A D.I.Y. Speaker Cable

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  • JonMarsh
    Mad Max Moderator
    • Aug 2000
    • 15311

    A D.I.Y. Speaker Cable

    This is about a little "test" project that I just finished. I wanted to take a stab at putting together a "budget" set of high end cables for evaluating the M8 MKII currently in development. To understand where this is coming from, the goal was to make a full range speaker cable with as much of the general quality and neutrality of top end cables like the Cardas, with a performance goal somewhere between Cardas Quadlink Speaker cable and Cardas Neutral Reference Speaker cable. And of course, at much lower prices! The "budget" standard of reference I'm currently using are some DH Labs Silversonic based cables, which are quite respectable for the moderate cost per foot of the bulk cable. I also use this cable for internal wiring in speakers systems in some cases. So, my plan was to make a cable of the same length as the ones I have, and compare the two.

    What else? How about readily customizable to the specifics of an installation- that is, for some amplifiers and speakers, either spades or bannana plugs may not be an option. For example, my Ayre V-5 uses a Cardas clamp binding post assembly which won't work with bannana plugs; spades are a must. In other situations, requirements may be reversed. Plug and Play connectors, which means WBT; there really aren't any alternatives I've found with similar flexiblity. For "fixed installation" cables I favor Cardas connectors, but they are always soldered.

    What's important in a speaker cable?

    This is an interesting and non-trivial question; you'll get as many different answers as there are cable companies, I think. Some fundamentals I think we can hold true, though, laying aside some of the mumbo jumbo and slick talking brochures.

    First, the lower the resistance, the better- this is especially true for speaker runs over two meters. This generally means that we'll be looking for aggregate wire guage of 14 AWG or lower, depending on the cable lenth.

    There are some interesting cable "receipes" available on the 'Net- probalby some of the best known are Steve Rochelin's. Many have reported satisfying results making hand braided speaker cables, (which reqiures the larger part of a whole weekend!), but me, I'm just not that masochistic. However, I've worked with braided cables to reduce inductance and RFI pickup since the 70's, and purchased the first "tweak" cables that I'm aware of using this technique in the mid seventies; they were imported from Japan by Polk Audio, of all people; I still have some of that magnet wire based cable around. But for this experiment, after researching what was available and what I could find to buy in bulk, I settled on Kimber 8TC bulk cable. This uses eight very high purity copper conductors with teflon insulation for each polarity of the signal, in a woven matrix to reduce inductance and RFI pickup.



    The aggregate resistance of this cable is rated at 9 AWG. This seems to meet the resistance goal. The woven braid reduces inductance considerably compared with twisted or parallel pairs- how much, we'll have to wait and see when the finished cables can be measured.

    For the flexibility of their crimp and Torx screw connection system, I chose a set of WBT spades and locking bannana plugs. The actual work involved here is not that bad- first, unweaving about 4" of cable, and stripping the ends by seven tenths of an inch to prepare for the crimping and soldering operation.



    After stripping and twisting the cable halves, a crimp tool is used to crimp the bare copper leads into a WBT AWG 8/10 crimp sleeve. There is a bit of excess space, and a handheld tool doesn't really produce a high quality gas tight crimp, so I follow up with Cardas Quad Eutectic solder fed into the open end of the crimp assembly. The Quad Eutectic solder is made with lead, tin, copper and silver. It's strongest property is that it doesn't slurry when cooling, and it makes virtually absolutely perfect solder connections every time. This stuff is the best, in my opinion; I don't use anything else any more, for anything.



    The next step, nearly finished, is heatshrink protection for the wires- I like the Kimber wire colors, and maintained that with my choice of heatshrink.



    For protection and to avoid pickup up dust or dirt in the cable, I also sheathed the finished cable with Alpha polyester braid; I popped for the more expensive GFP 120NF 12 braid, which is "anti-fraying", and doesn't require a hot knife to cut. Here is one of the finished cables:





    How well do they work?

    First, I did some basic measurements of the DH Labs based cable and the new one. I measured the inductance in "loop back" mode, that is, it measures the inductance at one end, with the other end shorted together. This gives a good measure of the series inductance which the amplifier/speaker combo sees with a given cable.
    Then, I open the far end of the cable, and measure the capacitance. This gives a measure of what added capacitance the amplifier must drive; unfortunately, most power amplifiers should be happy with at least a few nanofarads of capacitance at the output terminals, however, some high feedback designs don't even tolerate that well. Last, for comparison, I measured the resistance of one leg of the speaker cable- this can be doubled for the total resistance in series with the speaker.

    Measurements were made with my HP LF4192 Network analyzer; this is a really useful little critter, as it can measure at a wide range of test frequencies ( from 100 Hz to 5 MHz), and with or without bias voltage (adjustable) applied. It is a four terminal (kelvin) tester, with several test heads, so their aren't errors introduced from test leads.

    The results were interesting, but actually a bit better than I expected.

    DH Cable, 14 ft:

    Loopback Inductance: 3.25 uH
    Distributed Capacitance: 0.453 nF
    Resistance one leg: 0.16 ohm
    Resistance both legs: 0.32 ohm


    8TC based Cable, 14 ft:


    Loopback Inductance: 0.35 uH
    Distributed Capacitance: 1.36 nF
    Resistance one leg: 0.033 ohm
    Resistance both legs: 0.066 ohm


    This shows a nice combination of characterisitics, as the inductance is cut by an order of magnitude, while the capacitance is only increase by about 3, and is still quite reasonable in value. The resistance speaks for itself.

    How do they sound? I have only had a brief opportunity to do any comparitive listening; I put a CD (jazz; "Classical Soul", ), played the whole disk, then swapped cables (without touching the stepped attenuator on the preamp) and played the disk again. My initial impression is that the bass with the new cables is deeper, better controlled, and slightly higher in level. More important, the midrange and top end seems more coherent, smoother, and less dark or hard. With the silver DH cable, it's as if there's a slight tip up to the sound, peaking around 3-5 kilohertz, with a slight roll off above that, and with some slight veiling in the midrange, plus the lighter bass. This could *all* be placebo effects, too, but extended listening will probably tell.

    I'll have to get back with you on this one, folks, but so far, I think the results are close to what I hoped for.

    Best regards,

    Jon







    After




    Earth First!
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    the AudioWorx
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    In Development...
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    Resistance is not futile, it is Volts divided by Amperes...
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  • ThomasW
    Moderator Emeritus
    • Aug 2000
    • 10933

    #2
    The results of the measurements are quite interesting......

    Your job now is to find us a wholesale source for the Kimber wire




    theAudioWorx
    Klone-Audio

    IB subwoofer FAQ page


    "Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson

    Comment

    • JonMarsh
      Mad Max Moderator
      • Aug 2000
      • 15311

      #3
      I've since done some tests, simulations, and measurements, and just the difference in inductance between the two cables can make a significant (audible, measureable) difference in the top octave response of most speakers, and may reduce interaction with reactive crossover networks at lower frequencies, too.

      So yes, the next step is to find the best bulk cost on the raw cable.

      -Jon




      Earth First!
      _______________________________
      We'll screw up the other planets later....
      the AudioWorx
      Natalie P
      M8ta
      Modula Neo DCC
      Modula MT XE
      Modula Xtreme
      Isiris
      Wavecor Ardent

      SMJ
      Minerva Monitor
      Calliope
      Ardent D

      In Development...
      Isiris Mk II updates- in final test stage!
      Obi-Wan
      Saint-Saëns Symphonique/AKA SMJ-40
      Modula PWB
      Calliope CC Supreme
      Natalie P Ultra
      Natalie P Supreme
      Janus BP1 Sub


      Resistance is not futile, it is Volts divided by Amperes...
      Just ask Mr. Ohm....

      Comment

      • JonMarsh
        Mad Max Moderator
        • Aug 2000
        • 15311

        #4
        We used these cables at ThomasW's last week for evaulating and refining the pair of M8 MkIII's he and Pete built a few weeks ago- I've left them with ThomasW's so he can do some further listening if he wishes. The results were compelling in the system we setup in his main listening room:


        Transport: Sony SCD777ES
        DAC: MP-DAC (NLFB)
        Preamp: Creek P43R passive preamp
        Amp: Ayre V-5 (NLFB)
        Speakers: M-8 MkIII's, with stands


        Other cables were custom made using Cardas and WBT connectors with Cardas cable.


        One listener, who had listened to this pair of speakers for a week in his own system, with very specific setup instructions, said that they sounded "worlds better" in the system in ThomasW's living room. Too many variables to lay a definitive explanation, but nonetheless instructive, as he thinks he has a pretty good system.



        Regards,

        Jon




        Earth First!
        _______________________________
        We'll screw up the other planets later....
        the AudioWorx
        Natalie P
        M8ta
        Modula Neo DCC
        Modula MT XE
        Modula Xtreme
        Isiris
        Wavecor Ardent

        SMJ
        Minerva Monitor
        Calliope
        Ardent D

        In Development...
        Isiris Mk II updates- in final test stage!
        Obi-Wan
        Saint-Saëns Symphonique/AKA SMJ-40
        Modula PWB
        Calliope CC Supreme
        Natalie P Ultra
        Natalie P Supreme
        Janus BP1 Sub


        Resistance is not futile, it is Volts divided by Amperes...
        Just ask Mr. Ohm....

        Comment

        • Lex
          Moderator Emeritus
          • Apr 2001
          • 27461

          #5
          Nice job Jon. Those are amazingly close in appearance to my new Quantum speaker cables, outside of the fact 8 strands are silver on those. (I am talking about the raw wire, not the finished product) Since you cover yours, and I don't mine.

          It is a nice wire design, with mine similar to the Kimber, but I am sure slightly different. I was working on being able to supply some Kimber raw materials, but so far, that hasn't happened.

          Lex
          Doug
          "I'm out there Jerry, and I'm loving every minute of it!" - Kramer

          Comment

          • Brian Bunge
            Super Senior Member
            • Nov 2001
            • 1389

            #6
            Jon or Lex,

            Can you explain how you braid cables together when you are using 4 or 8 conductors per side? I understand "normal" braiding using 3 conductors, but don't understand when you use something other than multiples of 3. I have a bunch of silver coated copper cable and wanted to try it myself!

            Thanks,

            Brian

            Comment

            • Lex
              Moderator Emeritus
              • Apr 2001
              • 27461

              #7
              Brian, I could help with unbraiding that many, but braiding is a different story. Mostly it's done by machine. Sure, there's a pattern, but I really don't have it.

              Lex
              Doug
              "I'm out there Jerry, and I'm loving every minute of it!" - Kramer

              Comment

              • ThomasW
                Moderator Emeritus
                • Aug 2000
                • 10933

                #8
                Braiding wire? No mystery to that. Here's a link, understand that 6/8 braiding is the same pattern as 3/4




                With wire it's important NOT to use a fixed clamp to hold the starting end wires. They need to be free to rotate. If clamped the insulation will 'cold-form' as it twists around the conductors. This loosens the adhesion between the wire and the insulation.




                theAudioWorx
                Klone-Audio

                IB subwoofer FAQ page


                "Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson

                Comment

                • Brian Bunge
                  Super Senior Member
                  • Nov 2001
                  • 1389

                  #9
                  Thomas,

                  So how do you "anchor" the wires at the starting end?

                  Brian

                  Comment

                  • ThomasW
                    Moderator Emeritus
                    • Aug 2000
                    • 10933

                    #10
                    Brian

                    Trust me it's safer for dyslexic Norwegians (yours truely) not to braid anything. If I hung myself no one would believe it was an accident :B

                    Have a second person help when getting the braiding started. That person can hold the ends but allow them to freely spin as the braid is started. This will waste about a foot of material, but won't stress the bond between the wire and the insulation. The goal is to avoid getting air inside the wire. If either the raw wire or insulation rotate against the other, air gets inside the wire. This results in less than optimal performance.




                    theAudioWorx
                    Klone-Audio

                    IB subwoofer FAQ page


                    "Complicated equipment and light reflectors and various other items of hardware are enough, to my mind, to prevent the birdie from coming out." ...... Henri Cartier-Bresson

                    Comment

                    • Brian Bunge
                      Super Senior Member
                      • Nov 2001
                      • 1389

                      #11
                      Thanks Thomas!

                      I actually thought that I'd just hold the ends while I get my wife to start the braid (she was going to do the braiding anyway!). Nice to know that my idea wasn't so stupid after all!

                      Brian

                      Comment

                      • Lex
                        Moderator Emeritus
                        • Apr 2001
                        • 27461

                        #12
                        Thomas, what I didn't say was 3 wires is all I braid, and there is no mystery for me either. I do it all the time. I learned on my daughter's pigtails years ago.

                        Goodluck Brian,

                        Lex
                        Doug
                        "I'm out there Jerry, and I'm loving every minute of it!" - Kramer

                        Comment

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