Instructables

How to make a Transparent Audio Reference XL Speaker Cable

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Step 3: Build the main network

Transparent's main "network" is simply an inductor measuring 2.5 micro Henries that is soldered into the path of the positive leg of the cable.

To make the inductor, take a two inch long piece of your oak dowel and wind your 14 gauge solid copper wire tightly around the dowel.  In order to get precisely 2.5 micro Henries, you will need something more complex than a multimeter.  I went to my buddy's shop and used his LCR meter to measure mine.

Side note: My opinion is that you don't have to make it too precise because a 2.5 micro Henry inductor really doesn't add very much inductance anyway.  When I measured the cable without the inductor soldered in, it measured 3 micro Henries by itself.  So, without the inductor, if I wanted to add 2.5 micro Henries of inductance, I just needed to lengthen the cable by about 8 feet.  Anyway, back to the instructions.

I found that if I wound tightly, I consistently got 2.35 to 2.55 micro Henries with 18 turns around the dowel.  I think that's a good rule of thumb to go by if you don't have a complex instrument to measure the inductor.

Once you're satisfied with your inductor, use masking tape to hold it in place around the dowel.  Tin the ends so they'll be easy to solder later.
 
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Bob Sm7 months ago

FYI, Transparent doesn't use your buddy's measurement equipment. They first use vastly more precise equipment that measures down to a 1/100th of a ohm, etc. and they use an entirely different cable than you can buy off the street. They also match the components to the cable and cable length, so just buying off the shelf cable and making an inductor that measures between 2.35 and 2.55 isn't going to be the same thing. I think your winding isn't tight enough, which might lead to the different measurements. Inductors usually have to be tightly wound and to not cause any ringing either.

I would first find out what test equipment these companies use, examine their actual cable since they have specific cable geometry, dielectrics, winding, and cable mfg which yield a specific end result and then they design the network around the cable and which frequency range they are trying to "neutralize", if you will. Good try though. Plus, how new is the cable in question that this was modeled after? Do they make the exact same design? They have introduced new product designs over the years.