Thursday, September 8, 2011

Fancy Cables and Dielectrics

Perhaps it's no surprise that each high end cable company has a different story.  Most typically, it's a story about they have discovered something unique that no other cable company pays attention to.  Thus there are an infinite variety of different labels and buzzwords used by each company, no two the same.  They want to make you a true believer, not a careful comparison shopper.

Meanwhile it's often very hard to find out the basic facts about each kind of cable.  For starters, the facts of interest to real audio engineers would be:

cable impedance: resistance, capacitance, and inductance
shielding: none, single, double; braided vs foil; coverage percentage

Some additional facts are generally recognized by audiophiles and some engineers:

dielectric material: vinyl, polyethylene, teflon (from worst to best...this affects a parameter known as dielectric absorption, which is not ordinarily specified, and may even defy a single number specification, but if you know the dielectric you can make some predictions about dielectric absortion, teflon being the best and better than vinyl by 10-100x, and polyethylene being closer to teflon than vinyl)

general geometry: twisted pair, coaxial, shielded twisted pair, multi-conductor ribbon, hyperlitz, etc. (but the virtues of the geometry would also be revealed by a full accounting of the impedance and shielding effectiveness anyway).

Anyway, these are generally not the kinds of facts you get in the descriptions of most high end cables, even if you go to the "specifications" page.

I have even found two significantly different descriptions of the same cable, the Audioquest Copperhead.  The description at Amazon.com claims the dielectric is polyethylene, and the description at AudioAdvisor says the dielectric is a specially chosen PVC (aka vinyl).

Sorry, but I won't pay a high cable price without the cable company being very straightforward with me about what I am buying.  I might be impressed by Audioquest's "PSC" (TM, perfectly smooth copper) as an interesting treat, but if it's merely used on plain old vinyl wire, I'll pass.

I'm now looking to upgrade some if not many of my old vinyl and not well shielded Radio Shack cables (which have now become quite expensive) with better shielded cables using polyethylene and teflon.

Teflon cables, it turns out, are often very expensive.  Leading manufacturers of audio cables with teflon dielectric are Cardas and Nordost.  These are companies known for making multi-kilobuck cables, but they also make relatively affordable ones also, if you consider a $150 cable affordable.

Yesterday I finally ordered my first Cardas cable, and 0.5 meter Crosslink interconnect, priced at $128.  It uses teflon dielectric (actually the entire insulator is teflon) and Cardas' trademark golden ratio litz (litz prevents noise causing strand interactions and decreases self inductance and skin effect), in a multiconductor inductance cancelling geometry, with good shielding.  I plan to use this for one of my few actual analog sources, my Pioneer F-26 tuner.  If I like it, I'll get more.  Unfortunately, it's on back order.

I also another audio cable from Blue Jeans cable.  Blue Jeans generally uses standard designs from Belden and Canare (the world's two leading industrial cable manufacturers) with very nice RCA's from Taversoe or Canare with gripping metal fingers inside.  Now they also offer some exclusive cable designs, typically made by Beldon under special order.  Most of their cables use polyethylene dielectric, which is common among industrial cables (for example, broadcast use).  Many of their cables use solid conductors (which improves impedance consistency under bending--the official reason, and also reduces noise from strand interactions--a more tweako concern.)  I like their cables a lot, but they are often fairly (or even extremely) stiff, stiff enough to lift light equipment like my home built notch-blend filter, which is one reason why I'm checking out the Cardas.  Plus, the Cardas has Teflon.  But I also ordered some 2 foot long LC-1, their latest custom audio cable design built by Belden to be more flexible.

Kimber makes a less expensive interconnect cable with teflon insulators called the Hero, but it is unshielded.

Mogami is another industrial cable manufacturer like Canare and Belden.  They make cheap interconnects (now actually cheaper than the cheapest from Radio Shack, and clearly for home use...) and various midlines.  The midline versions use polyethylene. I'm ordering some WR-01, WR-03, and WR-06.


2 comments:

  1. Thanks for sharing the information, it was of great help. We can get an idea of different types of cables and which ones should we opt for.

    ReplyDelete
  2. Thanks for sharing such an informative blog,I have really became very much satisfied by viewing this blog.

    ReplyDelete