Chris,
I though profanity was not allowed, Computer power supl....! Wow what a nasty term!
Actually my scope throws off enough energy to show up on sensitive measurements!
I just found it real interesting that the IEC connector disconnect and reconnect had that much difference!
Have Fun.
ES
I though profanity was not allowed, Computer power supl....! Wow what a nasty term!
Actually my scope throws off enough energy to show up on sensitive measurements!
I just found it real interesting that the IEC connector disconnect and reconnect had that much difference!
Have Fun.
ES
Mention that to SY, we were discussing what peak current demands do to real power cords!
OK, here is what I was doing today.
Instead of showing what happens on a scope when a very low level signal goes through a component, I decided to show how noise is generated. Shown is a switch switching two different signals both a 1k sine wave, but one 100 times the voltage of the other. The lower voltage creates much more noise because it is not being switched cleanly.
Also shown is a soldered jumper. It is quiet even at the lower voltage.
Yellow is the capacitor from yesterday at the higher voltage. Magenta mostly hidden by the almost the same red is the switch at higher voltage. Dark blue is the switch at lower voltage. Light blue is the jumper. The red is a pot wiper in the mix. It is at high voltage and is slightly noisier than the switch, but better than the cap.
You can see the difference in test voltages but only the top color shows (The light blue hides the dark blue as both are exactly the same.)
Just to be sure the AP is powered from the AC iso transformer!
0 db is around 1 V rms
Instead of showing what happens on a scope when a very low level signal goes through a component, I decided to show how noise is generated. Shown is a switch switching two different signals both a 1k sine wave, but one 100 times the voltage of the other. The lower voltage creates much more noise because it is not being switched cleanly.
Also shown is a soldered jumper. It is quiet even at the lower voltage.
Yellow is the capacitor from yesterday at the higher voltage. Magenta mostly hidden by the almost the same red is the switch at higher voltage. Dark blue is the switch at lower voltage. Light blue is the jumper. The red is a pot wiper in the mix. It is at high voltage and is slightly noisier than the switch, but better than the cap.
You can see the difference in test voltages but only the top color shows (The light blue hides the dark blue as both are exactly the same.)
Just to be sure the AP is powered from the AC iso transformer!
0 db is around 1 V rms
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Hi Ed,
Pretty much!
On the current peaks ... yes. What can go on may really be an eye opener for some people out there.
Hi John,
Now, before we start to go on about equipment that doesn't have enough resolution (hogwash), just consider all the extremely sensitive test equipment out there that use IEC power cords. These are far more sensitive than any audio equipment made by anyone - sorry.
-Chris
Pretty much!
I have a Philips PM3070 scope that shuts down any FM calibration. It's is horrible for RF emissions! Keep in mind that I've owned this from new, so it's lived a known, easy life. I got another of the same model, same problems. That's got to be pretty bad in anyone's books. I just got a Tek 2465B CT. I sure hope it doesn't suffer the same faults!
On the current peaks ... yes. What can go on may really be an eye opener for some people out there.
Hi John,
I'm really sorry John, this isn't true for all equipment. There are some designs where the power supply has been done correctly. The end result of a well designed power supply (and the rest of it) is that they are relatively immune to minor power supply problems. These certainly are immune to a problem where they can sound different depending on what power cord is used. In fact, if what you are alleging is true, nothing short of a permanently attached power supply cable would be acceptable.
Now, before we start to go on about equipment that doesn't have enough resolution (hogwash), just consider all the extremely sensitive test equipment out there that use IEC power cords. These are far more sensitive than any audio equipment made by anyone - sorry.
-Chris
Huh? And the rocketts only perform twice on saturday..
I need more splainin dude..
Cheers, John
Huh? And the rocketts only perform twice on saturday..
I need more splainin dude..
Cheers, John
What I am looking for is what happens when you go from no power to some small level. The common assumption is that ohms law holds. I think that when there is a contact some minimum voltage must occur before conduction starts.
The electrolytic capacitor was used because it has mechanical connections inside a reasonably well sealed case. Of course there are lots of other issues in that case. I was trying to demonstrate the issue with a scope plot. Seems that was not clear enough. So instead I am showing how "Noise" increases as level drops across a switch but not in a soldered connection.
I also expect "Noise" to increase with other factors, but a few more tests need to be done.
Now if you want to talk about voltage and phase shift current in a 1000 uf cap at 20 mv from a 100 ohm source to a 5m input it is there but it ain't much!
Huh? And the rocketts only perform twice on saturday..
I need more splainin dude..
Cheers, John
I still don't get it either.
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You aren't freaking me out in any way.
There are 2 separate issues here, yet, they are connected.
Actually, it's but one issue, observed under two conditions.
It turns out that electricity supply, in many cases has a big impact on sound systems (and on measurement systems).
Isolation transformers do make a difference.
The resistance of power cords do make a difference.
The screen of power cords do make a difference.
The resistance (or oxidation) of power connectors do make a difference.
Now, it seems that there are two parties here, concerning the views about the real impact of electricity supply on sound systems. One party tend to deny such in impact, on the ground that such impact isn't proved scientifically. As long as it isn't proved scientifically, to them, it doesn't exist, not in reality, apart from the imagination of "audiophiles".
When such an impact is shown in a measurement system, as was the case Ed Simon reported here, the "imagined" impact isn't valid anymore.
Most audiophiles don't make measurements on their sound system, especially not on the system as a whole. Yet many audiophiles report audible impact of isolation transformers, different power cords and power outlet sockets.
My point is that the impact of those things on the sound of a system may well be a very real one, not imagined one. Ed Simon's report is an indication for such a possibility, for a real and genuine impact on the mains power supply on the sound of the system.
This may well be so (that there is audio electronics gear on the market that is immune to whatever may happen on the mains power supply).
Only, so far I haven't encountered such gear.
It may be useful if you'd give actual examples.
This is real ... like when there is NO ground , or a high resistance one ... or the latter with a half dozen "bad power factor" loads running on it.
Sometime so much that even a high end, properly designed supply is affected.
Short of the ones that have a true "technical ground", most residential mains services are far from ideal.
OS
Computer Power Supply (CPS) vs. devine power grid.
Suppose you were amplifier God coming to earth and being in a position to dictate a new AC grid from the audio perspective. I would go for AC at 40.000 c/s. The reason being that this is well above the audio frequency, would allow for cute little power transformers with only a couple of windings, would give me a tremendous amount of surge capacity from small capacitors, you name it.
But then you find out that power grid engineers don't take dictates well and so they put mother nature in between You and Your demands. Whole grid can't be done at 40KC/s because of skin effect, EMR losses; you know engineers, there will be a whole list. But, however a difficult bunch these engineers might be, willing to please their masters is one their acknowledged better qualities. So, they propose this clever alternative. Take 60 Hz AC, rectify, condition, switch up to a heavenly 40 KHz, transform, then rectify again. As a further gesture, put in some clever feedback so that you can have a load independant DC voltage! Then, to nail the deal down, they would tell You that this could be done within an input voltage range from 80-240 Volts. In other words, that even the dirtiest, grimiest, oxidated power cords could be used without any degradation to the output.
That would have swayed Me if I had been in that devine position, because even my 40 Khz AC grid would not have allowed for those latter two tricks.
Comes along this guy that says "Computer Power Supply is a profanity".
Suppose you were amplifier God coming to earth and being in a position to dictate a new AC grid from the audio perspective. I would go for AC at 40.000 c/s. The reason being that this is well above the audio frequency, would allow for cute little power transformers with only a couple of windings, would give me a tremendous amount of surge capacity from small capacitors, you name it.
But then you find out that power grid engineers don't take dictates well and so they put mother nature in between You and Your demands. Whole grid can't be done at 40KC/s because of skin effect, EMR losses; you know engineers, there will be a whole list. But, however a difficult bunch these engineers might be, willing to please their masters is one their acknowledged better qualities. So, they propose this clever alternative. Take 60 Hz AC, rectify, condition, switch up to a heavenly 40 KHz, transform, then rectify again. As a further gesture, put in some clever feedback so that you can have a load independant DC voltage! Then, to nail the deal down, they would tell You that this could be done within an input voltage range from 80-240 Volts. In other words, that even the dirtiest, grimiest, oxidated power cords could be used without any degradation to the output.
That would have swayed Me if I had been in that devine position, because even my 40 Khz AC grid would not have allowed for those latter two tricks.
Comes along this guy that says "Computer Power Supply is a profanity".
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That would mean noiseless resistors are possible i.e. only nano-volts of signal available to overcome the contact barrier. The above statement is wrong in my OPINION except you will also find no reference in any physics journal to support that as a general principle.
People have used thermocouples some with tiny outputs for many years, you would expect this "problem" to be frequently mentioned.
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One company I worked for was doing DSC, we were measuring to better than 0.0001 Centigrade with thermocouples, connectors in the way and all, just a bit of noise to contend with. We were resolving better than a nanovolt at dc from -150C to +750C, just noise and control loop jerk to contend with.
Wrinkle
Hi Scott,
I love the fact that you brought up thermocouples. Just their existence and the the fact that they are commonly used in industry within very electrically noisy environments might suggest to a few here that they ought to take another look at the belief system they operate under. Was that a run-on sentence, or what?
I like how some people like to suspend the laws of physics for audio applications.
Hi Stuart,
-Chris
I love the fact that you brought up thermocouples. Just their existence and the the fact that they are commonly used in industry within very electrically noisy environments might suggest to a few here that they ought to take another look at the belief system they operate under. Was that a run-on sentence, or what?
I like how some people like to suspend the laws of physics for audio applications.
Hi Stuart,
We got'em up here in Canada in Sudbury, Ontario - deep underground in a Nickle mine. The largest photon detector around except for the larger one they are building there.
-Chris
Hi,
I have worked quite extensively with both thermocouples and strain gauges in noisy industrial environments. There is indeed much to learn...
BTW, would you venture a guess as to the source impedance of a thermo couple? Trust me, this is important...
Ciao T
I have worked quite extensively with both thermocouples and strain gauges in noisy industrial environments. There is indeed much to learn...
BTW, would you venture a guess as to the source impedance of a thermo couple? Trust me, this is important...
Ciao T
Hi Joshua,
Those who do pursue an understanding of observations do in fact, observe. They are also far more willing to reexamine the accepted norm with regard to contrary evidence that may appear. However, claims must be reproducible for one so that others may recreate the observed phenomenon. Some things that physicists are looking at are somewhat stranger and far more fragile as a signal than anything in audio land can compare to. Okay, you're going to ask me for an example. Look up what research is going on in Sudbury, the lengths they have to go to for keep any noise to a bare minimum for their experiments. These areas are the cleanest rooms on the planet (in the planet?). They are detecting and quantifying single photon counts. Energy far lower than exists on tape or record grooves.
I know people close to me who "know" medical facts that are not accepted by medical science. It is true we don't know much about how our bodies work, but what we do know is generally pretty solid. My father died as a result of quackery, alternative beliefs that contradict the state of medical knowledge as it stands now. These folks do belief they are correct and have studied for many years in this alternate viewpoint. My father still died, and he still suffered more than he had to. The people involved were dead wrong, and even after the death of my father, they were able to blame their failure on the current medical system even though they had no effect. Now, this is the critically important thing to grasp. Neither of these people had any proper education in medicine, nothing at all. Yet they felt that they were in a position to make a judgment on the validity of medical knowledge and practices. Without any proper knowledge, experience or equipment, they felt they were correct in their views. What a crock!
If an audiophile should feel they want to learn about their equipment, I feel they should be encouraged. However, if they are unwilling to be educated properly and invest time learning how to make measurements and even how to plan an experiment, they have to realize that they haven't a leg to stand on. If they will not invest in test equipment and the knowledge to properly use it, they haven't the right to comment. If they wish to be an expert on the subject, then they must invest time, money and effort to learn how things are done properly. From there, they can experiment further and really understand what is happening.
All this fails on the idea of what is or can be a reasonable conclusion. Once you suspend reason, you have nothing left to hold onto. We need more than "it could happen".
-Chris
Only with improperly connected equipment, or in inferior equipment. Sorry, but that is the truth in a nutshell. It really is that simple.
They can, and I use them sometimes when they are the correct tool for the job (or problem).
They can. However, you can't isolate a few feet of power cable from the rest of the building circuits or the power grid as you move away from the end use. Many times the rest of the network will overshadow what's going on with your little IEC cord. That is unless the IEC cord in question has a problem that becomes the dominating issue. Clear and simple.
Not as far as line frequency power is concerned. The screen is actually normally used to keep RF noise from the equipment using the IEC cord from radiating into the area. Keep in mind that as soon as you reach the power outlet, the shielding ceases and you're back to the entire power delivery system. If this worries you, then you must use metallic conduit (not BX cable) and metal boxes and metal outlet covers. This treatment would very probably make a huge positive change in systems that required a shielded power cord. BTW, that is the standard for commercial wiring above 6' I think.
Sure it does. That is something we call a defective cable or socket here. You repair / replace defective things in order to restore normal performance - right?
Look Joshua, you can't drag that hornet's nest out any time it suits you. For one thing, it is patently untrue and a very misleading point of view. This entire idea is but a protective hole some people crawl into if their comfortable beliefs are challenged.
Those who do pursue an understanding of observations do in fact, observe. They are also far more willing to reexamine the accepted norm with regard to contrary evidence that may appear. However, claims must be reproducible for one so that others may recreate the observed phenomenon. Some things that physicists are looking at are somewhat stranger and far more fragile as a signal than anything in audio land can compare to. Okay, you're going to ask me for an example. Look up what research is going on in Sudbury, the lengths they have to go to for keep any noise to a bare minimum for their experiments. These areas are the cleanest rooms on the planet (in the planet?). They are detecting and quantifying single photon counts. Energy far lower than exists on tape or record grooves.
No, "imagined impacts" were never valid to begin with if they can not stand up to scrutiny. As better testing equipment methods and procedures become available, changes are sometimes made to what is accepted as "the way things are or work". People who do follow scientific methods are not afraid to reevaluate their position if reliable data contradicts what is known.
So. What does that tell you? Think about this first.
I know people close to me who "know" medical facts that are not accepted by medical science. It is true we don't know much about how our bodies work, but what we do know is generally pretty solid. My father died as a result of quackery, alternative beliefs that contradict the state of medical knowledge as it stands now. These folks do belief they are correct and have studied for many years in this alternate viewpoint. My father still died, and he still suffered more than he had to. The people involved were dead wrong, and even after the death of my father, they were able to blame their failure on the current medical system even though they had no effect. Now, this is the critically important thing to grasp. Neither of these people had any proper education in medicine, nothing at all. Yet they felt that they were in a position to make a judgment on the validity of medical knowledge and practices. Without any proper knowledge, experience or equipment, they felt they were correct in their views. What a crock!
If an audiophile should feel they want to learn about their equipment, I feel they should be encouraged. However, if they are unwilling to be educated properly and invest time learning how to make measurements and even how to plan an experiment, they have to realize that they haven't a leg to stand on. If they will not invest in test equipment and the knowledge to properly use it, they haven't the right to comment. If they wish to be an expert on the subject, then they must invest time, money and effort to learn how things are done properly. From there, they can experiment further and really understand what is happening.
Depending on how you define a "possibility", you could accept anything I guess. But, where does this leave you? It leaves you in a situation where anything is possible and you have ceased to add to any knowledge of any subject. In fact, back you go into the dark ages as knowledge dissolves into unsupported rhetoric and fantastic stories.
All this fails on the idea of what is or can be a reasonable conclusion. Once you suspend reason, you have nothing left to hold onto. We need more than "it could happen".
-Chris
www.omega.com/temperature/z/pdf/z021-032.pdf
An outline of the operation and interfacing of thermocouples, including methods to make accurate, low noise measurements, from one of the top suppliers of TCs and signal conditioning equipment in the world. The application to audio is not clear.
An outline of the operation and interfacing of thermocouples, including methods to make accurate, low noise measurements, from one of the top suppliers of TCs and signal conditioning equipment in the world. The application to audio is not clear.
Hi,
Some are asking about the application of thermocouples to audio. There is non.
My point was that in a given system susceptibility to external interference varies with a range of parameters. A thermocouple is a dead short, a few milliohm at worth, so the systems susceptibility to external noise is different than to that of a sensor or other source with appreciable resistance/impedance, like for example a resistive straingauge load cell or perhaps a coil based electromagnetic transducer...
If we where (for arguments sake) to add 200 Ohm of resistance in a form that does not add other problems to our thermocouple our susceptibility to noise would be much greater and the same system that at a source resistance of milliohm had good resistance to noise will now suddenly show all sorts of gremlins at low levels, where previously it did not.
This of course is also well known, but often forgotten.
Whenever someone uncritically quotes "precise measurements from XXX in a noisy environment with connectors and all in the way", to justify the "cables cannot make a difference" belief I am always interested to find out if they actually know some of the circumstances that aid such or not.
And I am equally interested if they know the circumstances that may or may not cause problems in extant and practical systems (audio or not) that differ from their comparison system cited...
Ciao T
PS, as remarked elsewhere, I spend time working with systems using thermocouples, PT100 Temperature sensors, resistive straingauge loadcells and even potentiometer based mechanical signaling in the 80's. Very interesting and very instructive, especially when things went wrong.
Some are asking about the application of thermocouples to audio. There is non.
My point was that in a given system susceptibility to external interference varies with a range of parameters. A thermocouple is a dead short, a few milliohm at worth, so the systems susceptibility to external noise is different than to that of a sensor or other source with appreciable resistance/impedance, like for example a resistive straingauge load cell or perhaps a coil based electromagnetic transducer...
If we where (for arguments sake) to add 200 Ohm of resistance in a form that does not add other problems to our thermocouple our susceptibility to noise would be much greater and the same system that at a source resistance of milliohm had good resistance to noise will now suddenly show all sorts of gremlins at low levels, where previously it did not.
This of course is also well known, but often forgotten.
Whenever someone uncritically quotes "precise measurements from XXX in a noisy environment with connectors and all in the way", to justify the "cables cannot make a difference" belief I am always interested to find out if they actually know some of the circumstances that aid such or not.
And I am equally interested if they know the circumstances that may or may not cause problems in extant and practical systems (audio or not) that differ from their comparison system cited...
Ciao T
PS, as remarked elsewhere, I spend time working with systems using thermocouples, PT100 Temperature sensors, resistive straingauge loadcells and even potentiometer based mechanical signaling in the 80's. Very interesting and very instructive, especially when things went wrong.
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