now so you understand clearly.
Competent designers and technicians not only use testing equipment and knowledge to discover where problems may exist, but they also include observations made with their own two ears, eyes and sense of smell for additional (valuable) information.
You state with certainty that the use of any type of test equipment renders a person incapable of hearing clear changes in sound caused by various equipment and components. You continue to attempt to ram a skewed objectivism vs. subjectivism program into any discussion that may involve any judgment of sound quality. This line of thought is usually outside the parameters of a discussion and serves to cloud the issues at hand.
-Chris
The facts do not differ. Remember that you are not dealing with facts from your point of view. This is extremely important to recognize.
Specific event that most of us have experienced. No relation to what was under discussion.
Your power supplies are very probably poorly designed.
I've had to prove and solve issues like these for over 30 years. Since you don't wish to have to prove anything, you don't. It's another way of ducking an uncomfortable situation. Anyway, this statement has no value.
Don't most of us? I choose equipment on sound quality, and that happens to also go hand in hand with better measured performance. Sometimes there are only tiny differences in a standard THD test, but using more sensitive tests always show some difference. I've been lucky enough to be able to hear almost everything out there both before and after servicing. At the same time, everything I have heard has been measured as part of the same job. This means I've piled up a ton of experience, wouldn't you say?
This isn't the focus here. Not only that, but statements like these are completely pointless. Remember, my viewpoint is that I can both hear and measure differences when they actually exist. All you have said thus far is that you can hear differences, but you don't even attempt to see if you can measure a change in some way. In this way, you are actually making a conscious decision to remain uneducated. It is that simple.
Ahhh, no. You have things turned around there. I am saying that I can measure what I hear. You are saying that what you hear is true no matter if any measurements might possibly contradict what you are hearing. This, even though you are not making any attempt to find out if you can possibly measure something. You are actively refusing to use tools that would assist your own auditory training and decision making. From this platform, you eagerly attack what is said by people who have more information than you do.
It is your right to believe what you will. It is also your right to proclaim this and appear lacking in your own experience and education. This defines you as a posting member (your actions).
Head in sand syndrome.
Here you go again. By assuming the least expensive power cord has no defects or shortcomings which would probably cause a clearly audible indication, you claim that no one will have a problem using it. You set up a silly situation where you think no one using test equipment and listening will detect a problem. Yet you, and others who subscribe to your belief system will be the only ones who can pick the best equipment and parts simply by excluding the use of tools that can clearly show what things have problems.
Read this slowly now so you understand clearly.
Competent designers and technicians not only use testing equipment and knowledge to discover where problems may exist, but they also include observations made with their own two ears, eyes and sense of smell for additional (valuable) information.
You state with certainty that the use of any type of test equipment renders a person incapable of hearing clear changes in sound caused by various equipment and components. You continue to attempt to ram a skewed objectivism vs. subjectivism program into any discussion that may involve any judgment of sound quality. This line of thought is usually outside the parameters of a discussion and serves to cloud the issues at hand.
-Chris
Your extremely long posts are tiresome to read, and on top you are dissecting pretty clear statements into something i am pretty sure the writer did never intend to say.
IF you do not hear a difference between a set of different [put in an equpment or component of your choice], then there is not much reason not to buy the cheapest.
Of course you may chose more expensive [put in the component or equipment of your choice] if you need better looks, reliability or so.
But i hope sincerely that you do not spend more money than needed based on your sonic evaluation. At the end, you need the evaluated [component, equipment, put in your choice] for your enjoyment of reproduced music, voices etc. And not for measurements. Or am I wrong here?
Then maybe you really should listen what your wife says.
IF you do not hear a difference between a set of different [put in an equpment or component of your choice], then there is not much reason not to buy the cheapest.
Of course you may chose more expensive [put in the component or equipment of your choice] if you need better looks, reliability or so.
But i hope sincerely that you do not spend more money than needed based on your sonic evaluation. At the end, you need the evaluated [component, equipment, put in your choice] for your enjoyment of reproduced music, voices etc. And not for measurements. Or am I wrong here?
Then maybe you really should listen what your wife says.
Hi Thorsten,
The actual signal is a high impedance as it can deliver only a very low current. However, connecting a power source across the terminals will cause high current to flow with only a few volts of emf applied. The resistance of each wire is somewhat higher from terminal to junction than you would think. Higher than copper wire is, and the wire is a light gauge on top of that.
Now when doing on on-site calibration, thermocouples are often long wire runs where noise is picked up easily. The series resistance in these cases is substantial compared to even one ohm. A high resistance connecting the two leads that might form as a result of insulation breakdown of an insulating material can really upset the readings to the point where they are well out of tolerance. This is how sensitive the signal is.
The two most common ways to reduce interference from noise pickup is filtering the signal (low pass) and giving the cable a twist (as in twisted pair). Both conductors are insulated from each other. Spools of each wire type are available for this purpose.
So Thorsten, how do you wish to define the impedance? From the desired signal point of view, or the "how much current can we run though" point of view.
You will find copper often used when you are measuring voltage in the nV or current in the uA that requires any sort of accurate result. Meter terminal shorts for calibration use are also normally made from copper (that is cleaned with alcohol just before use - and the jacks too!). I think Keithley would be a good source of information for this. Agilent and Fluke would also have some good information.
-Chris
Now there is a great question. The Seebeck voltage generated by dissimilar metals contacting each other is extremely sensitive to the resistance loading across the terminals. The actual resistance can not be measured accurately using an ohmmeter without resorting to a procedure. You should know this procedure, do you? It's easy to look up, so I'll just add that measuring the resistance of a thermocouple also involves taking a voltage reading at the time the junctions are at a steady, unchanging temperature.
The actual signal is a high impedance as it can deliver only a very low current. However, connecting a power source across the terminals will cause high current to flow with only a few volts of emf applied. The resistance of each wire is somewhat higher from terminal to junction than you would think. Higher than copper wire is, and the wire is a light gauge on top of that.
Now when doing on on-site calibration, thermocouples are often long wire runs where noise is picked up easily. The series resistance in these cases is substantial compared to even one ohm. A high resistance connecting the two leads that might form as a result of insulation breakdown of an insulating material can really upset the readings to the point where they are well out of tolerance. This is how sensitive the signal is.
The two most common ways to reduce interference from noise pickup is filtering the signal (low pass) and giving the cable a twist (as in twisted pair). Both conductors are insulated from each other. Spools of each wire type are available for this purpose.
So Thorsten, how do you wish to define the impedance? From the desired signal point of view, or the "how much current can we run though" point of view.
This is precisely one of the problems in metrology and process control. You can easily end up with 200 ohms of resistance, along with other temperature related issues. It's enough to keep the instrumentation lads up all night!
Any time you have dissimilar metals in contact with each other (solder counts), the Seebeck effect will appear, generating a signal voltage that depends on the metals that are touching (should I say "in contact"?) and temperatures involved. This is unavoidable unless you can keep everything at absolute zero. That's not very much fun though ...
You will find copper often used when you are measuring voltage in the nV or current in the uA that requires any sort of accurate result. Meter terminal shorts for calibration use are also normally made from copper (that is cleaned with alcohol just before use - and the jacks too!). I think Keithley would be a good source of information for this. Agilent and Fluke would also have some good information.
-Chris
Hi sottomano,
Huh?
I've learned that I have expensive tastes for one. Both my wife and I evaluate equipment by listening before a choice is made for two. Her tastes are about the same as mine.
I don't know what you are trying to say here, except that you don't like long posts. It does seem as though you don't read them while paying attention though. With some members, I have learned that an answer must be defined carefully or they will run with them. That is why I post a quote from the post in question before leaving a comment.
So, to be clear here. What do you think the basic standpoint is that I'm taking? Which member am I reducing clear statements to unintended meanings? Now, since these are "clear statements", what do you think they are saying?
-Chris
Huh?
I've learned that I have expensive tastes for one. Both my wife and I evaluate equipment by listening before a choice is made for two. Her tastes are about the same as mine.
I don't know what you are trying to say here, except that you don't like long posts. It does seem as though you don't read them while paying attention though. With some members, I have learned that an answer must be defined carefully or they will run with them. That is why I post a quote from the post in question before leaving a comment.
So, to be clear here. What do you think the basic standpoint is that I'm taking? Which member am I reducing clear statements to unintended meanings? Now, since these are "clear statements", what do you think they are saying?
-Chris
Oh really?
I recall one of these 'rational designers' (ahem) telling me repeatedly that cold fusion does not exist.
E-Cat Competitors Revealed During Viareggio Conference
"Andrea Rossi's E-Cat (Energy Catalyzer) technology has became well known this year, due to it being validated repeatedly by qualified scientists, multiple third parties,...."
paradox means the answer to the poser exists outside of the area searched/known or the question asked is inherently the wrong one-or both.
If observation, which is the first step in 'science', (apparently scientists do that 'science' stuff) presents paradox, then the truth of the matter is therefore outside of knowns or expected aspects.
It really is that simple.
"There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy." -Shakespeare
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Transient current draw ...when the power supply system is conducting....turning into transient phase shift on the part of the signal which is the only part the ear even bothers to work with. The transients. Complex harmonic transient structure, the only part the ear cares about or even hears at all. It can only decode so much and that is the part that ended up being 100% of the observed signal ---for the ear.
The conducting power supply becomes -and is- the power cord as well...Thus we hear a change in power cords.
We've covered this before.
Engineering minds need to weigh the measurements in the same way the ear hears things, then the measurements will correlate to what is heard. Exactly so.
Of course, I found a way to eliminate complex LCR from the 'transmission' equation.
LCR is a PITA, so I just ..well..got rid of it. ("Shoo! Off with you! Don't come back!" )Simple enough.
Ended up with gigahertz response and basically...no real measurable capacitive reactance. (as done in the research lab of a $XXB electronics development company).
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The mechanical ground of a standard bearing system is, er, far more correct.
Long story.
The obvious one is that the stylus and cantilever motion is all about a darned near textbook perfected un-interrupted motion across a huge number of octaves of vibration or motion... so the slightest micro-noise with regard to being an 'untoward motion' - is completely incorrect. Thus such arms have serious faults in the most basic sense and it is easily heard.
Dear Ed,
This is very interesting. I have been doing some inductive reasoning around some of these phenomenae and would like to compare notes, to see how well your results agree with my guesses, do you mind a private message on this?
Ciao T
This is very interesting. I have been doing some inductive reasoning around some of these phenomenae and would like to compare notes, to see how well your results agree with my guesses, do you mind a private message on this?
Ciao T
The above quoted part. He clearly said that there is no point paying more WITHOUT audible benefit. Period.
What has that to do with your answer about shortcomings or defects which can cause „a clearly audible indication“?? Then it would be an audible shortcoming, and goes not under the definition of „no audible benefit“.
Some Guys here seem really to be lawyers picking and fighting single words here and there while they do not hear what someone is saying.
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