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I noticed this tonight on the BPT upgrade page:
It's at the bottom of the page. I couldn't find any mention of it in the AA archive, and I don't recall seeing such a product before. Has anyone ever used or made something like this? If so, how much of an effect did it have?__________________
Follow Ups:
the earth or screen of the cable itself ? I cant see how its going to work.
If the jacket is intended to improve the shielding, then it will have to be connected to earth somehow. This will increase the capacitance and may do more harm than good, but it might also be a net benefit.However, if it is to absorb energy from standing waves on the cable, then it can remain floating. The energy is dissipated by internal conduction mechanisms that respond to induced emf from the standing wave's electric and magnetic field components. No connection to earth is needed.
The drawback is mechanical vibration in the jacket. A floating conductive jacket that vibrates will inject electrical noise by the same coupling mechanisms working in reverse. Acoustic damping will help this problem.
My understanding of electrical theory is certainly lacking, but would the physical barrier itself not provide some amount of RFI shielding by way of reflection or absorption, even without being able to drain to ground? Is the Acrolink housing part of the ground circuit?
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A grounded metal sleeve the same dimensions would be a shield for radio noise up through the microwave bands. A floating object just causes the fields to be deflected, and if the wavelength is much longer than the longest dimension of the object, the changes in field shape are minimal.Where this device is useful is in dissipating RF energy rather than reflecting or deflecting it. Most power cords support standing electrical waves. Since they are made from low-loss materials (good conductors and good insulators), their resonant 'Q' is quite high and a little external RF noise energy that covers the resonant frequency of the cord will excite a strong tone on the cord.
This is similar in concept to an organ pipe. The input energy is the turbulent motion of air across a sharp edge at one end of the pipe. The pipe tone is quite loud compared to the actual sound of the turbulent air because of resonance in the pipe.
The sleeve here contains carbon fibers, which act as resistors to dissipate energy from the electric field component of the standing RF waves. This lowers the 'Q' of the cord and reduces the strength of the resonant tone. It does not block all background RF noise from the system, but that noise is a much smaller problem than the resonance.
Hi AlThe dissapaiting resistor effect of the carbon fibres would only work if there is an electrical circuit formed (unless its is relying on the impedance of free air to accomplish this task) i dont think the capacitive coupling from the screen of the cable to this after market sleeve (only a few pf in my guestimate) would be accomplish this , but as always i might be wrong.
The capactive coupling to the wires inside the plug would also be very small given the distances involved ( <50pf at a guess)
I agree the mechanical damping effect might do something but so would anything wrapped around the cable including plasticine or a bandage.
We are not dealing with circuits at these frequencies. The standing waves on a cable extend into the space around the cable to some extent, and as much as the electric field extends to where the carbon fiber is placed, it will dissipate energy into the fiber.A dark object gets warm in the sun, and it is not connected to the sun by a circuit.
This brings up a good point, though. There are two basic types of standing waves. The normal mode waves comprise voltages between individual conductors (including any shield). The common mode waves comprise voltages on all conductors acting as though they were a single conductor. The external carbon fiber damping arrangements work best on the common mode waves, since the electric field extends radially into space around the cable.
External carbon fiber arrangements do not work as well on the normal mode waves. Some sort of circuit is required to dissipate energy from them. I've found that composite R-C networks, where a series of capacitors of different sizes is used, can reduce the effects of normal mode standing waves without loading the cables in the audio band.
I had the impression that RF was the main culprit that needed to be addressed. Thank you for disabusing me of that notion, LOL, and for your clear explanations in this thread.
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............"Where this device is useful is in dissipating RF energy rather than reflecting or deflecting it."If the CF sleeve dissipates RF that is radiated from the cord, would it not also scatter RF that bombards the outer surface of the shell?
"This lowers the 'Q' of the cord and reduces the strength of the resonant tone. It does not block all background RF noise from the system, but that noise is a much smaller problem than the resonance."
Could one surmise that in addition to the CF, the machined aluminum housing would mitigate the "Q" of the cord even further and could possibly be "tuned" to the "Q" of the cord with it's mass? A mechanical notch filter maybe?
Also, how would the CF barrel and say a CF wall plate such as the Oyaide WCP-Z combine to dissipate RF? Could they be thought of as "opposing barriers"? One from the cord side and one from the outlet side?
TIA and cheers,
An aluminum sleeve would also have mechanical resonances, which would have to be dealt with separately. As a good conductor, though, it would reflect RF.Carbon fiber in an area where the standing waves have high values of electric field will dissipate energy from the standing waves. Thus, a CF wall plate will complement a sleeve containing CF to increase the dissipation for standing waves on the cord.
I don't know the relative balance of CF and conductors in the subject sleeve, so I don't know whether it would mostly reflect or absorb energy. I believe a sleeve made mostly of CF would absorb the energy that reaches it. It looks black to visible light and would look black to radio waves. This is similar in concept to stealth aircraft technology.
"My understanding of electrical theory is certainly lacking, but would the physical barrier itself not provide some amount of RFI shielding by way of reflection or absorption, even without being able to drain to ground?"The Carbon Fiber barrel will shield RF from entering around the connector. Al is more adept at explaining this aspect of the connectors performance than I.
The machined aluminum housing will mitigate parasitic resonances much better than molded plastic which IME imparts a monotonous quality to the resultant sound especially in the low frequencies.
" Is the Acrolink housing part of the ground circuit?"
No. It has no electrical connection to Earth Gnd.
"The machined aluminum housing will mitigate parasitic resonances much better than molded plastic which IME imparts a monotonous quality to the resultant sound especially in the low frequencies."That's an interesting observation. Did you determine that by comparing plastic-housing plugs to the Acrolink, or maybe by trying some sort of mechanical dampening on plastic housings?
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I first made the observation when I was utilizing Marinco AC plugs in my system.I first removed the outer barrel from the plug and briefly used it in that state and found that the whole audio spectrum became more focused, especially the bass, which portrayed a better sense of agility.
I then played around with dampening the barrel of the Marinco with Oatey's plumbers putty and that improved the audible focus but was too messy.
I then removed the blades and the GND pin from the plug body and safely soldered them to the power cord. I covered each connection in heavy duty heatshrink and plugged it in and sat back.
Holy #@$%!! THAT was a real ear opener as it completely transformed
the audio presentation from top to bottom but it was in the bass range that it had the greatest impact. It also spread the soundstage out quite a bit and greatly improved PRaT.Since the PC with no plug body/barrel is not what one would consider safe, I tried an Oyaide P-079 from recommendations here and was surprised that it came very close to matching the sonic presentation as the cable without the plug body and from there, my AC obsession really took off.
Cheers,
But I guess it IS the only way to isolate the plug body's effects. Thanks for sharing the info.
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Al Sekela and I have experimented with and reported here about carbon fiber cloth sleeves on plugs. They work to reduce RFI in our systems, and they might just do the same in yours. It's a quickie way to mock up what Acrolink is doing (in part of course) at low cost, and it's reversible too.
Here's what Chris Hoff emailed me about it:"The plug shield is comprised of brass, copper, nickel and carbon fiber and simply slips over existing plugs. Yes, they are available at $25/pair. The plug shield stays far enough away from the plug contact spades so that capacitive coupling is minimal (.002pf increase--using a pair of shields)."
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That description fits the bill. This product now sounds like the real deal and I'm interested!As I posited, carbon fiber, but the metallic ingredients (at least the copper and the nickel) are also proven RFI dampers/shields. In fact, this combination sounds to me like it has the same theoretical benefits of 2 actual products known to work well: Power Wraps (I suspect the metal they are made of includes copper and nickel, plus others) and carbon fiber sleeving.
According to the theory posted by Al Sekela (and proven in my home system to my satisfaction), the key places for these dampers are: terminations, center area of the cord, secondary nodes along the cord length. Particularly for carbon fiber the terminations.
So this tweak should do what it purports to do and you might be surprised at the nice results if you use them on multiple cords. RFI tweaks are cumulative.
Truth be told, I could mock up the CF sleeving easily for under $10 for the pair, but I would be hard pressed to make up the whole package for under their price of $25/pair. So it now looks to me like a good deal on a good item. YMMV, of course.
Damping standing waves requires use of the appropriate materials at the right locations.Generally, the electric component of a standing wave is always maximum at the ends, no matter what harmonic of the fundamental, as long as the end is terminated in a higher impedance than the cable characteristic impedance. Carbon fiber is useful to absorb energy from the electric field.
The magnetic component is always maximum at the center of the cable under the same conditions, so a Power Wrap is useful at the center.
Both types of materials are useful at the electric and magnetic maxima for harmonics of the fundamental, so covering the entire cable with both carbon fiber and Power Wraps will dampen all the harmonics as well as the fundamental. This is one case where it is true that if a little damping is good, more is better.
Putting carbon fiber at the ends and a Power Wrap at the center will dampen the fundamental ringing tone and some energy of the harmonics. Extending the coverage is expensive and cumbersome, but improves the cable performance by improving the damping of the higher harmonics as well.
Al, I count on you chiming in with the correct theory. I'm only good for tinkering and reviewing, when you get right down to it!Anyway, this product sounds as though it should work reasonably well, and if it's what they say it is, I would have a hard time beating their price by all that much, much less doing it as neatly as they do...
Of course, being of the beer pocketbook tribe, you know I will now try to do just that.
I agree....I would have suggested ERS for a little more bandwidth, but your in the right area. But from a marketing aspect I can't imagine a carbon fiber plug sleeve for $25...you know as well as I do that carbon fiber is not cheap, especially when you have to add the insulation, logo, etc...no room for mark up. Now on the other hand if the sleeve is insulated ERS, then I can see the mark up. Each shell requires 5.25" (for a sleeve...5" for a wrap) x 2" of ERS. Even at list price ($19.95) that is 8 sleeves at $25 bucks a pop....that is $200 per sheet minus $20 bucks for a 4' tube of adhesive lined heatshrink. Now on the other hand if he used the standard cloth EMI paper, then you can pick 8" x 10" sheets for like $5 bucks a pop. This stuff here is basically the non-audiophile version...same stuff (coated carbon fiber)...just a different pattern layout.
I'd use the sleeving that is usually resined into rods. It comes in various diameters and right now I could get a foot of 2" sleeving for under $2 - that's about 4 sleeves at least. The resin is rather cheap. Then just use a standard plug as the "mold". All rather simple technology.For kicks I could also line it with carbon paper (thank you Moray James) or your EMI paper.
And IME this type of sleeve does work and delivers the benefits stated.
Soooo, tell me more about the EMI paper and where you buy it, Alan.
Enjoy!!!: http://www.lessemf.com/I would love to try one of your sleeves.
"Has anyone ever used or made something like this? If so, how much of an effect did it have?"Hhhmm, certainly looks interesting and at only $25 a pair, why don't U procure a pair, try them, and report back to us as to their effectiveness? In other words, make an informed decision for yourself :-)
On the surface, it appears these R a low cost version of the Acrolinks which utilize aluminum and carbon fiber for the outer barrel of the AC plug/IEC inlet.
Cheers,
I mean no disrespect, but you are reaching. The B-P-T cable shield looks like a 3" piece of 1 1/4" conductive heatshrink. I suggest you try something like that first before sinking $25 bucks into the cable shield. Besides....all it's going to do is raise the capacitance at the ac plug...sometimes that works and other times it doesn't. It all depends on the amount and type of filtering used throughout the system.Check out Cablepros for conductive heatshrink.
Doesn't "appear" to be heatshrink from the image but who knows.$25 is nothing to procure one to asses the product and it's merits and one could also try the conductive heatshrink U mention for comparison purposes and report back here to us.
I mention this as it seems only a few of us are willing to procure new/interesting products/tweaks, evaluate them, and report back to the Asylum community on the products merits or lack thereof.
Cheers,
If I thought my current power cords were resolving enough to benefit from this tweak, then I would have tried it for myself. As it is, it's yet one more untried tweak that I'm filing away for future reference, until such time as I believe my system will give me an accurate indication as to the tweak's effectiveness. If your sensibilities are so imposed upon by my asking the board for opinions, perhaps you should have just avoided replying to my post.
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"If I thought my current power cords were resolving enough to benefit from this tweak, then I would have tried it for myself."Obviously, your system needs further attention since U already doubt your own PC's. Get it right to begin with from the wall and THEN start to fine tune with products such as the sleeve.
"If your sensibilities are so imposed upon by my asking the board for opinions, perhaps you should have just avoided replying to my post."Get over yourself Todd. There are only a few of us in this asylum who actually buy products and report back about their validity BUT we have also refined our system(s) to the point to make an informed judgement.
If U don't like my response to your query, U R certainly welcome to retort as U deem necessary but that will not, in ANY way, mitigate the fact that more people need to "step up to the plate" and add meaningful substance to this asylum by way of their own experiences.
Take a risk and buy a product that sparks your interest. Ask for other peoples experiences with said product but the ONLY way for one to make an informed decision is to have first hand experience with said product in their own system. Buying products just on a recommendation from others is a sure recipe for disappointment most of the time.
I have a very strong interest in products that effect AC delivery and I am more than willing to buy products aimed at addressing AC delivery issues and share those findings with my fellow inmates and yes, that includes U....Todd :-)
Stepping down from my soapbox now.Cheers,
~kenster
...for simultaneously pointing out, and missing, the obvious. If we all shared your socio-economic status and spending priorities, things would undoubtedly be easier for you to understand. I suppose that why other people might be unwilling to share their experiences and curiosity on this board, and thereby subject themselves to the banality of others, shall remain a mystery to you.
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..........your psycobabble bullshit is getting U nowhere."..for simultaneously pointing out, and missing, the obvious. If we all shared your socio-economic status and spending priorities, things would undoubtedly be easier for you to understand."
It is U who is being blinded by your own ignorance. A persons spending priorities can only be determined by that person and the financial situation they have put themselves in.
"I suppose that why other people might be unwilling to share their experiences and curiosity on this board, and thereby subject themselves to the banality of others, shall remain a mystery to you."U and your ilk R the very reason why people are hesitant to even poke their heads in here. I choose to participate in this forum as it has great interest for me and I am willing to share my thoughts on products I have tried and maybe even learn something by keeping an open mind. U seem to be nothing more than an antagonist unwilling to even entertain ones viewpoints if it is not within your budget or it doesn't fit in your cozy little comfort zone.
I understand....and I meant no harsh feelings by my comments. I don't know if I would have compared the shield to a carbon fiber product because the noise suppression and ringing suppression is not the same by a large scale, but as a suggestion, you might want to try wrapping the ac and iec shell with a single layer of Stillpoints ERS and compare against a carbon fiber plug. ERS will offer you the closest comparison in noise and harmonic suppression. ERS can get a bad rap if used in the wrong application, but it's fantastic used in a/c applications. I use it to wrap circuit panels in custom jobs that I do for recording studios. It does a nice job of lowering crosstalk between circuits and lowering ac wiring harmonics.
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