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The Cable and Wire Page

 

  Interconnect and Speaker cables
   
  I have experimented with various kinds of speaker cables and interconnects over the years. I used to use standard 18 AWG "zip" wire for speaker connections, and the thin cheap-o interconnects that come with commercial low- to mid-fi equipment. I didn't know any better.  
   
  Interconnects  
   
  For interconnects, I tried braiding thin (30 AWG) magnet wire (described, for example, here). It sounded a little brighter than the cheap-o cables, but the wires were very delicate and difficult to manage in the rat's nest behind the equipment. God forbid they should short-out and blow the amplifier.  
   
  I was fortunate to have come into the possession of a small amount of leftover Belden plenum network cable that was used to set up a network in an office where I worked years ago. As it turns out, this kind of cable is ideal for making very high-quality interconnects and speaker cables. The cable is coaxial, low capacitance, has both a foil and a braided shield, has Teflon insulation, and a Kevlar jacket (see the specifications at the bottom of the page). I followed Jon Risch's detailed instructions for building the interconnects and speaker cables (also here).  
   
  Interconnect Connections
   
  For the interconnect connectors I used Radio Shack gold-plated RCA plugs. I don't think the gold makes any difference in the sound, but they won't corrode over time, and I think corroded connections can make a difference in the sound. The Radio Shack plugs are the cheapest gold-plated plugs I could find (about $3.00 each).  
   
  Speaker Cables  
   
  My first experiment with improving my speaker cables, many years ago, was to buy 12 AWG "Monster Cable" (still "zip" wire, just very expensive zip wire). That seemed to make an improvement, especially in the bass.  
   
  Then, I tried braiding CAT5 network wire (described, among many other places, here), and that may have sounded better (hard to tell), but the braided wire is bulky, ugly, and unwieldy. Also, it generates high levels of capacitance from all those wires that is not good for the amplifier.  
   
  Now I use speaker cables made from the Belden coaxial cable discussed above in the "Interconnects" section. At least, I use the Belden cable for the tweeters anyway; see the "Bi-Wiring" section, below.  
   
  The speaker cables use two pieces of coaxial cable for each lead. The wires are crossed in such a way that the conductor of one and the shield of the other carries the (+) signal, and the shield of the first and the conductor of the other carries the (-) signal. For connectors, I used Radio Shack gold-plated banana plugs.  
   
  And then... Bi-Wiring  
   
  After living with the above setup for a year or so, I decided to make a change. Because I built my new AR.com speakers with two sets of speaker terminals so I could experiment with bi-amping (which didn't work out so well), I decided to try bi-wiring instead.  
   
  The theory behind bi-wiring is that by branching off from the amplifier and using separate cables for the runs to the woofer and tweeter circuits in the speaker crossovers, the inductance and capacitance that is generated by the relatively higher currents in the woofer signal do not affect the lower-powered tweeter signal. Thus, the more delicate tweeter signal is separated in its own cable and is not damaged as it would be if the woofer and tweeter signal were traveling in the same cable.  
   
  I modified the AR.com's crossovers so that the woofer and tweeter circuits were independent, and did not share grounds, and hooked each circuit up to its own set of speaker input terminals. I then used the Belden speaker cables described above for the tweeters, and my old 12 AWG Monster Cable for the woofers.  
   
  Cable Termination  
   
  After reading Rod Elliot's article on cable impedance I decided to add a 100 nF ceramic capacitor in series with a 50 ohm resistor across each speaker terminal to properly terminate the cable and dampen the high frequency phase anomalies caused by cable reflections. His testing of "DIY Cross Connected Coax Cable", which is exactly what my cables are, found a huge phase anomaly at 10 Mhz and other cable reflections at 100 MHz. The addition of the resistor-capacitor "Zobel" termination network completely eliminates the anomalies.  
   
  Conclusions  
   
  How do these cables sound? Although there is a lot of controversy over whether so-called "boutique" cables really make an audible difference, I like to think that the Belden interconnects sound a bit better and less harsh than the braided magnet wire ones, and the Belden speaker cables sound maybe just a little smoother than the braided CAT5 ones. At least, they are easier to use. It's hard to say if the bi-wiring improved the sound, but like so many other "tweaks" I've made, I can't see where it could have made things worse. However, both definitely sound significantly better than the crappy connector cables and thin "zip" wire speaker cables that come with mass-market stereo equipment that I used to use.  
   
 Black line 
   
   
Cable Specifications
  
MakeBelden
ModelCoaxial Plenum Network Cable model 89907
Conductor20 AWG Tinned Stranded Copper
Conductor Insulation.095" Cellular FEP (Teflon)
ShieldFoil and 93% Tinned Copper Braid
JacketKevlar
Impedance50 ohms
Inductance0.0635 uH/ft
Capacitance25.4 pF/ft
Velocity of Propagation80%
Shield DC Resistance5.8 ohms/1000 ft
Conductor DC Resistance8.8 ohms/1000 ft

 

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