CAT5 Speaker Cables?

[SpinWheelz]

No doubt some of you are familiar with the use of CAT5 wires as speaker cables. I thought it was a simple case of stopping by Home Depot and our local home improvement store and picking a ton of CAT5 wire. Had no idea that there were different kinds of CAT5 wire. From what I've read I do know that I need 4-pair CAT5 wires. But one thing I've not been able to learn more about is the difference between Plenum and non-Plenum CAT5 wires. The Plenum CAT5 wires cost over twice as much per foot versus the conventional non-Plerum variety.

Does anyone have any insight on the Plenum CAT5 variety versus the conventional CAT5 wire? Are the Plenum CAT5 wires worth the premium? More importantly, I wanna make sure that I don't end up paying more for an inferior wire.

Any help would be greatly appreciated. Many thanks!

[SpinWheelz]

Addendum:

I've seen STP (shielded twisted pair) CAT5/6 wires and some which are UTP (unshielded, I presume?). What gives between these two? Which is preferable?

[skeptic]

From what I've read I do know that I need 4-pair CAT5 wires. But one thing I've not been able to learn more about is the difference between Plenum and non-Plenum CAT5 wires. The Plenum CAT5 wires cost over twice as much per foot versus the conventional non-Plerum variety.

Does anyone have any insight on the Plenum CAT5 variety versus the conventional CAT5 wire? Are the Plenum CAT5 wires worth the premium?

In 1979 in a tragic fire at the Stouffer's In in upstate New York, half a dozen top executives from Arrow Electronics of Sunnyvale California on a business trip were killed. They didn't die from the flames, they died from a thick black choking smoke that resulted from the breakdown of PCV wire insulaton and other materials in the return air plenum above the drop ceiling and was spread by the air conditioning system. When these men breathed those fumes they were knocked out cold and died soon afterwood from the smoke.

Shortly after the fire, the National Electical Code was changed and PVC was prohibited from being installed in return air plenums above ceilings. (PVC can be installed in metal raceways like conduit in such a space however and it can still be installed in supply plenums below raised computer floors.) A host of wire products came on the market bearing the legend that it complies with the applicable provision of NEC for smoke and flame spread. Most are various forms of Teflon but some are other materials such as Halar. Beyond this application, some people who worry about the properties of insulation of wire acting as a dialectric (forming a capacitor between conductors) claim that teflon is audibly superior to PVC. Although this makes little sense to me for audio use, those people who advocate these exotic cables make this claim so I figure you should know. If you want the real low down scoop, visit an electrical supply house and get yourself a Belden Catalog. If they don't have one, ask them to order it for you or you can go to their web site. They are one of the world's leading authorities as well as one of the leading manufacturers of wire and cable of all types and most of their competitors cross reference their catalog numbers and specifications.

Cat 5 refers to the low capacitance telephone wire used for high speed data networks in office and manufacturing buildings for those users who prefer it to other types of LANs. Currently it is in vogue. These networks are designed to carry up to 100 megabits per second with cat5 E cable in runs of 250 feet or less from the router. (the routers are tied together by a fiber optic backbone.) This is very thin cable so the diy projects usually require you to buy enough for many lengths of it and use it in multiple parallel arrangements. Be careful. Although each has very low capacitance by itself, when you combine them, you may be building one fairly large capacitor. One guy posting on CA a long time ago complained that the one he built blew up his amplifier. Was it the capacitance causing it to go into spontaneous oscillation as I speculated or was it a strand from one conductor accidentally touching another and causing a short as other posters insisted? I don't know but amplifiers are usually designed to survive dead shorts from speaker hot to ground. Most are not designed to drive a strongly capacitive load.

Frankly, the whole thing sounds to me like a great big waste of time and money but it's your time and your money so......

[Mwalsdor_cscc_edu]

The Plenum CAT5 uses a TEFLON dielectric.Here's some threads on fellas that have experience constructing and had success using CAT-5 in their system.MikE

http://AudioKarma.org/forums/showthread.php?s=&threadid=5019&highlight=cat5 http://AudioKarma.org/forums/showthread.php?s=&threadid=11647&highlight=cat5 http://AudioKarma.org/forums/showthread.php?s=&threadid=8&perpage=15&highlight=cat5&pagenumber=1 http://audiokarma.org/forums/showthread.php?s=&threadid=8440&highlight=cat5

[Beckman]

I am embaressed to say I made some CAT 5 cables per TNT-Audio's technique. I thought at first they sounded good, but after a couple weeks I switched back to 12 AWG zip. After the switch back to zip the bass was noticably tighter and the treble sounded better. In my experiance all CAT 5 cable did for me was severly degrade the signal.

[skeptic]

You could probably get the same effect by adding an inductor and resistor in series and a capacitor across your speaker. Basically, if you did anything, it was to roll off both the high and low end while increasing resistance and therefore reducing effective amplifier damping factor adding some boominess. For people with a bright sounding audiophile 8" two way ported system, this might seem like an improvement but it is risky IMO and not the right way to go about making things better.

It is absurd to think you can reliably "manufacture" your own speaker cables and maintain any kind of predictable electrical parameters. In a factory, not only the materials but the dimensions of the insulation, the wire, their spacing which are all critical to electrical properties are under very tight control. At home of course, there is NO control. I still believe that the guy who posted on CA a few years ago that his amplifier blew up after a DIY Cat5 speaker wire project created a tank circuit which sent his amplifier into spontaneous ultrasonic oscillation. If this is true, he was lucky he didn't blow out his tweeters as well.