|   Critique of Video Cable Tech Article | Jon
Jan 2, 2003 10:16 PM | | This is a critique of the article by Steve DellaSala, "Component Video Cables - The Definitive Guide" at the Audioholics website:
http://www.audioholics.com/techtips/audioprinciples/interconnects/ComponentVideoCables.php
This article has been praised by some as "great", and touted as the last word on video cable issues. Well, I read it, and noticed a lot of questionable portions in the article. I quote some of these, and respond here in this post. Note that I have not necessarily picked out all the problem spots, just some that I have found to be sticking out more than others.
All of this post constitutes my own personal opinion, and is based on my understanding of cable issues.
Section 1.0, toward the end
[ There are a number of concepts and misconceptions about component video cables that will be addressed in this article, many of which will be proved or disproved mathematically. ]
Only, he does not show the math for a great many of the things he writes about, instead, he states it as if it were a given. Some of the math is only indirectly related to the subject at hand, or may be totally irrelevant.
Section 1.1, toward the end
[ Cable lengths less than 30 meters have no effect of overall impedance. ]
This is not necessarily true, and in any case, is contradicted later in the article.
Also, he goes into characteristic impedance formula's for infinitely long cables (Section 1.2), but have already stated they are not relevant. ???????
The whole impedance section is confusing and self-contradictory.
Sec. 2.0
[ Furthermore, strand jumping is another made up term used by manufacturers to justify using less expensive
solid conductor wire for their cable assemblies, as discussed in Section 3.1.1. ]
I am not aware of any manufacturer that uses strand jumping in extolling the virtues of their video cables.
With this in mind, I find it odd that this would be mentioned in an article on video cables, if none of the manufacturer's make any such claims.
Strand jumping has been brought up for analog audio IC's by a few manufacturer's, but not very many.
Also, this is the first place that mention is made of "solid wire costs less to manufacture than stranded wire" for video cables. This is so mis-guided and ill-informed, I can not begin to make any sense of it.
While there may be a very slight premium to use stranded wires in a coaxial cable, the cost difference would be SO slight as to defy any logical reason to base a design on that cost factor, the mere fact of having a custom cable made would completely obviate any reasons for doing so, virtually no significant cost difference for solid vs. stranded once we are talking about custom cables.
See: "The Cost of High End Audio Cables"
http://www.AudioAsylum.com/audio/cables/messages/34038.html
for a bit of an explanation on this.
Additionally, I have spoken with more than one RF engineer who was adamant that solid wires made for better coaxial cables for RF purposes, as the stranded wires could "spread" when the cable was flexed, and move within the insulation, and a solid wire would not do that as much. They also preferred a solid insulator to a foamed one for the same reasons. I doubt that it would be as much of an issue for the really stiff foamed insulation's, such as foamed FEP teflon, not nearly as soft as foamed PE, etc.
See:
http://www.gepco.com/whatsnew/pr_050102_HDfoamcoax.htm
for an article on making Hi-Definition coaxial cable for HDTV.
Note that the article was published in "Broadcast Engineering" magazine.
This web site says that solid wire coax has less losses than stranded wire coax:
http://tcns.thaicom.net/RF/Coax.asp
SEC 2.1
[ ....or a poorly made component video cables are used that are not true 75-ohm, the lower impedance value of these cables can result in a loss of video signal do to a mismatch in impedance. ]
This statement is not precise enough to be able to comment on very much, e |
| re: Critique of Video Cable Tech Article, Part 2 | Jon
Jan 2, 2003 10:18 PM | | Part 2
This statement is not precise enough to be able to comment on very much, except that it gets repeated in other forms later on. Impedance mismatches will not cause an overall level drop, nor will they cause a loss of the video signal as a whole. What an impedance mismatch WILL do, is to cause partial signal reflections that bounce back down the line. Some if this is ALWAYS going on in any RCA plug based video cable, so it is really a matter of degree. Proper impedance cables can help minimize the amount and severity of these reflections, but will not eliminate them. More on this later.
SEC 2.3
[ Mismatched impedance is one of the most common and most frequently experienced sources of signal degradation. This phenomenon occurs when a 75-ohm signal encounters different impedances through its signal path, usually on the order of 35-ohm or 50-ohm for Home Theater applications. It can occur in video cables that do not use true 75-ohm RCA connectors, .... ]
Well, that would be great, except that there is no such thing as a true 75 ohm RCA phono connector! More on this later, in response to section 3.5
Also in section 2.3, we are lead through a series of equations, but what he fails to point out completely when discussing the equations, is that the signal losses due to reflections will tend to occur ONLY at certain frequencies related to the effective electrical length of the cable, and will NOT affect ALL frequencies the same. It is entirely possible that for a short cable (2M or less), NONE of the frequencies carried by a video signal would be affected by any of the reflections, unless they bounced back and forth many times.
In order for this to occur, there would have to be impedance discontinuities at both ends of the video cable, and they would have to be fairly severe at both ends.
SEC 2.4
[ Skin effect is sound engineering phenomenon that can be defined mathematically, however as outlined in the following examples, it has minimal effects at low frequencies within the range of audio and video cables. ]
This section is also written in a very confused manner.
First, we are lead to believe that skin effect has no consequence, yet, in the first side bar "Pursuing the Truth", we are told that: "When a copper conductor is plated with pure silver with a thickness of 50 microns, 92% of the current density will be in the silver. Since silver has a 10% gain in conductance compared to copper, a copper wire plated with silver will have less signal loss especially at longer lengths, thus minimizing skin effect."
So which is it? Can skin effect be ignored, or it is a factor, and silver plating will reduce it? He seems to be saying both things.
Later on in this section, he talks about the increase in AC resistance that skin effect causes, and later the power loss from skin effect.
However, these two kinds of losses are not the only effects that result from the skin effect, phase shift also occurs, and skin effect is responsible for forcing the current out toward the surface of the wire, even at audio frequencies, much less video. So skin effect DOES make the surface of the wire more important than the rest of the wire, and the condition of the surface of the wire, in terms of impurities, or poor metallic crystal structure, are going to have a potential effect. None of these aspects is even considered or brought up.
Finally, it is said that the frequency ranges of video (and audio, once again, trying to squeeze in a subject that is not the avowed topic of the article) is not subject to skin effect.
Well, at 20 kHz, the skin depth for copper is 0.46 mm, or about 5/64's of an inch. The diameter of a 19 ga wire would have this depth at the center of the wire, and while this kind of assumption is often made for what size wire will be "free" from skin effect, it is just another way of providing a benchmark for comparison. Most folks who have worked with audio cables find that a 19 |
| re: Critique of Video Cable Tech Article, Part 3 | Jon
Jan 2, 2003 10:21 PM | | Part 3
Most folks who have worked with audio cables find that a 19 ga. wire has problems, and that smaller diameter wires are needed to avoid audible problems, whether they are due to the skin effect, or other issues.
One can certainly see that there will be some significant skin effect at video frequencies for any reasonable size of coax center wire, even RG-59 types with a 20 or 22 ga. center wire.
End of SEC 2.4
[ Pursuing the Truth: Most cable vendors use multi stranded wire as opposed to solid core conductor. Multi Stranded wire actually helps to reduce skin effect since the combination of strands act as a larger surface area then an equivalent gauge solid core conductor. ]
The amount of increased surface area for a stranded wire is NOT that much greater, as the skin effect will still manifest on the stranded wire bundle AS A WHOLE. The individual wires WILL NOT each act independently unless they are BOTH individually insulated, AND woven in and out. This kind of wire is called Litz wire. I know of no vendor that uses a Litz wire for the center wire.
The only increase in surface area that a stranded wire has is due to the extra area of the rounded outside edges
of the stranded bundle. This is not a huge increase in surface area, since the skin effect is still pushing the current out toward the surface of the bundle as a whole.
You might see a 10-15% increase in conductivity for skin frequencies, due to stranded wires vs. a solid wire of the exact same overall diameter as the stranded bundle.
Yet again, what is the big deal if skin effect is not an issue in the first place? Either it IS relevant, and stranded vs. solid and silver plating vs. bare copper are then relevant, OR they are a moot point.
Doesn't this sound exactly like the very snake-oil they rankle about? Touting certain features (stranded wires, and silver plating) as relevant, even though they say in the same breath, that it doesn't really matter according to the calculations?
BTW, as for "Most cable vendors use multi stranded wire...", I am not sure this is actually true for video cables, it certainly may be for audio cables. However, this article was supposed to be about video cables.
SEC 2.4, 3rd "Pursuing the Truth" sidebar, 3rd section, where they talk about terminating the cable.
The pictures at the bottom of the 3rd page in the article ( http://www.audioholics.com/techtips/audioprinciples/interconnects/ComponentVideoCables_3.php )
are used as examples of a "good" solder connection, and a bad solder connection.
In my experience, what constitutes a good solder connection for RF is a nice smooth, even solder profile, with no sudden discontinuities. The wire or braid solder joint surface should smoothly "flow" into the connector termination, with no kinks or sudden bends or large blobs of solder.
Based on that criteria, the cable on the right is not so bad, it could be improved on, but it makes no really awful mistakes. It may look superficially less than tidy, but the main concepts regarding solder joints for RF that I am talking about have not been badly violated.
No, it is not good to melt the insulation, but when we are already in the region of the termination, the exact spacing is not being maintained anyway, so this is being rather anal about the subject.
I note with interest, after all the talk about impedance matching, and proper soldering technique, they use as an example of a "good" RCA plug, one that has a built-in impedance discontinuity. Note the half open inner barrel section, where the area for soldering the center wire is open. This section is a different diameter than the rest of the barrel, and so, MUST present a different impedance than the rest of the barrel. So much for being truly concerned with all of the details.
SEC 3.1
[ For component video cables, the conductor is usually made with stranded wire for improved flexibility and increased surface area. ]
We have al |
| re: Critique of Video Cable Tech Article, Part 4 | Jon
Jan 2, 2003 10:24 PM | | Part 4
SEC 3.1
[ For component video cables, the conductor is usually made with stranded wire for improved flexibility and increased surface area. ]
We have already dealt with the "increased surface area" myth promoted in this article. But there is an even bigger gaffe to come:
[ The use of different materials for the primary conductor becomes apparent with video cables above 10 meters, as signal losses increases due to conductor resistance. ]
Increased conductor resistance is not really the primary reason for losses in a coaxial cable at RF frequencies.
As was pointed out earlier, RF tends to travel on the surface of the conductor, and so, the absolute gauge of the wire has little to do with these types of losses.
While the video signal is not, strictly speaking, RF energy, it will not have the kinds of signal losses due to sheer cable resistance that is implied here.
Then again, according to this article, all we have to do is silver plate the wire, and no more fuss!
Much of the loss in a coaxial cable at RF frequencies is due to dielectric losses, and a superior quality dielectric will minimize these losses.
So what about baseband video signals that are not RF?
Just as a point of information, the losses for a 100 feet of high performance cable at 10 MHz are: for an RG-59 (with a 22 ga. center wire) are 0.9 dB, for an RG-6 (18 ga. center wire) the losses are 0.7 dB, and for an RG-11 (14 ga. center wire) the losses are 0.5 dB.
This compares similar construction and materials, so as to eliminate as many variables as possible, except center wire ga.
These are very small differences in signal losses, and the actual materials and construction can often make more of a difference than the wire gauge. RG part numbers are not that specific, see:
http://www.AudioAsylum.com/audio/cables/messages/25155.html
In the "Pursuing the Truth" sidebar:
[ Consequently, cryogenically freezing the cable does not slow down or prevent oxidation either (unless it remains in the frozen state). The process itself only produces a temporarily cold cable. Once the cable is warmed, it is the same cable it was before being frozen. ]
While this may or may not be true for the oxygen free aspect, most of the folks who cryogenically treat the cables do not necessarily do so to improve the oxygen free content of the cables, rather, they are doing it to try and improve the crystalline structure of the metallic conductors. Metallurgy has shown that some sort of an effect does take place in many instances when a metal is cryogenically treated, so to say that nothing has changed is a bit much to be saying without any further qualification.
I have never seen any claims about cryo treatment being for the purpose of improving or maintaining the oxygen free aspect of the copper conductors. This would seem to be a red herring brought up to discredit cryo treatment without actually discussing the relevant issues associated with cryo.
SEC 3.1.1
"Pursuing the Truth" sidebar,
[ Be forewarned that some cable manufacturers use a solid conductor primarily for cost purposes. Through their clever marketing schemes, they use made up terms such as, "Strand Jumping". By using this made up term, they attempt to justify the use of less expensive coaxial cable for their component video cable assembly, ... ]
I have already dealt with the cost bugaboo, so now let us address the strand jumping issue here.
Skin effect, you remember, that non-issue effect that was reduced by stranded wire (false) and silver plating (somewhat)? Well, if the current in the wire, the actual electron flow IS the current, is forced toward the outside of the wire, then what happens when a stranded wire is not perfectly aligned all along the length of the stranded bundle? Some of the strands will be on the outside, and then end up on the inside of the bundle.
In order for that strand of copper that was carrying the HF currents while on the s |
| re: Critique of Video Cable Tech Article, Part 5 | Jon
Jan 2, 2003 10:27 PM | | Part 5
In order for that strand of copper that was carrying the HF currents while on the surface to follow the skin effect current density profile, it HAS to "hand-off" to a strand that is nearer the surface of the stranded wire bundle. The eddy currents that have formed and that are responsible for the skin effect in the first place, will cause this to occur. So skin effect WILL be instrumental in promoting some amount of "strand jumping" .
The various forms of stranding geometry as shown in the article will reduce the possibility of strand jumping, because if a given strand does not wander in and out of the overall bundle, but maintains it's place within the bundle, then there is less of an amount of skin effect current density differences to provide the impetus for any strand jumping to occur.
However, that does not completely eliminate all possibility of strand jumping, nor does it render the reason for it (skin effect) an inconsequential effect.
SEC 3.1.1
[ Resistance values of cables becomes significant in lengths well over 2-meters. If you are installing a custom Home Theater System and must run lengths of coaxial cable that greatly exceed 2-meters, component video cables made from higher gauge wire are typically recommended as they will have a lower resistance and therefore, will minimize video signal loss. ]
Well, now we are getting confused again. First, it was anything over 30 M, and I would argue about that.
But I can not possibly see how anything over 2M (about 6 feet), is going to need a huge RG-11 coax to avoid video signal losses! Totally off the wall, and inconsistent with earlier statements as well.
After pooh-poohing a 0.047 dB power loss due to skin effect, he is now saying that an amplitude loss of 0.04 dB (from RG-11 down to RG-59 for a 10 foot length at 10 MHz) is significant? Again, not consistent criteria here.
SEC 3.1.2
[ The grounding diameter is not related to the ohm
rating since in theory the ground does not carry a current. What is important is the ground shields ability to complete the circuit, protect the conductor to minimize signal leakage and shield the assembly from EMI. ]
Whoa! The coax braid does not carry a current? But in the very same section, he says that the braid completes the circuit! Well, which is it?
I can tell you, the 'shield' braid is the ground return, and does indeed carry current and complete the circuit.
See:
http://www.AudioAsylum.com/audio/cables/messages/503.html
for more on this.
SEC 3.1.2
[ By using two 95% copper braids, the amount of copper is substantially increased and the resistance therefore decreased, thus reducing the chance of current flow and noise in the cable. ]
Whoa ! Again! Reducing resistance does not reduce the current flow, in fact, it reduces the voltage potential between two video components by lowering the resistance, which actually increases current flow in the braid.
SEC 3.3
Under the dielectric section, he fails to mention that teflon also comes in a gas-injected/foamed formula, and would have dielectric constants as low or lower than GI/foamed PE, all other things being equal.
[ As seen by their constants, neither Nylon (4.0 to 4.6) or PVC (3.0 to 8.0) make effective dielectrics for any cable length, yet they are still used by some component video cable Manufacturers due to their low cost. ]
In so far as I know, no one currently uses PVC (or nylon) for the dielectric in a video cable. PVC has not been in general use as an insulator in a coaxial cable for many years, and it would indeed be a travesty if someone used it for video cables. I am personally not fond of it for audio use either.
However, the implication is that some vendor out there IS using PVC, when in fact, this does not seem to be the case.
SEC 3.4
[ This method also preserves the diameter ratio of the dielectric and conductor at the end of the cable where it has been cut and soldered onto the conn |
| re: Critique of Video Cable Tech Article, Part 6 | Jon
Jan 2, 2003 10:30 PM | | Part 6
SEC 3.4
[ This method also preserves the diameter ratio of the dielectric and conductor at the end of the cable where it has been cut and soldered onto the connector housing, thus preserving the 75-ohm impedance of the cable/connector combination from tip-to-tip. ]
As has already been commented on, this is not the case, the portion of the RCA plug inner barrel that is cut-out for access to the center pin changed the diameter of the plug along half of the plug for that length. Why this is ignored, when much is made of smaller issues, is a mystery.
SEC 3.5, bottom of page 5
[ It turns out that the RCA connector on the left has the correct diameter ratios to create a 75-ohm connection, where as the one on the right is adequate for a 50-ohm connection such as that found in audio signals. ]
Whoa! This would be funny if it weren't stated in an entirely serious manner. Apparently, the writer has swallowed some manufacturer's hype about "true 75 ohm RCA plugs", which is ironic given that the avowed purpose of the article is to provide solid information about video cables, rather than to parrot what has been hyped.
Bottom line: no matter what the RCA plug itself is doing, the female RCA jack is not 75 ohms impedance. Period. End of discussion.
Even if, by some miracle, the RCA plug itself could be made to be a 'true' 75 ohm impedance, which I am not convinced that it can be (nor are quite a few knowledgeable RF folks and engineers), then it would still be a moot point since the RCA female jack is not a 75 ohms Z.
Yes, the RCA plug on the right will be slightly worse than the one on the left, as it does have a "constriction" in the overall diameter of the barrel to center pin, as shown. This is not necessarily a show stopper, or a huge problem. After all, as we have seen earlier, the plug shown as being of a 75 ohm impedance, has an impedance discontinuity due tothe differing diameter of the inner barrel where it is cut out for access to the center pin.
So these RCA plug related impedance discontinuities are more a matter of dgree, rather than any sort of absolute.
[ That being the case, only a few component video cables actually have true 75-ohm RCA connectors since very few exist. ]
In point of fact, no real 75 ohm impedance RCA plugs exist. Much has been made of a certain brand of plugs that do everything they can to promote this myth, but if the claims and wording of this brand of plug is examined closely, one will find that words and phraseing like "75 ohm coaxial cable compatible", or "impedance-matched" or they make reference to a VSWR measurement, but they really never come out and SAY that the plugs are actually endowed with a 75 ohm impedance, nor do they mention if the plugs were measured for VSWR when actually plugged into a female RCA jack!
SEC 3.7 Jackets and Sheaths
This section is very confused, as so much is misstated for the subject line.
[ The disadvantage of PVC (as a jacket material) is its overall stiffness and lack of flexibility. ]
That's my parenthetical insert.
PVC, with the addition of the proper type and amount of plasticizers, is one of the THE most flexible jacket materials, and is often the only choice if cable flexibility is needed.
[ Polyurethane is restricted to use in jackets only, due to its poor dielectric properties. ]
While I am not found of PU's dielectric properties, and do not recommend it be used as an insulator, especially for coaxial cables, it IS used as a coating on lots of magnet wire, and so, IS used as an insulator, contrary to what this article says. As a matter of fact, I am not ware of too many cable jackets that use PU either, when PVC is cheaper.
[ Polyethylene is the compound most widely used in coaxial and low capacitance cables due to its fine electrical properties. ]
This is true from an center insulator (dielectric) standpoint, but has little relevance for use as a jacket material. In |
| re: Critique of Video Cable Tech Article, Part 7 | Jon
Jan 2, 2003 10:32 PM | | Part 7
[ Polyethylene is the compound most widely used in coaxial and low capacitance cables due to its fine electrical properties. ]
This is true from an center insulator (dielectric) standpoint, but has little relevance for use as a jacket material. In point of fact, PE is seldom used as a jacket material, due to cost and stiffness.
[ Nylon has a very low coefficient of friction, making it a good choice for use in high flex applications. ]
While this is true for certain types of wiring, such as THHN type wires, run inside conduits for AC power, nylon is hardly ever used as a jacket material for coaxial cables, as it is too stiff, and would tend to encourage kinking of the inner dielectric, compromising the impedance of the cable.
This whole section looks like it was lifted right out of some cable manufacturer's web site, only, it was in the section on INSULATORS, not jackets. Sheesh!
SEC 4.0
[ Based on the lengthy discussions in each section, marketing schemes such as the misuse of the term skin effect and the entirely made up term known as strand jumping were found to have little to no effect on cable performance. ]
This is not exactly the case, as I have already pointed out, and while SOME equations and "math" were presented, they do not definitively show that what he states is some sort of inherent mathematical truth.
Aside from contradicting himself on skin efect, and whether or not it needs to be addressed (is stranded wires and silver plated NEEDED, or not?), he does not address the other aspects of skin effect issues.
This includes the very reasons that strand jumping may occur, which is going to be skin effect driven.
Given that only some of the issues were discussed, how is it that skin effect and strand jumping "were found to have little to no effect on cable performance" ? Found by whom?
[ Dont be fooled by to good to be true marketing claims that are abundant when considering the multitude of cables on the market. ]
Including claims about true 75 ohm RCA plugs, stranded wires being significantly superior to solid wires, and silver plating being needed for video cables?
Summary and Comment
The general tone of the article is one of an adversarial one towards cable vendors, as if they were out to try and "trick you" or cheat you with techno-bull, but the article itself has obviously accepted without reservation certain specific vendor's 'techno-bull', and proposes this as the gospel truth.
You are told that solid wires are used because they are cheap, not really the case, and in fact, it may be that a solid wire is actually superior for video/RF use.
You are told that some video cable vendors are selling you strand jumping, when I do not know of any vendor doing this.
You are told that some vendors provide "true 75 ohm" RCA plugs, in contrast to other vendors, when in fact, it is highly unlikely that there are ANY "true 75 ohm" RCA plugs", and even if there were, it is a moot point due to absolutely NO "true 75 ohm" RCA JACKS!
You are told that silver plating is desirable, even though it will not matter. (Silver plating costs money)
You are told to look at solder joints, without the whole story of what to look for.
Frankly, I think that such an article, pretending to be the last word on the technical aspects of video cables, does the video enthusiast a disservice, because some poor fool is going to believe the contents, and run out and buy a silver plated, stranded center wire, RG-11 sized cable with special non-impedance consistent RCA plugs.
The ironic part is, this highly sophisticated super duper video cable may or may not perform any better than other video cables, how can anyone tell for sure from all the 'technical' information in this article?
Jon Risch |
| Jon | jneutron
Jan 3, 2003 12:40 PM | | I thought I was bad with the 5 parter :-)
In reviewing a cable vendor's site, I e-mailed the author, and am discussing the technical errors. He was very receptive to comments. I assume that he will make the decision to update his site based on a competetive advantage. If enough vendors actually correct their errors, perhaps the advantage would be to do so.
Have you tried this approach?
Is not the impedance of a coax defined by a mathematical relationship between inductance per foot and capacitance per foot? And as such, can't the dielectric within the RCA plug and jack be tailored to provide either 50 or 75 ohms?
The only real issue would be the cross section dimensional changes from one geometry to another. Whether or not this type of engineering has been done for any RCA's..I don't know. Perhaps the discontinuity size is so small compared to wavelength that it is considered a non issue with little performance tradeoff.
Cheers, John |
| John | Jon
Jan 3, 2003 10:08 PM | | If you mean that I should contact audioholics, or as Pat D suggested, post there, I am not sure that it would do any good.
My experiences with audioholics have not been very good.
I posted there regarding cablkes some time ago, and was promptly attacked by several of the audioholics staff.
I later realized that the content of my original post had been edited (without any notice or explanation), and that the repies to my post had also been edited (the only notice was a small note at the bottom of the reply window), so as to make me look like a fool, and to correct the errors in the replies.
Not exactly what I would call an even playing field. The ironic thing is that I get accussed of playing God, yet these guys are certainly taking liberties with the facts and with other people.
After this fiasco, I refused to post there any more, as it could only be used against me at will, with a flick of the mouse.
We shall see if any of the errors I point out are quietly "fixed" without any notice or history, or are just ignored.
At least I can set the record straight for a few folks
Jon Risch. |
| 75 ohm RCA | jneutron
Jan 4, 2003 7:09 AM | | Do you know of any efforts to make 75 ohm RCA jacks and plugs? It's possible, but was wondering if anybody bothered.
TTFN, John |
| 75 ohm RCA | Jon
Jan 4, 2003 10:20 AM | | Actually, I do not think it is possible, as the existing dimensions are wrong. Due to the diameter of the center pin, the spacing between the center pin and outer shell is too small to get "up" to 75 ohms. If I remember correctly, these raw diameters end up maxing out at approx. 63 ohms or so (with air as the dielectric). Use of a dielectric material with a constant greater than one results in lower impedances, not higher. Since the best practical insulation we have is teflon, with a dielectric constant of about 2, no way Hose'.
Strictly speaking, the diameter of the RCA plug inner barrel that is away from the solid dielectric holding the center pin in place would have to change size in order to maintain a constant impedance, the air and the plastic will result in different impedances for that short length.
Making an RCA plug (and jack) 75 ohms would require a dielectric with a negative permitivity, and while work on meta-materials has progressed to the point where they do have a meta-material with negative permitivity AND negative permiability, this only operates over a small band of ver short wavelength EM frequencies as of now, and is not likely to be practical for audio wavelengths, due to the sheer size this would require of the meta-material's matrix, and the wide frequency range of the audio band.
Jon Risch |
| 75 ohm RCA | jneutron
Jan 4, 2003 10:44 AM | | I'd have to review the math to be sure, but your analysis appears reasonable. And, negative mu materials, not possible agreed.
Thanks, John |
| 75 ohm RCA:it's possible, any manufactureres interested? | jneutron
Jan 6, 2003 6:41 AM | | Been thinking about it Jon.
I believe it is possible to make a male/female RCA set which is capable of 75 ohm impedance. Same form factor, so mechanical compatibility is not an issue. And it doesn't require negative permittivity materials.
I do not know if anyone out there is interested in producing it, nor if the difference to video or digital audio is worth it.
If anybody is interested, please, contact me.
Cheers, John |
| 75 ohm RCA:it's possible, any manufactureres interested? | FLZapped
Jan 7, 2003 9:09 AM | | John,
Well, the rough formula for a coaxial cable is:
Zo= 138/(e^(1/2))*log(D/d))
Where:
* log = logarithm of 10
* d = diameter of center conductor
* D = inner diameter of cable shield
* e = dielectric constant (= 1 for air)
The center pin diameter of an RCA connector is about 1/8 inch. (0.125)
If you look down in the barrel of a male connector, there is a ring that appears to be just shy of 0.25 inches.
This sets the D/d=2 and log(2) = 0.3
So to get to the impedance we want, we would need
a dielectric constant for the insulator of about 37.6.
But that's only half the problem. The center pin extends out beyond the outer shield area and the mating female connectors are made with this exposed instead of covered the way it would need to be in order NOT to have an impedance bump. Of course, unless the calbe attachment is designed to maintain constant impedance it too needs to be changed as current RCA connectors require a split of the cable conductors into something other than coaxial.
-Bruce |
| Hi Bruce Hmmmmm..... | jneutron
Jan 7, 2003 10:31 AM | | Didn't Jon say it would require a negative dielectric constant, as the geometry in air dictated,um, what was it, 61 ohms?? Where is the error here? At least this is a black and white problem. I like these.
Pin's not a problem..requirement is the use of the old cables in the new jacks, and new cables in the old ones. And still make 75 ohms.
I stand by my assertion. I think either direction can be accounted for.
TTFN, John |
| Hi Bruce Hmmmmm..... | FLZapped
Jan 7, 2003 7:10 PM | | b At least this is a black and white problem.
Plus or minus 3dB, anyway :~)
-Bruce |
| Aww Man?? What kinda response is that???? | jneutron
Jan 7, 2003 7:33 PM | | C'mon bruce...what's the story??? 75 ohm RCA dude!!!
For your scenario, that of high dielectric constant...
The impedance of the overall connection can be modulated by the amount of meat in the female.
Use a smaller insulation cylinder in the jack, and more metal, and you can live with common dielectrics. The design must extend the metal all the way into the male..But that already happens. On the chassis side..Just extend it, give a coax connect.
For Risch's, needing negative die's...Reduce the inner prong diameter...Who says the pin has to be all metal...Use a smaller wire diameter, run it around the non conductive pin..Do the same on the female, opposite helical pitch to guarantee contact..And they both mate with existing RCA combo's.
(sorry, got impatient and was chompin at the bit..)
Damn, I love this stuff!!!!
Cheers, John |
| Wait until you see this one! | FLZapped
Jan 8, 2003 9:51 AM | | b For your scenario, that of high dielectric constant...
Please use the formula and double check my math. I could have screwed something up....
b The impedance of the overall connection can be modulated by the amount of meat in the female.
Yup: (D/d)
b Use a smaller wire diameter, run it around the non conductive pin..
WHOO HOO! A helix antenna! Now, it is axial radiation or radial radiation mode? Okay, so it's in the terrahertz range....
You realize that this looks like a tuned stub and will resonate at some frequency.
b Do the same on the female, opposite helical pitch to guarantee contact..And they both mate with existing RCA combo's.
Okay, but I believe these will act as a solid metal connector. (Not immediately sure if the dielectric will have a loading affect or not.)
b (sorry, got impatient and was chompin at the bit..)
Keeping your dentist busy I see.....
b Damn, I love this stuff!!!!
I hope this doesn't exault you to the heights of ego masturbation there John.....
-Bruce |
| HOOO BOY!! Wheres my cheeze wiz? | jneutron
Jan 8, 2003 10:03 AM | | Ego?? No, lost that in the separation agreement.
""tuned stub and will resonate at some frequency""
definitely will...gig or tera range, I would assume.
Could drop the helix, go with offset straight ribbon on both male and female, but that will require keying of the connector, losing old to new interchangeability. Could have keying outside the shell to make that work, if the key didn't inhibit using old RCA's.
TTFN, John |
| As it seems no manufacturer is interested,,,, | jneutron
Jan 7, 2003 7:35 PM | | It would seem the solution is in the public domain now...
Course, the techniques were developed during WW two, by the british postal service...
Ahh, I just love history.
Cheers, John |
| Somewhere, sometime, there is going to be.. | jneutron
Jan 7, 2003 7:54 PM | | some very interesting patent claim lawsuits regarding innovation on websites..It's gonna happen, I tell you.
Somebody's gonna put a novel idea on the web, like 75 ohm RCA's, and them somebody else is gonna patent it.
Public domain questions are going to be interesting in the future, as more web based collaborations occur.
TTFN, John
PS... Where you at, Phil??? |
| Now we're getting someplace. | pctower
Jan 8, 2003 9:06 AM | | More work for the lawyers. |
| I knew we could count on you Phil!! (nt) | FLZapped
Jan 8, 2003 9:40 AM | | |
| No 75 Ohm RCA plugs/jacks | Jon
Jan 14, 2003 11:06 AM | | What is the closest to a 75 ohm impedance that an RCA plug/jack can come?
Well, if we take the straight center pin size, and the straight outer shell sizes, and do the calculations, and assume a teflon dielectric with a constant of 2.1, then it is approx. 40.3 ohms.
EQUATIONS:
Cable (or plug) Z = (138 / SQUARE ROOT OF e) * log (D/d)
d = diameter of center cond.
D = inner diameter of outer shield
e = dielectric constant
log = logrithm of 10
(only good for an infinitely long cable)
Dimensions of an RCA plug:
d=0.125"
D=0.330"
A smaller outer shell would only make this lower in impedance.
If we used a foamed teflon as an insulator, or some sort of hollowed out insulator, that had a dielectric constant of 1.5, then this would rise to approx. 47.5 ohms Z.
An insulator with a high dielectric constant would only make things lower in Z as well.
Some have proposed a spiral center pin, to effectively reduce the diameter of the center conductor. However, even if this were feasible, it would not change what is going on with the female RCA jack. In point of fact, such an arrangement would not work at the frequencies of interest, and would behave as if it were a solid center conductor of the same diameter as the original center pin.
Most such tricks either fail at the frequencies of interest, or cause their own problems.
So it should be clear at this point, that it is not possible for an RCA plug to acheive a true 75 ohms impedance.
Jon Risch |
| Hi Jon | jneutron
Jan 14, 2003 11:57 AM | | Thanks for the analysis, Jon. The .33 is the diff from Bruce, he estimated .25.
Spiral was proposed to meet existing equipment form factor, and to allow non keying operation. And nothing prevents the female from spiralling in the other direction. If the two spirals contact in more than one point, the impedance is certainly of concern. But, arranging the spirals to only cover 180 degrees on each part can guarantee only one point contact.
And, if instead of spiralling wires, use a flat ribbon on each, with correct geometry for the dielectric type of course, and now you have to key the new type to guarantee alignment of the ribbon contact, with the keying mechanism not affecting the compatability in any direction. Compatable keys are easy to design to allow old and new to be completely interchangeable.
It is definitely possible.
Cool..I like the technical conversations.
Cheers and thanks, John |
| Your experiences there sound strangely like MM's at AA. | markw
Jan 6, 2003 7:06 AM | | The only difference is that at Audioholics you were on the receiving end. Did they ban you also? |
| Posting on Audioholics forum - Jon LIES! | stevied4him
Jan 6, 2003 7:50 AM | | To everyone,
Jon's statement above is a pure, genuine 100% outright lie. Audioholics NEVER changed or edited anything Jon wrote in the forum section.
Why would anyone believe a man that deliberately lies for his own self-promotion?
Secondly, what Jon calls an attack on our forum was nothing more then a debate with our technical staff regarding his flawed logic. Is it anything different then what Jon and his followers do here or in his Asylum?
As for "fixing" the article quietly, that will NOT happen as there is nothing to fix. Yes there will be some grammatical updates and clarifications. In fact, Audioholics is happy to post a before and after of the minor changes/updates as we have nothing to hide.
Bottom line, when this discussion and bashing you started has gone to the bottom of the forum, the article will still be there and will continue to dispel the myths and fallacies you so gallantly promote on this and other sites. |
| Nope! | Jon
Jan 10, 2003 10:01 AM | | Initially, out of the posts that were made, some were edited, including mine, and some appear to be deleted. This was over that Jim Jones/Jimmy Swaggert thing.
I know my post was edited, because I had a copy of what I had originally posted.
[ As for "fixing" the article quietly, that will NOT happen as there is nothing to fix. Yes there will be some grammatical updates and clarifications. ]
If you truly believe that there is nothing to fix, then you are operating in a dream land of techno-BS, and are no better than the folks you claim are pushing techno-BS. Besides, if there is nothing to fix, then why would there be any need to provide grammatical updates and clarifications ? Either it was correctly worded in the first place, or it had some confusing text content (one of my contentions).
So I am wrong about the article needing fixing, but you are going to fix it anyway? Yeah. Uh Huh.
[ In fact, Audioholics is happy to post a before and after of the minor changes/updates as we have nothing to hide. ]
Maybe you will, and maybe you won't. How would anyone know unless they had made a copy of the orignal article?
[ Bottom line, when this discussion and bashing you started has gone to the bottom of the forum, the article will still be there and will continue to dispel the myths and fallacies you so gallantly promote on this and other sites. ]
Like some other naysayers, you make claims about me and my posts, but provide no techincal back-up or citations or references. That is because there is nothing to back up what you are saying.
As for your faulty article, even after it has been "grammatically updated and clarified", it might still be a joke in terms of technical content.
Still going to recommend silver plating, even though some of the content appears to counter-indicate it's use? Still BSing about stranded wires being better (and more expensive for the manufacturer)? Still claiming that RG-11 is necessary for anything over a 2M run of cables? Sheesh!
Jon Risch |
| Jim Jones? I think you mean Jim Baker, don't you? | markw
Jan 11, 2003 6:27 AM | | You mean you STILL don't know the difference even after it was pointed out to you?
When someone compared you to Jim Baker, the charasmatic televangelest you "overreacted" and started jumping up and down saying how dare he compare you with a person who led others to their deaths by misleading them.
Of course, you were mistakenly thinking about Jim JONES, of Ghana fame. This was glaringly obvious to almost everyone else who was following htat thread even before it was pointed out to you.
When this mistake on your part was pointed out, you simply did not respond.
Odds are that the impression that you wanted to give wasthat you were so offended by your original "misinterpertation" that you didn't bother to participate further. Of course, there are those that saw it as simply a convenient way to wiggle out of a loosing confrontation.
Guess we'll never know, will we? |
| Jim Jones? I think you mean Jim Baker, don't you? | Jon
Jan 12, 2003 9:59 PM | | That was a part of the editing and deleted posts I was speaking of.
I can no longer access any of those specific posts at Audioholics, they appear to have been deleted.
In point of fact, one of my posts there was edited to make it look much worse than what I had originally posted, and one of the original posts from audioholics staff was edited to make me look bad.
Yes, I know the difference between Jim Jones and Jim Baker.
Neither one is exactly flattering, but I did get very angry when I thought I was being compared to a cult leader that caused so many people to lose their lives. There would be no excuse for that kind of villification, under any kind of civilized net behavior.
As for that loosing confrontation bit, I would say that the articles so far on cables at Audioholics have been pretty sophomoric and not at all the definitive kinds of articles they seem to think they are producing.
Do YOU think that Steve should clarify whether or not he is recommending silver plated and stranded video cables, or if he is right about a "true 75 ohm RCA plug"? Should any video cable over 2M be required to be RG-11, or is RG-6 or GR-59 style coax OK?
I think his article leaves a lot to be desired, and is NOT the neutral, math based think piece that was promised, or that it was the Complete Guide to anything, much less the truth about video cables!!!
Jon Risch |
| A true 75 ohm RCA can be made. | jneutron
Jan 13, 2003 8:45 AM | | All the rest of the conversation?..Not mine..
Cheers, John |
| How Sad a Man is Jon Risch | Suppers_Ready
Jan 11, 2003 9:05 PM | | Who saves forum messages? Now I have heard everything. Lets see it Jon. Post it. For if you really do have this message saved then you really do need to get a life as so many people on here have pointed out in the past.
You do remind me of a cult leader. You preach your fallacies on cable theory at your psuedo front website and then gather your followers on Audioasylum. |
| How Sad a Man is Jon Risch | Jon
Jan 12, 2003 9:46 PM | | The time I have to spend actually connected to the internet is limited, as is my total free time to spend on such things.
Despite speed reading, and speed typing of replies, I often have to copy a given post, and later type a reply on a laptop or other computer off-line. I save them as simple text files, compose a reply, and then copy and paste the typed reply into a message board reply once I am back on-line.
Hence, I would have a copy of a great many posted replies, especially the long ones!
That is how I have all the copies of many of my commonly asked Q's posts, some of which are listed in my Annotated Cable Bibliography, at:
http://www.geocities.com/jonrisch/c4.htm
So it is not such a mystery as to why orhow I would have a copy of any given post, but as noted, especially the longer replies. It is not uncommon for a disconnection, system or browser crash to loss a reply, and so, I do not risk it with anything past a few quick sentences. Even this reply has been temporarily copied to a temp file, in case the AR board "burps", and I lose all the typing! Then, all I have to do, is re-connect/re-start and use the History file to go back to the post, and copy and paste.
[ You preach your fallacies on cable theory at your psuedo front website and then gather your followers on Audioasylum. ]
You are quite mistaken. First, I would like to see specific instances where my cable theories are fallacious.
Of course, you will provide impeccable and completely valid and relevant citations and references to prove your statements?
Second, Audio Asylum is a public moderated message board, which has many sections. I post at several regularly. However, it would be the height of paranoia to think that I had a cult following at any one of the various message boards at AA.
One could as easily say that mtry has a naysayer cult following here. Are you a member of mtry's cult?
Jon Risch |
| Theories | jneutron
Jan 13, 2003 9:04 AM | | ""First, I would like to see specific instances where my cable theories are fallacious.""
I personally prefer the term "unsubstantiated"
Your skin theory vs phase smearing I will address here. There are others, but the argument remains the same.
You have no (none, nada) credible, scientifically backed evidence that skinning causes phase smearing. None..Trust me, I know. You cannot test for it, you cannot use equations to define it, you cannot provide even one prediction as a result of your theory. You cannot find even one CREDIBLE e/m physicist to concur. And, from what I'm finding historically, you are not the first to push this. So far, every link to "evidence and tests" that it exists have turned out to be ridiculously contrived, horribly tested, completely without scientific merit. Also, I find that some of the debunkers actually don't debunk either.
That I am trying to model a physical process which can mathematically prove the existance of such...Does not lend credibility to it. It's still an unscientific, unproven theory. Merely conjecture. If I pushed it as the answer right now, I'd be pushing fallacy. I will push it when I can repeatably provide test evidence. If I find none, I will report same.
I cannot say if it exists or not. If I find it, I can state absolutely that it exists. If I do not, I cannot state it doesn't exist, just report what was unable to find it. Although some would prefer absolute no, that doesn't exist within the scientific process framework.
Cheers, John |
| And by the way... | jneutron
Jan 21, 2003 11:09 AM | | ""You have no (none, nada) credible, scientifically backed evidence that skinning causes phase smearing. None..Trust me, I know. You cannot test for it, you cannot use equations to define it, you cannot provide even one prediction as a result of your theory. You cannot find even one CREDIBLE e/m physicist to concur.""
Lest anyone think otherwise, I ALSO cannot test for it, I cannot use equations to define it, I cannot provide one proven prediction, nor can I find a physicist to concur.
Tis not a personal affront, but more a testimony of SOTA.
I'll soon have my test setup up and running, to try my hypo..
TTFN, John |
| Jon - misleading the public again. | stevied4him
Jan 12, 2003 6:11 AM | | The silver plating mentioned in the article that you keep hopping on, was discussed as a method of minimizing oxidation (which it does). You and your twisted way keep taking one phrase out of content and warpping it into your own view so you can criticize it, which is basically all you know how to do.
Jon, are you still going to promote "strand jumping" and "cryo-genic freezing."
Man, I hope so because we have many new articles coming out on audioholics that will dispell this nonsense too.
Keep misinforming the public Jon, you do it better then anyone I know. |
| Now we have something concrete to look at. | Jon
Jan 12, 2003 9:13 PM | | In section 2.3 , you stated: " When a copper conductor is plated with pure silver with a thickness of 50 microns, 92% of the current density will be in the silver. Since silver has a 10% gain in conductance compared to copper, a copper wire plated with silver will have less signal loss especially at longer lengths, thus minimizing skin effect."
AND
"In this section, we have shown that at the maximum range of component video signals (10MHz), skin effects only cause a minimal loss of 0.047 db of the total video signal. In addition, this loss can be reduced by using stranded wire for the conductor to increase the overall area, and by using at least 50-microns of silver-plating on the conductor strands to decrease the resistance in the surface where 92%+ of the signal is conducted. By using stranded conductor and silver plating, skin effects on component video cables can be considered insignificant."
These are both skin effect related issues, and come first in the article.
Now, in section 3.1, you do discuss silver plating, and how it might help reduce oxidation of the copper wire.
However, you do not stress that this is the reason to seek out silver plated wires.
You also make an isolated valid point about the soldering, and how heating a wire with high oxygen content might make it brittle.
However, if we look at this carefully, it becomes clear that a silver plating would not realy affect this, as it would only protect against SURFACE oxidation, and NOT be relevant to how much oxygen was inside the wire.
It is a trivial thing to have silver plated ETP copper, and therefore, it would have the same potential problems with brittleness, despite the silver plating. Unless the wire was free from oxygen on the INSIDE, where the silver plating does not matter, it will still have the potential problem of becoming brittle.
Ironically, silver plating WOULD help with strand jumping issues, however, you have also stated, completely irrelvant to any claims by video cable manufacturer's, that strand jumping is not significant. SO it is still not clear WHY you would recommend silver plating.
RE cryo treatment of audiom cables, I have not posted very much on the subject, not having made any controled comparisons between cables that have been cryo treated and not.
However, that does not keep me from researching it, and finding out that many items are affected when cryo treated, including brass musical instruments, such as trumpets, trombones, etc., and that knives, camshafts, rifle barrels, etc, al respond to cryo treatment. These items ALL are altered when they are treated, on a molecular level, a sort of annealing process. You claimed in your article, that "Once the cable is warmed, it is the same cable it was before being frozen. "
Obviously, this is not true on a molecular level for the cable conductors.
You were wrong.
Of course, I never said that cryo treatment resulted in any sort of sonic benefit, as I do not have nay data or personal experience with that aspect. It is possible that it may, or not. But your statement was WRONG.
Anyway, I am not aware of any of the mainstream video cable manufacturer's who make claims about cryo treating their video cables. This seems to be another one of those back-sided, "we aren't going to discus or respond" cheap shots at audio cable issues, that are presented with out any citations or back-up.
No where in your list of citations are there any sources that provide back up for your claims of:
no effects due to cryo treatment
or
no such thing as strand jumping
or
skin effect is a relevant issue for video cables, and they need silver plating and stranded wires.
In point of fact, the whole reasonI wrote my response to your article, is that I feel it is"misinforming the public".
It is indeed ironic that those at Audioholics pretending to provide the scientiifc truth, are themselves selling BS and psuedo science.
Jon Risch |
| Cold cinder blocks | jneutron
Jan 13, 2003 10:00 AM | | ""....affected when cryo treated, including brass....etc., and that knives, camshafts, rifle barrels, etc, al respond to cryo treatment. These items ALL are altered when they are treated, on a molecular level, a sort of annealing process.""
That fact does not necessarily carry over to all materials. For steel, the amount of martensite present at room temp depends on quench rate, and alloy composition. However, martensite has a lower lattice energy, it will continue to be made at room temp, over time, until there is no more energy gain in the conversion to body centered tetragonal structure. When subjected to cold, as in cryo treatment, the lattice will speed up the conversion, until the martensite finish temperature is reached, where all the austenite is transformed. It it that type of transformation that alters the macro level properties.
However, most metals, silver and copper included, do not undergo this type of irreversible lattice change through cryo treatment. Alloys, yes..It is not possible to carry one technology instance over to another without first establishing lattice changes. Many, many materials do not alter their microstructure through cryo temperatures, all the way down to superfluid helium (1.8 degrees above absolute zero).
I've seen no viable research showing silver and copper do such.
Cheers, John |
| John, what's your professional opinion? | RADAR O_Riley
Jan 16, 2003 10:36 PM | | John, how would you handle this? Are we seeing peer review in action, or are these two guys just having a wee contest ("wee" being what you and I don't do into the wind). This seems very unprofessional to me. No one party is guilty of unprofessional behavior; All parties are equally guilty. I could be wrong about this, but a public forum just doesn't seem like an appropriate place for a hostile peer review. As one who has his work regularly exposed to formal review, what do you think of all this?
Is this really the way professional engineers behave when they review each others work?
RADAR O' |
| This... | jneutron
Jan 17, 2003 8:36 AM | | ""As one who has his work regularly exposed to formal review, what do you think of all this?""
I like it better that the WWF. TV is boring in comparison.
""Is this really the way professional engineers behave when they review each others work?""
Only behind closed doors..
Seriously, in this new age of forums, internet, online chatting, all us oldtimers have to adjust to the new presentation. We all take for granted the ability to face to face, as a huge amount of information is conveyed by body language, expressions, inflections, tools which we've grown up with. I find it's far too easy to say something that's taken the wrong way, and far too easy to sit back and develop a reaction one knows will be viewed by all. My thread with RobotCzar up above is a good example. Two intelligent people, basically duking it out in public. He's correct, and I'm correct, but in a public venue, it get's out of control.
Civility in this new forum has to be re-learned.
I'm jealous of my children..They are in this from the start, we're the ones who have to learn.
Cheers, John |
| ... not a fighter. | RADAR O_Riley
Jan 18, 2003 12:33 AM | | So if the kids are into drive-by shootings, are we supposed to learn to appreciate such things?
I've both seen, and been involved in, some heated internal reviews, but I've only seen the kind of stuff I see here once during a customer review. An older and more experienced engineer tried to play the same kind of game with me that I see people playing here. He challenged a part of the design I was presenting. I answered his question, and tried to move on. He ignored my answer, and ask the same question again, this time more aggressively. I asked him a couple of questions to make sure I had understood his query, then I gave him a much more detailed answer. Again he ignored my answer, and he started to get into my face (and yes, the guy did have a chip on his shoulder, there was no problem with the design). At that point I was literally speechless. I had no idea how to deal with the situation, I still don't, and I don't care to get into situations where I'd have to learn. I didn't learn then because the WRAL Lab Manager stood up, leaned over the table, and got into the mans face, almost nose to nose. It's the only time in two decades that I ever saw Tom Barrie loose his temper, and at that moment I'm almost certain he was within an inch of getting into a fist fight.
I'm a lover, not a fighter. My temper encourages me to avoid arguments. Life is easier for all involved if I simply walk away from irrational discussions. I'll pass on the drive-by shootings too. :-)
As for the kids, mine sees a computer as an appliance, and uses it as easily as I use a toaster. Still, if her behavior is unacceptable, I don't really think that I'm the one who has something to learn. That could just be because I'm an old-fart, and stuck in my ways, but if so, so be it.
RADAR O' |
| Cold cinder blocks | jneutron
Jan 27, 2003 6:49 PM | | Damn.. The worst part is...Nobody's here to read my response...Tis lonely on the second page..
Oh well..
The Forgotten... |
| Nope, you're wrong and you're still a lier | stevied4him
Jan 10, 2003 5:58 PM | | |
| Jon | Monstrous Mike
Jan 4, 2003 10:40 AM | | I also gave the thumbs down to that article and the author responded to me at this site so I would say he is reading all this and perhaps will take it away and fix his errors. |
| Out O'curiosity... | Resident Loser
Jan 3, 2003 7:21 AM | | ...have you posted any or all of this ponderous tome at the site you mentioned...I mean, while AR can most likely use all the traffic such rod work can generate, isn't it sorta like complaining about the bad service or poor food to your table mates and not confronting the waiter/restaurant staff about it?
jimHJJ(...if, somewhere in this rival for "War And Peace", you have done such and stated so, my apologies...BTW, let me know when Cliffs Notes or Classic Comic Books publishes the synopsis...Oh yeah, Happy New Year...)) |
| Out O'curiosity... | Pat D
Jan 3, 2003 9:53 AM | | Well, when I looked a little while ago, Jon had not taken the opportunity to reply on the Audioholics site. |
| "re: Critique of Video Cable Tech Article, Part 99999999999" Jon | skeptic
Jan 4, 2003 5:33 AM | | zygospore
\Zyg"o*spore\, n. [Gr. ? a yoke + E. spore.] (Bot.) (a) Same as Zygosperm. (b) A spore formed by the union of several zo["o]spores; -- called also zygozo[\"o]spore.
I think that's the last word....in the dictionary!
Heheheheheheheheheheheheheheheheheheheheheheheheh |
| Jon, please describe your opinion of a "good enough" cable | treeman
Jan 4, 2003 11:58 AM | | The generaliztion by many is that video signals are easier to transmit than audio.
Therefore, inexpensive video cables deliver a picture as good as the expensive ones (within reason).
For the lay person, describe your "good enough" cable for a "average setup" whatever that might be.
Is silver coating needed? Why or when? It seems to be the first upgrade in "better" cables.
Brands? Is readily available Acoustic Research (3 quality levels) or Rat Shack good enough?
What's your bottom line? Thank you - from a non-audiophile looking for value and performance. |
| Jon, please describe your opinion of a "good enough" cable | mtrycrafts
Jan 4, 2003 3:20 PM | | Only his design comes close:)
b The generaliztion by many is that video signals are easier to transmit than audio.
That may be the generalization but it doesn't mean that it is so. Same as with Sylvia Brown or John Edwards of Crossing Over fame :)
b Is silver coating needed?
Nope, not in audio or the video used in home applications.
b It seems to be the first upgrade in "better" cables
Yep, doesn't mean that it is needed.
b Brands? Is readily available Acoustic Research (3 quality levels) or Rat Shack good enough?
Plenty good. Some agonize over things that are of the least important. |
| Jon, please describe your opinion of a "good enough" cable | skeptic
Jan 5, 2003 6:19 AM | | The generaliztion by many is that video signals are easier to transmit than audio.
Wrong and not even close. An audio signal with only a 20khz bandwidth is duck soup compared to a video signal. At the composite NTSC video level, the bandwidth requriement is over 6 Mhz or 300+ times as great. At the RF level, it's closer to 1 GHz for the higher frequency VHF channels. Even the audio subcarrier and its sidebands is far less critical for television transmission than just the colorburst subcarrier. When tv sets required alignment, that was one of the most important and critical things to align for, not the audio. And when you get passed just moving the signal from point a to b along a wire and get to broadcast transmission of video vs audio (television vs radio) the difficulty of getting acceptable results is compounded many fold for video. There never would have been a cable industry if not for television. Cable radio? |
| Jon, please describe your opinion of a "good enough" cable | FLZapped
Jan 5, 2003 4:56 AM | | i Is silver coating needed? Why or when? It seems to be the first upgrade in "better" cables.
Not in this application. If you were talking high power transmission, yes.
i Brands? Is readily available Acoustic Research (3 quality levels) or Rat Shack good enough?
Probably, but the Rat Shack has been cranking prices up of late. You can et what you need in Home Depot(Mine carries RCA brand) or Best Buy or....
The same DOES hold true at audio too, just the BS has had more time to propagate, percolate, and permeate.
-Bruce |
| Coathangers? | Jon
Jan 5, 2003 10:44 AM | | For some, coathangers might be good enough!
However, I am going to assume you asked a serious question, and so, I will provide a serious answer.
Theory says that the foamed PE combo braid coaxial cables, such as Belden 1694A, should be good enough, since they would be able to provide all the TV signal parameters with more than enough margin to pass a visibly 'perfect' TV signal.
However, despite this, some folks have been reporting that the teflon version of this cable, 1695A, provides a better picture: sharper, better color saturation, finer detail, etc. I personally have not seen this beyond any shadow of a doubt, on my system.
Sysem application details would tend to be a sensible way of lookign at it, just as you would not use the most expensive cables for a mid-fi audio syustem, neither should the finest cables be used for a 10 year old 19" TV.
Start talking about a projection TV, a big 36" direct view TV, and maybe now one should go for the best performance without spending a small fortune.
In terms of retail cables, I have found the Maganvox gold-plated cables available at Wal-Mart and K-mart to perform quite well, and visibly better than many cheap or OEM cables on my 36" direct view Toshiba. Most of the difference lies in how good the color purity is and lack of color smear in the picture. I have tried the 1694A, and the 1695A, and found no visible improvement over the Magnavox cables TO ME, ON MY SYSTEM.
I once worked for a man who could see the presence or absence of the 8th bit on a digital video DAC, while most folks would be hard pressed to see the 6th bit toggled on or dead. (FWIW, I could just barely see the 7th bit on studio broadcast monitors, under ideal conditions.)
The TV set is theoretically limited to a maximum visual dynamic range of about 40 dB or so, the TV signal has a dynamic range from full white to full black of only about 22 dB, and so, according to theory, one should not be able to tell anything beyond the 7th bit (approx. -42 dB down from full picture brightness), yet my fellow engineer could see ("blind"testing, nearly 100% accuracy) the 8th bit accuracy being present, which is approx. -48 dB down.
So what is good enough for a video cable? How good is your TV set, how discerning is your vision, how used to seeing television artifacts are you and how much do they bother you?
If you were referring to what is good enough for audio interconnects, then once again, what system are we talking about, how experienced are you at hearing subtle abberations in the signal, and what bothers you the most in terms of deviations from a perfect signal.
My personal experience with RS cables for audio has not been that good, they do not seem to have enough performance for even mid-fi systems. The AR cables might be slightly better, I have not formally listened to them under controlled conditions, so I can not say for sure. Based strictly on their materials and construction, they might be equivalent to middle of the line brand name cables from Audioquest and Straightwire.
Many DIY designs can easily surpass these levels of performance, and even stock coaxial 89259 using some decent (Dayton) RCA plugs will sound better than mid-line aftermarket brand-name cables in most cases.
Jon Risch |
| Thank you much. Glad to see you admit to shopping Wally World | treeman
Jan 5, 2003 11:47 AM | | Thanks for the serious answer to my real question.
What is the supposed claim to fame for the silver coated copper? I'm just curious.
Now I have to go spray my new DVD player with Malathion - I just found out it has chroma bugs in it. |
| re: Critique of Video Cable Tech Article | Kid Charlemagne
Jan 5, 2003 9:08 PM | | Found this on Audioholics.
http://www.audioholics.com/cgi-bin/ikonboard/ikonboard.cgi?s=3e079ff62b91ffff;act=ST;f=4;t=225;r=1#top |
| Thanks for pointing out an excellent response , nt | mtrycrafts
Jan 5, 2003 11:39 PM | | nt |
| You mean the joke rebuttal? | Jon
Jan 12, 2003 9:30 PM | | Nope. Not even one point for tenacity.
See my reply, if it is still up at audioholics.
I have a copy if it goes away.
Jon Risch |
| re: Critique of Video Cable Tech Article | Kid Charlemagne
Jan 7, 2003 5:14 AM | | This is getting interesting. I'm reading more of this "debate" on AH and AS.
Seems to me that Audioholics quotes and takes excerpts from sources that include engineering textbooks, and multiple manufacturers who make coaxial cables, not component video cables. Straight to the source I suppose.
Jon continues to lists sources as 'HIS experiences' and other articles HE's written which appearantly all comes from people HE knows that MAY 'know about RF.' NO SOURCES THERE.
How is it that Jon can ask for proof from Audioholics when his only proof is himself?
Interesting.
Thanks Audioholics.
It seems that the old savings and loan is putting a damper on Mr. Potter's business. Why else is Mr. Potter so interested in trying to shut it down? Frankly, I'm glad the Internet is not just Rischville, I mean, Pottersville. |
| re: Critique of Video Cable Tech Article | Jon
Jan 12, 2003 9:27 PM | | None so blind as the double-blind?
In the list of citations in the audioholics article there are no sources that provide back up for the claims of:
no effects due to cryo treatment
or
no such thing as strand jumping
or
skin effect is a relevant issue for video cables, and they need silver plating and stranded wires.
I either have most of the referenced publications, or have access to them, and it is not in there.
Indeed, one of the examples of an error in the article that I specifically call out, is where he obviously takes information straight out of a cable manufacturer's catalog or web site, but it is originally about plastics used for DIELECTRICS, instead of the JACKETS he was supposed to be talking about in that section!
Pretty clear cut to anyone who really knows about plastics, or cables, or can go to a few cable manufacturer's web sites and verify what I said about this.
He could have cited the King James bible, but what RELEVANCE would it have had?
The citations and references have to have some relevance to be of any import.
In any case, most of what I posted about concerning the video cable Tech Article at Audiohoilics is NOT super esoteric or hard to verify information. However, one might HAVE to look up some things, just as someone would have to actually get a copy of the references cited in the audioholics article, and then read them cover to cover to find any possibly relevant content.
Interesting.
It does look like Kid C is just another dupe of the cable naysayers, this time, in the form of a "tech" article at audioholics.
Jon Risch |
| Don't be getting on my case, Jon! | Kid Charlemagne
Jan 13, 2003 6:36 AM | | I think I've kept quite for too long, but now that Jon chose to mock me, I have the following to say.
In Jon's words:
"They are real and have been documented for other cryo treatment applications, such as treatment of musical brass instruments, rifle barrels, knives, and various automotive engine parts. All of these changes are also very small, occur on the molecular level, and are known to provide a distinct benefit for the application.
Why not for audio cables too?
So where is YOUR proof that this is not so? Where are the citations showing that cryo has NO affect on audio cables?"
Why Jon? Because the following:
EVERY manufacturer of cables who claim cryo-freezing makes a difference also place in a disclaimer that the difference is not measurable, especially by resistance. In audio cables especially, resistance is the primary governing factor for the "performance" of a cable. Here's a bit of night time reading for you:
http://home.earthlink.net/~rogerr7/wire.htm
If you can not measure a difference in the cable's resistance before and after the cryo freezing, where is YOUR proof that it is beneficial. This is nothing more then a JOKE.
Cryogenic freezing is partially beneficial for the items you mention in your list because it is a form of stress relieving and those items slightly benefit mechanically (not electrically) from stress relief for many reasons NOT related to conducting electric current. Oddly enough, out of all your examples listed, none of them conduct electricity.
For audio and video signals, if it cannot be measured in resistance, it is not a worthwhile process. Everything else you site to show benefit from cryo-freezing is elfin magic, not science. You say you've talked with an RF Engineer or two, but I've talked with multiple metallurgists, and laboratories that do cryogenic freezing. When I tell a metallurgist about this myth, it's all they can do to keep from falling off their chair in laughter.
In fact, the thing that really makes me laugh is I can get a whole box of cables cryogenically frozen in a 72-hour soak cycle for just $20 from the following places:
http://www.pearl-hifi.com/
http://www.ses.soton.ac.uk/projects/ThermalFluid/thermalfluid.html
These guys do it for a living and also admit that there is NO MEASURABLE difference in cables that are done before and after. It's supposed to be this unique process that only a few companies (all audio cable related) know how to do, yet in a matter of minutes, I've found two labs that do it for next to nothing just to earn income. These two labs are actually some of the labs that some of the audio cable companies contract the process out to, so they are not even doing it in house!!!!! Oh, man this is unreal. I can't believe ANYONE would fall for this BS.
As for "strand jumping," the only places that this term shows up in search engines are on YOUR site and a few cable companies, some of which advertise on Audio Asylum.
Strange coincidence?
As for dismissing this nonsense, made up term that has no proof what's so ever, other then the bad-physics you come up with in your articles, my proof is simple.
Energy takes the path of least resistance. You learn this in Elementary School. It is less resistance for energy to continue down its path in a strand then for it to hop to another strand, both of which have an air gap between them and an oxide layer between them. If you actually think that energy will hop over an air gap and oxide layer due to skin effect, you are really loosing you mind. This term is laughable as is anyone who promotes it. Furthermore, you mention that this "strand jumping" is only valid for audio frequencies due to skin effects. Oddly enough, skin effects are based on frequency of which its effects are more noticable at the vide |
| Don't be getting on my case, Jon! - Part II | Kid Charlemagne
Jan 13, 2003 6:56 AM | | I'm getting like Jon now, I need more then one part to reply.
.........Energy takes the path of least resistance. You learn this in Elementary School. It is less resistance for energy to continue down its path in a strand then for it to hop to another strand, both of which have an air gap between them and an oxide layer between them. If you actually think that energy will hop over an air gap and two oxide layers due to skin effect, you are really loosing you mind. This term is laughable as is anyone who promotes it.
Furthermore, you mention that this "strand jumping" is only valid for audio frequencies due to skin effects. Oddly enough, skin effects are based on frequency of which its effects higher at the video frequency range. Why then is it not applicable for video frequency where skin effects can be calculated as higher?
It's likely that the video cable industry would not tolerate such a nonsensical term, or they just haven't thought about marketing their cables that way yet.
I'm glad Steve included it in his article because it brings light to the BS that goes around the cable industry with folks like you.
Lastly, I've read the article and saw your comments. Steve is not talking about silver plating strictly in terms of minimizing skin effect as you will have everyone believe. He does mention that the primary purpose for silver plating is to slow down oxidation of the underlying copper. THIS IS TRUE !!!!!!!!!!!!! In addition to slowing down the process of oxidation, it also provides less resistance in the depth that is calculated to be the "zone" for skin effect, and therefore, IF skin effect is relevant (which the article doesn't say it is), then its effects can also be minimized by silver plating. It is not in conflict, just being taken out of context, but that's what you do. I see nothing wrong with mentioning silver plating as it is a valid process for minimizing oxidation, just as the article discusses.
I commend Audioholics for writing this article. I also recognize that it needs some updating and I'm sure they will do it just as they say they will. Steve openly admitted in this forum and other forums that he WILL update the article to clarify some of the wording and points being made, yet you still continue to attack them.
I still ask myself, why is Jon so concerned that there is another Internet site writing about cables?
More to follow::::::: |
| On The CASE! | Jon
Jan 13, 2003 11:25 AM | | Why not? Where are YOUR references and citations?
You seem to think that resistance is the ONLY criteria for speaker cabls, based on that outdated Roger R. web page. He even encourages people to ignore speaker cbale inductance. Geez!
No there is much more to it than simple resistance, I can assure you that the high end cable bussiness would never be in the state it is in now if that were the case.
RE strand jumping:
Either the stranded wire is acting as a conductor BUNDLE, or it is acting as individual "insulated" wires due to the copper oxide semi-conductor.
As for the air gap, this would only be the case every once in a while, and would not be the case all the time unless the wires were NOT encased in an extruded plastic dielectric.
Most all analysis of stranded wires treat them as if the stranded wires were acting as a conductor bundle, and that current was going to be able to flow across the bundle as well as along the bundle.
I think that your simplistic and one-sided analysis is indicative of just how far you are willing to go to DENY that anything could possibly be going on.
Eddy currents exist within a conductor due to the skin effect, in a stranded wire bundle acting as a more-or-less whole conductor, these eddy currents will tend to force the current flow outward toward the surface of the bundle.
Since a real world wire will not act as a perfect bundle, nor will it act wholly like a completely individually insulated group of seperate strands, there will likely be some impetus provided for some of the signal to jump from one strand to another at various points along the length of the stranded wire.
Note that a very thin stranded wire will not have very much skine efect "pressure" to cause strand jumping, nor will a relatively "thin and flat" section of braided wire, such as most cable braids.
This effect would be worst with a large diameter stranded wire, such as the RG-11 recommended in the article.
My recent reply at Audioholics addresses some of your other comments quite handily.
[ I still ask myself, why is Jon so concerned that there is another Internet site writing about cables? ]
Because they seem bent on a completely naysayer POV, and are getting it technically WRONG.
Jon Risch |
| Hmmmm..First of the MAYSAYERS | jneutron
Jan 13, 2003 12:22 PM | | ""Either the stranded wire is acting as a conductor BUNDLE, or it is acting as individual "insulated" wires due to the copper oxide semi-conductor.""
No..It is never black or white..Has any test been done to verify this condition does indeed exist? Something that would stand up to a "Maysayer" like me?
""Eddy currents exist within a conductor due to the skin effect, in a stranded wire bundle acting as a more-or-less whole conductor, these eddy currents will tend to force the current flow outward toward the surface of the bundle. ""
NO...Eddy currents exist because of the loop currents generated within the conductor bulk caused by the intercept of B dot (rate of change of magnetic field). It is these loop currents which oppose the penetration of high slew rate currents within the conductor. Skin effect is the name given to this "bucking" of the changing current from going into the wire. The phase shift of the eddy currents within the conductor are just that..Phase shifts of the eddy currents.. They do not induce a phase shift on the transport current through the conductor...Just alter the radial distribution.
""Because they seem bent on a completely naysayer POV, and are getting it technically WRONG.""
Some of the things you corrected them on needed such.
But, I'm personally strong enough e/m wise, to know when you or they are standing on thin ice technically. And both of you are.. The discussions are good and informative, the arguments, NOT.
Cheers, John |
| On The CASE! | Suppers_Ready
Jan 14, 2003 12:55 PM | | Jon;
I don't understand how you can say Audioholics has a POV against cables when in fact their guidelines are for properly terminated, well shielded interconects. This is certainly not given to the consumer with stock equipment, thus the consumer will have to go out and buy new cables or fashion their own.
As for your explaination about Eddy Currents, the explaination is correct, but your cause it wrong. It is more of a result of Proximity effect, not Skin Effect. Please brush up on your terms before ranting. |
| Comment/question | Kid Charlemagne
Jan 13, 2003 2:06 PM | | OK, jnuetron is correct, enough with the arguing. I'm putting my "be nice" hat on now.
Jon, I don't understand how you can say there is no air gap between two strands within a bundle and how you can ignore the oxidation of each strand.
Yes, the bundle is located within a dielectric, but the dielectric does not form a hermetic seal around the bundle and therefore, there must be air around, between and in the bundle.
Furthermore, although the strands are 'touching,' there has to be an air gap between them or they would be mechanically fused and no longer individual strands. Even if this air gap is extremly small (which it is), the force required for electrons to cross over the air gap and oxide layers should be greater than the extremely minor forces resulting from skin and eddie, thus preventing 'jumping' between this gap.
Secondly, all copper, plated with silver or pure OFHC, oxidizes. That being the case, each strand, in addition to being seperated by an extremly small air gap, is also seperated by an oxide layer.
Now there are two reasons why the current will continue down its free path of least resistance within its strand instead of jumping through air and through an oxide layer.
Thirdaly, the current flowing down a cable is at the same electrical potential. That being the case, they have no reason to jump.
Now there are three solid reasons why the current will not perform this "strand jumping."
Does anyone else agree or disagree with this? |
| Yah, I know you asked Jon....but | jneutron
Jan 13, 2003 2:32 PM | | There is air in the bundle. But, the wire is twisted, and the twisting process will impart a normal force between the wires. Yes, oxidation will occur, but there will still be sufficient contact to allow conductance between. And it does not require fusion (not atomic fusion, metal fusing).
Only for extreme oxidation, bad environment, extreme age, will the strand to strand conductance fail.
Yes the silver oxidizes, I would worry more about sulfides..All paper and cardboards contain sulfides, and silver sulfide is a bitch to clear.
Current will indeed travel the path of least resistance. Never an argument. For high frequencies, the path of least resistance is tending towards the outer portion of the wire.
The theory of strand jumping does indeed appear to be based on reasonable assumptions. Any conductor that dives from the surface to the inner part of the bundle must have the highs "stripped" as it were, as the depths of the cable are not a hospitable environment for the highs.
When a cable has higher interstrand resistance, the skin depth is affected greatly..This is because the eddy currents being generated REQUIRE radial conduction in order to establish themselves, that is, requires interstrand conduction..So they actually "strand jump". How eddy current strand jumping affects the cable transport currents?? Don't know yet. Workin on that.
I find it plausible that strand jumping of the transport current may exist.. However, I've seen no credible evidence proving it. To consider it reality is at the moment premature.
TTFN, John |
| Yah, I know you asked Jon....but | Suppers_Ready
Jan 14, 2003 10:36 AM | | Sorry John, I respectfully disagree with you that "Strand Jumping" is a real Phenomenon as Jon Risch along with Exotic Audio Cable companies love to promote.
Each strand is at the same voltage potential and thus cannot cause current to "jump". Current jumping only occurs when you have two wires separated by a distance and develop a large enough potential difference between them to cause arching. This is known as the Jacobs ladder. This does not and cannot apply to strands at the same electrical potential within a bundle. There is no proof on this. There is nothing written about it other than on many misleading audio websites such as Jon's.
Jon is a great spin doctor and preys on a market that is primarliy operated by hobbyists with little or no engineering background with hopes to conjur up cable thoeries to justify his self proclaimed position as a cable guru.
I suspect he is employed by many of these companies to write their marketing literature. Of course that is my opinion.
Also, ask yourself, why does he, as well as all of those who promote this fallacy, claim it is only an issue in audio? Skin effect becomes more of an issue as frequency increases, thus why wouldn't strand jumping be an issue in video cables? Also, why is it not an issue in RF for that matter? |
| Yah, I know you asked Jon....but | jneutron
Jan 14, 2003 11:43 AM | | Do not apologize for respectfully disagreeing..no need to. Your point is very good.
I agree the concept is very hard to conceptualize..I'll try (I'll probably fail)
Assume a vary large wire. Inject very high frequency current. Now, at peak current, visualize the current and it's magnetic field. We are talking about a sheet of current on the surface of the wire. Now, the magnetic field outside the conductor is lines around the conductor going CW (for convention, right hand rule)..What about within the conductor, just below the surface, where there is no current? (Remember, very high frequency). The magnetic field is still going through the conductor there, but the field lines are cylindrical in the opposite direction (CCW), parallel to the wire surface, but underneath. Since this is a hf current, this internal field, which is within a conductive medium, is generating loop currents within the conductor. These currents are the currents which are responsible for skinning. It is the conductor's reaction to B dot interception.
Now, if the wire is many stranded, these B dot generated loops cross strands. Using the right hand rule, the field lines within the conductor are your "fingers", and the current loops are as a ring on those fingers.
I do not claim it is an audio only issue. It's also an issue for multistrand superconductor cables as well,,I make no claim as to audibility,,I make no claims that it can even be tested for...And yes, I've seen these websites, interesting fiction at times.
My hypothesis requires high currents, and some within the entire cable, and some trying to stay near the surface. Not a proven hypo, but one I'm trying to test.
RF basically stays near the surface. Regardless of how many octaves bandwidth.
My real question to you...Why no input within my skin thread?? Your input is welcomed.
TTFN, John |
| Yah, I know you asked Jon....but | Suppers_Ready
Jan 14, 2003 12:46 PM | | John;
I am not sure what Skin Effect Thread you are referring to?
What it sounds like you are explaining is more of what is known as Proximity Effect, not Skin Effect. Lets say it was true for the moment, with the caveat being high frequency, current, it still has no applicable impact on speaker cables passing a 20kHz bandwidth. This effect is equally present in solid core wires as it is with stranded wires. It simply reduces current flow thru the wire by decreasing surface area of propogation.
In addition, by simply moving the + - conductors away from each other, the Proximity Effect is nulled and thus is the problem. In most speaker leads (IE. 12AWG Monster) the insulation between + - conductors provides enough spacing for this to not be an issue.
It pains me to see so many audio cable companies (Risch included) promoting fallacies to justify their cables. What is happening here is a perversion of engineering truths combined with star trek physics. This industry seems to be based on too much subjectism with no backbone supporting fundementally sound engineering principles. Where are the consumer agencies to protect people against this fraud? |
| Yah, I know you asked Jon....but | jneutron
Jan 14, 2003 2:26 PM | | I think I pasted it right. but its on this page, just way down.
<a href="/crforum?14@@.ef94f5b">jneutron "Skin effect and wire sound testing" 1/8/03 11:35am</a>
No I'm not talking of proximity effect.
Pay attention to the point where I talk of thinkin caps.
My origional hypo failed to meet one of the tests I considered, and had to re-think the hypo.
Cheers, John |
| Plating, silver or otherwise | jneutron
Jan 13, 2003 3:50 PM | | There are two methods of plating..Electrolytic, and electroless.
Electrolytic deposits much faster, but the rate depends on the geometry forced gradients..Edges plate faster than inside holes for example.
Electroless provides a more uniform coat over all geometries, requiring only adequate bath agitation.
There are bright finishes and matte. Bright includes the use of organic levelers; compounds which cause the "valleys" to fill faster than the peaks..end result, mirror finish. But at a cost...The organics hurt solderability. Under soldering heat, they outgass oxygen.
Matte finish is absolutely the best for solderability, but the price is aging withstanding..The base metal gets oxygen faster, as matte finish is more porous.
For all normal solderable surfaces, both silver and gold plating require a barrier metal be applied, usually nickel..Not much, 5 to 10 microinches is enough (called a "flash"). But required, nonetheless. Otherwise, the plating disappears the instant solder is applied, and you're left soldering to the base metal.
Plated finishes do not prevent base metal oxidation..Even solder plated surfaces. They require fusing of the metal to eliminate porosity. Only solder fuses, gold and silver cannot be fused over the copper. They diffuse into the copper instead, up to 1060 C.
Bottom line..Plated surfaces will still oxidize, albeit at a lower rate.
TTFN, John |
| Plating, silver or otherwise | Suppers_Ready
Jan 14, 2003 12:50 PM | | John;
I believe that was the point the author was making on the Cable article at Audioholics.com that Jon Risch so adamently tried to discredit. It is amazing to see when anyone attempts to write a truthful article about cables, Jon is there to debunk it with his gospel. |
| Plating, silver or otherwise | Jon
Jan 14, 2003 10:23 PM | | You are making two very big assumptions:
1. That the article at Audioholics has no technical mistakes or errors, and that is is perfectly clear in it's reasons for the recommendations it does make.
2. That the points I raise are not valid, or that I am trying to discredit any one person specifically.
First, the article at Audioholics contains some obvious and serious flaws. The fact that the article has been endorsed by mtry, and several other noted cable naysayers is enough to make an intelligent person take pause, and wonder just what it is that they are thinking by endorsing something that is itself, technically incorrect and touting snake-oil.
See the last response by me at:
http://www.audioholics.com/cgi-bin/ikonboard/ikonboard.cgi?s=3e22e89e6652ffff;act=ST;f=4;t=225
So far, no one has provided a response to the main points, or any of the other points I covered in the first post about the articles problems.
Secondly, I provide more than enough technical content in my posts about the article, so that any one with an engineering or technical background can easily see the logic and the basis for the points I raise.
So you see, I do not consider the article by Steve DellaSala, "Component Video Cables - The Definitive Guide" at the Audioholics website to be technically or factually accurate, and I feel it was necessary for someone who knew better to point that out, and to be specific about what exactly were the problems.
If someone writes that there is such a things as a "true 75 ohm" RCA plug, and yet the equations do not back this up, nor is there any practical way to make such a plug have a 75 ohm impedance, doesn't this mean that this was an incorrect statement in the article?
If someone writes that"When a copper conductor is plated with pure silver with a thickness of 50 microns, 92% of the current density will be in the silver. Since silver has a 10% gain in conductance compared to copper, a copper wire plated with silver will have less signal loss especially at longer lengths, thus minimizing skin effect."
and then writes that (in SEC 2.0) "As you will see in Section 2.3, skin effects are minimal to nonexistent in video cables given their frequency of operation."
isn't this confusing at the least? Should we go for silver plated wires (also stranded vs. solid too), or not?
Then there is the classic: " Resistance values of cables becomes significant in lengths well over 2-meters."
which provides the basis for his recommendation of going for RG-11 sized coaxial cables, over RG-6 or RG-59.
Yeah, sure.
And I am full of it?
Get a grip dude!
Silver-plated, RG-11, with stranded wires, and the use of "true 75 ohm" RCA plugs, and not a bit of it makes any sense, based on the very same criteria used to ignore skin effect and other minor cable issues.
Oh, I see, it has to be the right BRAND of snake-oil, must come from the right SOURCE, then it is OK.
Jon Risch |
| Comment/question | Suppers_Ready
Jan 14, 2003 1:00 PM | | Shhhh Kid, can you please stop posting sensible replies. I am enjoying Risch fictional story telling capabilities. When you post such truths, its like telling a kid there is no real santa claus. Oh BTW, don't forget to elevate your cables :) |
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