vacu, I was reading that yesterday
http://assets.cambridge.org/97805214/25438/frontmatter/9780521425438_frontmatter.pdf
http://www.hermetics.org/pdf/corpushermetica.pdf
George
http://assets.cambridge.org/97805214/25438/frontmatter/9780521425438_frontmatter.pdf
http://www.hermetics.org/pdf/corpushermetica.pdf
George
Attachments
Getting back to power cables, the purpose of twisting is help cancel out stray EM coupling, primarily magnetic. Star Quad is more effective than 2-conductor cable at cancellation, particularly when the coupling is with a very close-by field.
Somebody mentioned earlier, I think, that digital equipment might be more commonly affected by power cables than analog equipment. If so, that would suggest HF EMI/EMC interaction between power cables, and the presence of line-conducted noise.
HF EMI/EMC control can be difficult for designers not following proper design, test, and remediation practices. Sometimes an outside testing lab, and/or a consultant may be needed. Not every equipment designer does the best job with some of those things, as some of it might fall outside the expertise of designing the primary function of what might be fairly specialized equipment.
In the medical device field, EMI/EMC testing and remediation are mandatory. One can't have a defibrillator that is only safe with special power cords, unless perhaps, special power connectors are used to make sure the wrong cable can't be accidentally used. Even then, it's not clear that such a design could pass regulatory approval.
Somebody mentioned earlier, I think, that digital equipment might be more commonly affected by power cables than analog equipment. If so, that would suggest HF EMI/EMC interaction between power cables, and the presence of line-conducted noise.
HF EMI/EMC control can be difficult for designers not following proper design, test, and remediation practices. Sometimes an outside testing lab, and/or a consultant may be needed. Not every equipment designer does the best job with some of those things, as some of it might fall outside the expertise of designing the primary function of what might be fairly specialized equipment.
In the medical device field, EMI/EMC testing and remediation are mandatory. One can't have a defibrillator that is only safe with special power cords, unless perhaps, special power connectors are used to make sure the wrong cable can't be accidentally used. Even then, it's not clear that such a design could pass regulatory approval.
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You clearly missed this pearl of marketing **** https://www.audiostream.com/content/shunyata-research-helps-save-lives
BTW reading of the links here should be mandatory before discussing power cables. Bill Whitlock has covered this well.
BTW reading of the links here should be mandatory before discussing power cables. Bill Whitlock has covered this well.
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George,
Even the hermetics support my position:
"The Earth is brutish, the Heaven is reasonable or rational"
Thank you for once again finding the unlikeliest, yet most appropriate, of all links.
Even the hermetics support my position:
"The Earth is brutish, the Heaven is reasonable or rational"
Thank you for once again finding the unlikeliest, yet most appropriate, of all links.
Well, I just mentioned one cause for trouble with high EM fields from power and speaker cables. I have measured the radiated fields with a portable hand-help instrument. Their construction will vary as does the intensity of the radiated field.
It is not hard to do a low z to high z cable coupling test.
THx-RNMarsh
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Be worried over the legitimacy of anything and all of ‘Hermetics” i.e. neoplatonic escatology. 🙂
Now, in post #93654 you’ve mentioned a loudspeaker you’ve designed.
Is it based on the US …858 ?
George
George,
It is a derivative with improvements. It is a 5 kg speaker that outplayed well designed, high end, pretty expensive speakers, even in a large auditorium, so there should be a market for it. However, I am at a loss as to how to put this design on the market. Money has never been a strong motivator for me. Therefore, I need someone who's primary motivation is in that field, or who at least enjoys building a business. From the 20th of this month onwards I will start with a sabbatical and this is one of the projects on the list.
regards, Vac
It is a derivative with improvements. It is a 5 kg speaker that outplayed well designed, high end, pretty expensive speakers, even in a large auditorium, so there should be a market for it. However, I am at a loss as to how to put this design on the market. Money has never been a strong motivator for me. Therefore, I need someone who's primary motivation is in that field, or who at least enjoys building a business. From the 20th of this month onwards I will start with a sabbatical and this is one of the projects on the list.
regards, Vac
JC
It actually looks like progress is being made! It used to be folks would offer the wisdom that the resistance of the power wiring all the way from the power plant to your personal wall outlet would swamp that of the cord.
Now folks are at least looking at the power cord as a filter.
There are three main issues;
The voltage losses from the cable and connections.
The ability to suppress noise coming in.
Prevent noise going out.
The first issue is easily handled by decent construction. I have seen power cords that are nice and thick, but it is all plastic mot copper. Actually not even good copper as a magnet sticks to it!
The second issue can be a big deal for preamps A/Ds etc. once noise gets into the enclosure it is no longer a simple matter to prevent it from making it into some place where it hurts.
The third is more of an issue for power line noise sources such as audio power amplifiers.
As to your old Stax box, it probably was designed when there were fewer noise sources and the issue had not yet been recognized.
There really are easily done measurements that show the effects of line noise, little magic involved.
George,
Thanks for the references. I always wanted to improve my wand work! 🙂
This weeks project is getting the noise out of an audio power amplifiers outputs. It is a four channel unit made up of two stereo ones. Their crystal controlled clocks in my sample differ by 200 Hz. In a 1000' cable run the heterodyne result can be an issue. I guess I need a better wand and some more skill.
It actually looks like progress is being made! It used to be folks would offer the wisdom that the resistance of the power wiring all the way from the power plant to your personal wall outlet would swamp that of the cord.
Now folks are at least looking at the power cord as a filter.
There are three main issues;
The voltage losses from the cable and connections.
The ability to suppress noise coming in.
Prevent noise going out.
The first issue is easily handled by decent construction. I have seen power cords that are nice and thick, but it is all plastic mot copper. Actually not even good copper as a magnet sticks to it!
The second issue can be a big deal for preamps A/Ds etc. once noise gets into the enclosure it is no longer a simple matter to prevent it from making it into some place where it hurts.
The third is more of an issue for power line noise sources such as audio power amplifiers.
As to your old Stax box, it probably was designed when there were fewer noise sources and the issue had not yet been recognized.
There really are easily done measurements that show the effects of line noise, little magic involved.
George,
Thanks for the references. I always wanted to improve my wand work! 🙂
This weeks project is getting the noise out of an audio power amplifiers outputs. It is a four channel unit made up of two stereo ones. Their crystal controlled clocks in my sample differ by 200 Hz. In a 1000' cable run the heterodyne result can be an issue. I guess I need a better wand and some more skill.
Thank you for responding.
I would really love seeing such a speaker on the market.
Following your posts I have understood how knowledgeable, cautious and critical you are with speaker design and performance.
George
On a slightly different note: at the weekly flea market in my home town, I spotted some cables that looked like balanced interlinks, with (gold plated pins!) Neutrik XLRs at the ends. The yellow/beige cable color looked vaguely familiar.
Upon inspection I saw the labeling on the 6 foot (1.82 meters) long cables:
Van Den Hul C.C. The Second Halogen Free .
I know this cable, used to retail for 200 or 300 bucks a meter.
How much? One Euro. Both? No, each. Well... OK.
Such is the short lifespan of fame.
Jan
Upon inspection I saw the labeling on the 6 foot (1.82 meters) long cables:
Van Den Hul C.C. The Second Halogen Free .
I know this cable, used to retail for 200 or 300 bucks a meter.
How much? One Euro. Both? No, each. Well... OK.
Such is the short lifespan of fame.
Jan
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This is the HF noise from the amplifier before and after a simple ferrite bead filter.
Third image is the amplifier feeding audio to an 8 Ohm resistor through 1000' of cable.
Actually hard to measure as the other channels spray a lot of noise.
Now all I have to do is wind another 62 beads.
Third image is the amplifier feeding audio to an 8 Ohm resistor through 1000' of cable.
Actually hard to measure as the other channels spray a lot of noise.
Now all I have to do is wind another 62 beads.
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- Power cords- If your system has 1 power cord its performance may not matter too much. No audio system beyond a Bluetooth speaker is likely to have a single power cord. Lay out the matrix of boxes and cabling with all the parasitics and then you may see more obvious reasons for differences. And why a fully characterized power cord may not be enough. Shielding may just add leakage current paths.
There are military standards for this stuff (MIL-STD-461 and Tempest) since spooks have figured out how to extract intelligence info from the noise on the power cord. Its one of those wonderful standards where they don't tell you what to meet, just that you didn't. (Apple works this way as well.)
More: Tempest Line Filters | RFI Filter | EMI Filter | Power Line Filter | Curtis Industries Electrical Components Manufacturer
"TEMPEST is an acronym for Transient Electro Magnetic Pulse Emanation Standard. A tempest filter eliminates conducted EMI (Electro Magnetic Interference) information. Most electronic equipment inadvertently emits EMI emanations, which could be constructed into useable data if picked up by a skilled electronics expert. Some commonly compromised sources of information include telephone signals, personal computer data, server information, and countless other sources. Simply put, data is constantly being leaked through power lines and almost any other outlet that transmits electronic information. A tempest filter protects your sensitive data (commonly referred to by tech junkies as “red” data) by filtering information across a much wider range of available frequencies than other standard filters."
However any product with a clock over 32 KHz needs to be tested to pass FCC to be sold in the US and all of this stuff is tested. I think you can see the conductive emissions reports online. https://apps.fcc.gov/oetcf/eas/reports/GenericSearch.cfm ? But that would be science and we know scientists don't know anything.
There are military standards for this stuff (MIL-STD-461 and Tempest) since spooks have figured out how to extract intelligence info from the noise on the power cord. Its one of those wonderful standards where they don't tell you what to meet, just that you didn't. (Apple works this way as well.)
More: Tempest Line Filters | RFI Filter | EMI Filter | Power Line Filter | Curtis Industries Electrical Components Manufacturer
"TEMPEST is an acronym for Transient Electro Magnetic Pulse Emanation Standard. A tempest filter eliminates conducted EMI (Electro Magnetic Interference) information. Most electronic equipment inadvertently emits EMI emanations, which could be constructed into useable data if picked up by a skilled electronics expert. Some commonly compromised sources of information include telephone signals, personal computer data, server information, and countless other sources. Simply put, data is constantly being leaked through power lines and almost any other outlet that transmits electronic information. A tempest filter protects your sensitive data (commonly referred to by tech junkies as “red” data) by filtering information across a much wider range of available frequencies than other standard filters."
However any product with a clock over 32 KHz needs to be tested to pass FCC to be sold in the US and all of this stuff is tested. I think you can see the conductive emissions reports online. https://apps.fcc.gov/oetcf/eas/reports/GenericSearch.cfm ? But that would be science and we know scientists don't know anything.
you need to open paint, set the image size to 40x40, close paint, then each time you open it the default will be a small blank square, but any larger image pasted in will auto size to whatever you paste in with no spare whitespace, makes it easier when you paste from a single application with control-printscreen.
Digital equipment is greatly affected by relationships to enclosure ground. So compared to an amp a shield may be a big diffefence, and so may be how the ground wire is woven/twisted into the pattern. You also take into account mutual induction and how much RFI a cable if grabbing from the air. Generally speakering you can get away with higher capacitence in power cables than signal so you have some mode elaborate patterns avaliable.
I don't believe most power cables are legit, but given the amount of ways to manipulate its no surprise they can sound different, for better or worse.
In the medical field ferrite beads also don't stop a defib machine from working. But in the audiophile/recording world they will stop someone from listening most of the time; they are NOT easy to implement with favorable results.
Ferrites may have a little hysteresis that generates a little noise, but so do power transformers, although the spectrum may be different.
Or maybe use something like the freeware utility Irfanview: IrfanView - Official Homepage - one of the most popular viewers worldwide
I find it a lot more useful than Paint.
Similarly, Notepad++ is an excellent and powerful replacement for Notepad.
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