Protect Yourself From Dirty Electricity - Greenwave Filters warning the FUD is high on this website, but at least they only charge $25 for their filters and only $150 for the 'meter' to show how crappy your mains are. But the health effects page is enough to make you want to move off grid if you believed a word of it.
I have posted a few times that I have used a similar test method and have suggested that others try it.
Take your very long unscreened twisted pair input cable (from your attenuated Source to your Power Amplifier) and pass it near and over and around the mains transformer that is powered up with an unscreened twisted triplet input cable (primary feed) and an unscreened twisted triplet output cable (secondaries) feeding the power amplifier.
Listen to and/or measure the changes in Hum/noise at the power amp output.
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I can not comment on advertising practices of that company but I can say that I am not paid by them and I have several meters of their loudspeaker cable that I am using as a mains cable. My comment is based on my experience. I like their loudspeaker cable much more as a mains cable than as a loudspeaker cable. No doubt that companies would do many things to promote their products but in this particular case it is more like the case where perception of some listeners, and that includes me, was tried to be explained by an expert post festum, after it was experienced.
There is no doubt that the perception is experienced by some listeners but we can discuss if the explanation given by the expert is scientific enough.
But the guy who wrote that advertisement for them was. Integrity does not always withstand the lure of a paycheck. 😀
I admit that the report serves the purpose of promoting the product but denying the value of the report will not remove the perception. Or you suggest that I am not hearing what I am hearing.
Many years ago I took that cable mounted on mains distribution box and went to my friends recording studio. I asked him to connect the whole setup to my distribution box and to play again the same recorded excerpt without touching anything else. He was amazed how much cleaner the excerpt sounded by simply connecting mains using that cable.
In an environment full of electronic "smog" we should use all the help available to filter it no matter if we understand how it works or not. I am coming from humanities and I know that many things that exist can not be fully explained, but people from exact sciences think that the things that can not be explained does not exist.
Many years ago I took that cable mounted on mains distribution box and went to my friends recording studio. I asked him to connect the whole setup to my distribution box and to play again the same recorded excerpt without touching anything else. He was amazed how much cleaner the excerpt sounded by simply connecting mains using that cable.
In an environment full of electronic "smog" we should use all the help available to filter it no matter if we understand how it works or not. I am coming from humanities and I know that many things that exist can not be fully explained, but people from exact sciences think that the things that can not be explained does not exist.
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Depends on what you mean by "hearing" and if you have a particularly poorly designed/implemented device that you're using the power cord for.
If changing a power cord changed the sound of my system, I'd be burrowing into it to figure out which part I screwed up.
No, people from exact sciences delve under the surface to find an explanation. As SY says, it's perfectly possible to have something so bad that a 3ft mains cable makes an audible change, but that just means whatever its plugged into is so poorly engineered that it should be thrown in the bin. With mains power, doing things right is much cheaper than slapping a band aid on.
If the bling cable still makes a difference, then that is not something engineering can help with and you need a psychologist to explain that to you.
Many more things CAN be tested and explained.
Billshurv's power conditioner (quality one) ... has a 2 stage common mode/RFI
filter on FR-4 plus surge (gas discharge + mov). It will remove that "smog"
according to the L/C of the filter and save your equipment , as well.
(some even have insurance included) ... 🙂
PS - WAY better investment than fancy cable.
Andy T's twisted triplet "trick" was tested by me. Using a industrial current sensor ,
radiated AC was 1/10th at the output with the sensor. The sensor was designed
for just one wire. You carry this cancellation principle out to the decoupling - amp
layout considerations (DC w/ripple) and a totally hum free amp is possible (even with less than
ideal wiring/grounding).
The "smog" comes through the wire WITH the AC - a braid/shield will not stop it.
Edit - you are just giving the "smog" a fancy path right into your equipment.
OS
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a closer look to the datasheet under
http://www.belden.com/techdatas/metric/83803.pdf
let raise at me the question, whether this cable type is ever intended as a mains power cord, although many suppliers like
http://www.ab-system.hk/index.php?route=product/product&product_id=120
e. g. it particularly suited as a highlight for this (Belden 83803 Audiophile Power Cord).
What are the comments from Belden itself to this application? And what recommend Belden concerning the connection of the outer screen ?
Maybe one of the members can find out this by phone - my English isn't good enough therefore.
Thank you.
http://www.belden.com/techdatas/metric/83803.pdf
let raise at me the question, whether this cable type is ever intended as a mains power cord, although many suppliers like
http://www.ab-system.hk/index.php?route=product/product&product_id=120
e. g. it particularly suited as a highlight for this (Belden 83803 Audiophile Power Cord).
What are the comments from Belden itself to this application? And what recommend Belden concerning the connection of the outer screen ?
Maybe one of the members can find out this by phone - my English isn't good enough therefore.
Thank you.
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No, it is not. It is a tray rated cable. There is a distinct difference.
edit: actually, it can be used in a tray, but is not limited to it. However, as it is article 760 cable, it is not defined as a portable cordage.
jn
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This is necessary if an open frame smps is used in an assembly and the mains cable also is laid inside.
Gajanan Phadte
http://www.diyaudio.com/forums/atta...high-power-solid-state-power-amps-efi-rfi.jpg
This schematic implies that the Neutral and Safety Ground are connected together near the filter.
This schematic implies that the Neutral and Safety Ground are connected together near the filter.
Pickup of what by what? Twisted power cables radiate (magnetically, capacitively or both) 50/60 Hz interference into adjacent sensitive signal circuits. They do not pick up anything. Twisting helps prevent such radiation substantially but not totally.
Do you mean their own enclosures? For power transformers it is as much a protective/aesthetic thing as anything else. For power supply chokes which mostly have a gapped core, such can radiate substantial magnetic fields at the gap. This is partly prevented from reaching magnetic field prone circuitry in the vicinity by the component's own magnetic shielding, and further interference by judicious lay-out. As said, such shielding is mainly magnetic, not capacitive as applies to shielded cable. (Yeees, OK! A magnetic cable shield might assist there. Is the shielding of such power chords magnetic material?)
Again, interconnects can carry low signal level, mostly in the 100s mV down to a few mV region. They are shielded against receiving pickup of surrounding interference of whatever nature.
By now you would have noticed that the specific purposes of shielding in your examples are very different! In some cases to prevent radiation, in others to prevent pickup, and always with respect to the sensitivity of said case's intensity/sensitivity. Thus your 'sweeping' generalised comparison irrespective of the above fails to have much meaning.
I intentionally made statements perhaps condescending, not to under-estimate readers' intelligence but to try show that applications are varied and condition-sensitive. At this point and as said by others, I fail to see the electrical implication of shielding a few meters/feet of mains input cable. Nobody has made the practical advantages clear (respectfully, not accepting anecdotal sensations as proof).
(Except to prevent it from radiating into said sensitive signal circuits? Yes, but one seems to be talking mainly of the power chord from the wall outlet to the amplifier. The lay-out and general shielding of a chassis make such the least troubling element.)
Power screen cable?
Twisted cables improve common mode rejection on the interference due to magnetic/capacitive coupling. This does not mean the signal inside cable are clean. The affecting signal passes in both wires and attached to the main signal. The common mode rejection happens only at the receiving end electronics which cancels them. To reduce magnetic interference, some sort of iron shielding between the cable and magnetic radiator is required. To reduce capacitive coupling keeping a distance between the twisted cable and radiator is necessary.
Power screen cables improve on static / capacitive / voltage interference. If the cable carries interference signals, it will not be radiated OR if the cable is near interference source it may not affect the cable.
If the cable carry interference signals, it will carry it from one end to another without radiating the interference. If the cable is 5 meters long, the interference signal is radiated before and after. These screened power cable are used for medical / instrumentation application where impedances in the order of 1000 mega ohms are used. In audio this is used by snake (oil) charmers.
Regards,
mandu
Twisted cables improve common mode rejection on the interference due to magnetic/capacitive coupling. This does not mean the signal inside cable are clean. The affecting signal passes in both wires and attached to the main signal. The common mode rejection happens only at the receiving end electronics which cancels them. To reduce magnetic interference, some sort of iron shielding between the cable and magnetic radiator is required. To reduce capacitive coupling keeping a distance between the twisted cable and radiator is necessary.
Power screen cables improve on static / capacitive / voltage interference. If the cable carries interference signals, it will not be radiated OR if the cable is near interference source it may not affect the cable.
If the cable carry interference signals, it will carry it from one end to another without radiating the interference. If the cable is 5 meters long, the interference signal is radiated before and after. These screened power cable are used for medical / instrumentation application where impedances in the order of 1000 mega ohms are used. In audio this is used by snake (oil) charmers.
Regards,
mandu
All cables into, or out, of an amplifier are potentially both receivers and transmitters of interference.
This interference can be at any frequency from mHz (milli) to GHz, not just 50/60Hz.
Twisting of cables reduces Loop Area AND introduces the canceling effect due to the averaging of opposite half turns, i.e. there is a doubling of the interference attenuation due to twisting of the Flow and Return parts of the cable.
AND I'll repeat: this does apply to ALL cables entering the amplifier box.
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A shielded power cable is an absolute must on most industrial gear containing switching power supplies, not to keep stuff from coming in but rather to keep stuff from coming out.
I have never been able to get a large industrial machine to pass CE certification, conducted emission, without one.
I have never been able to get a large industrial machine to pass CE certification, conducted emission, without one.
Means this, that in cases of use of power amplifiers, where SMPS inside, such cables are necessary for lower interferences with other components?
In the meantime a lot of power amplifiers without big 50/60 Hz toroidal transformers on the marked. Halcro (DM38) and Linn (Kimax) are examples.
Halcro dm38 power amplifier Page 2 | Stereophile.com
Anyone know which are the components of Klimax DS/1 are causing the improvements ?
Yes,
Jim Brown often writes on this topic:
"RFI, Ferrites, and Common Mode Chokes For Hams"
http://www.audiosystemsgroup.com/RFI-Ham.pdf
About 50 more Jim Brown papers:
Audio Systems Group, Inc. Publications
************************
Henry W. Ott also touches on this topic in his book:
"Electromagnetic Compatibility Engineering"
EMC Books
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