Perfect, what would happen if you stacked a copper plate on top of a zinc plate using a peeled potato between them as dielectric ? Inquiring minds want to know : ) Sean
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It should probably be pointed out that the corrosion visible through a clear jacket maybe wasn't caused by the jacket itself, but was the result of such an old cable's having been made using copper that was not pure by today's standards. My head hurts now.... |
I use to work with copper that was 99% pure. We worked with copper plates and I noticed a few things. If copper gets wet it will start to show corrosion in as little as twenty minutes. Im not talking under a micrescope but right in front of your eyes.
Second if the plates were stacked on top of each other they would stay shiny for several months, even over a year, but if left in the open they would start to tarnish and dull in just a couple of weeks.
I dont know what any of this means but I thought I would pass along the observation. |
We could all go nuts. I can imagine there is a cable out there that does not sound good (bright, analytical), degrading with age to the point that it does sound good. |
Sugar, once again you bring up some good points and this thread is expanding in a "good" way.
I also agree with your comments concerning technology advancements and the increased quality of materials used in the production of wires / cables. Only problem is, how much of what "scientists" know about dielectric materials is actually being applied to the products that we as audiophiles are buying ? We are told that Teflon is "king". Is that really true ?
As to silver corroding, silver oxide is supposedly highly conductive ( from what i've been told ). As to your comments on gold, i have no idea. I am far from knowledgeable when it comes to metallurgy. However, i do have to wonder what happens to both of these materials ( along with copper ) when exposed to other materials such as the dielectric that is decaying ? Is there some type of "chemical reaction" between the metal and plastics that causes surface decay / increased skin effect ? I have NO idea.
As i mentioned, the only way to get around this type of problem is to use what is called a "non-contaminating" or "Type II" dielectric material. This boils down to the fact that the plastics being used to make the jacket are of a stable molecular structure ond don't "bleed" over time. I don't know if this is applicable to Teflon or not.
I've been told that using a foil shield between the conductors and the outer jacket helps drastically reduce the effects of plasticizer migration from the outer jacket into the conductors though. The foil simply acts as a "barrier shield". Even doing that would not solve the problem as individual stranding would still need some type of insulation to keep from shorting out internally. As such, the wires would still be surrounded by some type of dielectric that was susceptible to "plasticizer migration".
I think that enameled wire is looking better and better the longer that this thread continues : ) Sean
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I completely agree with you Sean and others. It is just my opinion that the typical generic "clear" jacket cable is so poorly made, it is going bad the minute is leaves the factory. I would not recommend it brand new, so used is a non starter. On the other end of the spectrum, I have re-terminated older high quality cable. When I cut the ends off and stripped down some of the covering, the copper cable under there was as shinny as new. Quality cables is a recent event. Most cable brands out there are less than five to seven years old. I would not consider any of them old yet. Some of the very oldest MIT music hose from 1985 may be a risk, but has anyone cut then open or tested them to see? The MIT Terminator series only started in 1994 (white jacket); the ones with the grey jacket are only a couple years old at the most. The original poster did not specify copper cable. Silver cable is another story completely. As well as silver/copper strands like Nordost and others; and gold/silver cable like Siltech. These types of cable should last a lot longer than copper. It is my understanding that silver is still a good conductor when it tarnishes. Gold's conducting properties will be the same a million years from now. |
I have seen and heard for myself what Sean describes about oxidation over time that is visible through a clear PVC jacket, and the degradation is quite audible. I imagine that this eventually happens to a greater or lesser degree with any cable. But it seems to me that a Litz-type (individually coated fine strands of wire within a braided geometry) cable, such as the Cardas I use, should have the longevity advantage. |
Sugar, you're missing the point. It is NOT a matter of whether the cable is "air tight". For one thing, it would be next to impossible to achieve without DRASTICALLY raising the cost. Nor does it really matter how tightly the stranding is compacted within the jacket. It is a matter of the materials used as the insulator and the degradation that the JACKET undergoes with time. If you don't believe this, contact Belden or any other manufacturer of cables.
If one has the proper test equipment ( TDR aka Time Domain Reflectometer ), you can also measure the electrical characteristics of cables and compare new samples to old samples. The impedance characteristics, levels of dielectric absorption, velocity factors, etc... of cables DO change over time, albeit very gradually. These rates can be accelerated by exposing the cables to various levels of direct sunlight, fluxuating temperatures, different levels of applied pressure, etc...
Besides that, the originator of the thread made no mention of price range. With that in mind, we all know that a LOT of cables are simply "dressed up" versions of mass produced cables. As such, the "KLH" vs "Mark Levinson" pricing analogy has little to do with "you get what you pay for" i.e. "quality" when it comes to cables.
While one would hope that more expensive cables from a reputable brand made use of better quality materials and had a greater amount of research and development in them than cheaper cables from some generic company, there really is no guarantee of that unless specified as such. Even then, i've seen companies PURPOSELY mis-label products so that they could charge more for them even though they knew that they would not meet spec. Since the average end user would have no way of verifying spec, they get away with it 99% of the time.
Like anything else, let the buyer beware. Sean
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PS... I've bought and used many older cables. So long as they make a good connection and sound good to your ears with no potential for damage to your equipment, i would not worry about it. I was "debating" from a purely technical standpoint. |
Albert: Next time try wine, candles, and Ravel's Bolero. |
Yes cables become too old at some point. I had two pair of very old Purist cables, one was 10 feet long, the other 8 feet long.
I placed them in a dark cozy environment for several days, hoping for a baby Purist cable (at least 2 feet long), but even with Handels' Water Music playing softly in the background (their favorite) NO BABY CABLE.
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I hope there is some assumption of quality. Just because 25 cent per foot Monster cable oxidizes in the jacket, does not mean much. I would not consider that monster stuff air tight. It is pretty easy for even a child to pull the copper wire out of the plastic cover of Monster cable with a pair of pliers. Try doing that with a run of JPS Labs Super 2s, or any high end cable. You could tow a train with some cables. The capacitors in a $79.00 KLH receiver from Circuit City may go bad after two years. It does not imply that the caps in a $20,000 pair of Mark Levinson mono-block amplifiers will go bad that soon (or any other high-end gear); and we better only buy new stuff. |
Sugar, have you ever looked at the color of the copper in some clear jacketed "monster" type cables after a few years and compared this to brand new cable ? It is definitely darker. Some of this has to do with the type of materials used within the jacket itself though. The plasticizers in the jacket tend to "leak out" and taint the conductors. One would have to use what is called a Type II mil-spec jacket to alleviate this type of problem. Even then, corrosion would set in over time as nothing that is man-made will last forever. For all practical purposes, this would take a LONG time though, especially if the open ends of the cable were properly prepped i.e. "sealed".
I do agree that wire that is exposed will tarnish FAR, FAR faster than wire that is protected, especially when exposed to varying levels of humidity. Sean
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The copper inside a cable's jacket is not expose to air and therefore cannot oxidize. It should be fine for a very long time. When you buy cable it does not need a "freshness date". Only if you are using bare wire, the exposed ends as Garfish mentions can oxidize. The ends can be tinned with silver solder to stop the oxidation. Silver will oxidize, but is still a good conductor. Those ends can always be re-done every few years. You'll only lose an inch of cable each time. If the cabes have copper spades connections, etc, they can be cleaned (as per Garfish). |
All copper oxidizes with age. This is pretty easy to tell though, as if it is still relatively shiny, it's still "fresh". When it is getting darker and loses brilliance, it is time to either replace or reterminate. Sean
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I'v had my big rig all copper speaker cables 6 years, and another pair 8 years, and as far as I know they sound as good (or better) as when well broken in. And I used a 25 year old length of 6 ga stranded copper as a mainline for a dedicated system, and it sounds great. It was previously used as wire for an ARC welder which used huge amounts of current when actually welding-- just helped to break it in I think;>) Personally, I think as long as end points/contacts are kept clean, copper will last a LONG time. Cheers. Craig |
