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The UBYTE-2 Speaker Cable

[Italian version]

Almost half a year ago, following on from some research into Speaker-Cables, various Articles, conversations with a lot of people on the Internet and finally a number of Usenet posts from Jon M. Risch, I made the first incarnation of the UBYTE Speaker-Cable. The UBYTE Moniker was coined by Pat from Analog Research and stands for "Usually Beats Your Terrible Engineering".

This Cable is similar to the Cross-Connected Belden 89259 75 Ohm Coax Cable Mr. Risch recommends so highly. However, I decided not to use the Belden 89259 as it a bit hard to obtain. In addition all the Conductors in the Belden Cable are stranded. In my experience this is not such a good Idea.

The Cable used for Speakers in my system at this time was a "double run" of Category 5 network-cable. Both lengths where twisted together, based on suggestion from fellow Joe-netters. (The Joe-Net is the Soundpractices E-Mail list, mostly concerned with Single-ended Valve Amplifiers of minuscule output but often a lot of useful info is on there too.)

This Cable had replaced the 12-Gauge Mega-Cable sold by Tandy/Radioshack (not a bad cable for the Price by the way) resulting in major Improvements for clarity and transparency. I still recommend the Category 5 Network Cable as the cheapest decent Speakercable and for many the performance of a pair of these Cables may very well be all they ever want or need.

However, just like any Audiophilia Nervosa Sufferer, for me there is no such thing as good enough....

The original UBYTE was different from the Design proposed by Mr. Risch in that the Cable used had a solid (not stranded) Center Conductor and a Copper-Foil Shield with a thin Braid over the Copper. Unfortunately, the Jacket Material is PVC, not so good, but in this application just about tolerable. This Cable is sold under the CT100 and FT100 Designations respectively by RS-Components and Maplin Electronics. It is covered in the DIY Cables Resource Guide.

This Cable was very good and had me really excited. It stayed in the System for a good while, but I finally decided to address the two things I was unhappy about in the original UBYTE Speakercable. I was unhappy about the PVC and (much more) about the outer Shield Braid used on this Cable as this introduced a certain amount of multi-stranding to the Cable.

In case you want to make a VERY GOOD Speaker-Cable, below you will find detailed instructions how to make such a Cable. As for the Electrical parameters of the Cable, I have measured (for a 5.5m long Cable) less than 0.2 Ohm Loop Resistance (including the Spade-Connectors fitted) and a Capacitance of about 800 pF. These values are similar to those for the Kimber 4TC Cable.

Where the UBYTE excels is low Inductance. For the Cable as constructed there is less than 1uH overall Loop Inductance. Compared to the Cat 5 Cable Twisted Pair the Inductance is reduced by the factor 3 to 5, compared to Kimber 4TC by still more than 2. Another Plus-point is the fact that this Cable combines two of the most individual (and good) sounding approaches to Speaker-Cables.

Cables using a moderately thick solid copper conductor (like the DNM/Reson Speaker-Cable) have a tendency to be extremely good in the Midrange and with human Voices. The Frequency Extremes are treated less well. On the Other hand, Copper-Foil Cables (like Goertz Alpha Core) haveexcellent Performance at the Frequency extremes but are a Load many Amplifiers simply cannot drive.

Combining both approaches gives an excellent Balance between Midrange Detail and Naturalness on one hand and good extension on the Frequency extremes. I believe that this Cable has to be heard. It was for my System a "Quantum-Leap" similar to the one the X-Cables provided for the Interconnects.

The Construction of the Common Carpet Python

Your mission, should you accept it is to go down to the Electronic DIY Shop and buy all ingredients and assemble a pair of UBYTE-2 Speaker-cables suited to your own installation and listen to them.

Accepting the challenge? Read on. To wet your appetite, here a picture of the completed common carpet python in its natural habitat.

[UBYTE-2 Cable - click for full size]

Let's shop

Get "Low Loss Satellite" Cable. This is highly important as only the right base cable makes for the magical U-BYTE Cable. This Cable uses a solid copper center conductor (stay away from copper-plated Aluminum or Steel but take silver plated solid copper where offered) of about 1mm Diameter.

It also has a full copper foil shield (not metalised film or aluminum - never use these) with a relatively sparse plain copper braid over the Copper Foil. If it does not have the copper foil, it's NDFG (could be read No Darn Flipping Good) for our purposes.

The Cable in question will have either foamed Teflon or Air-cell polyethylene Insulation (foamed Teflon should be better). The whole Diameter per cable will be 5-7mm. Buy twice the length needed (for example, for two 5m runs of speaker cable buy 20m of the Cable....). The cost should be around 1 - 1.5 USD per Meter.

Also buy heatshrink sleeving with a large enough diameter to accommodate two of the Satellite Cables side by side. It has to be long enough to run the full length (for the example above 10m Heatshrink with about 20mm shrunken diameter). I personally used white heatshrink. I also found once I got home that the 10m Reel I had bought had only 8m on it... Hence in the Photo above there a few parts of the cable not fully covered. I think it actually makes it look cooler....

You will also need white and red colorcoded Heatshrink for about 5mm Diameter in shrunken condition. The Heatshrink should be at least of the Polyolefin variety but Kynar or Kyp Heatshrink is a lot better. You will need exactly the same length as the Cable you bought (for the Example 20m).

Buy four sets of your favorite termination. I prefer Radioshack/Tandy goldplated Spades (code # 316-A); they are copper and cheap. Get the ones for 16 Gauge Cable.

You will also need about two spools each of black and two spools of red 30 Gauge Wirewrap Wire. Another ingredient (though by no means essential, but it makes the Cable look better) are four small long Rectangular Boxes (plastic or metal) with about 30 mm X 30 mm crossection and about 100mm length.

See to pick up some PTFE Tape (Plumbers Tape). About 5m will be plenty.

Now go to the usual place to obtain copious quantities of snakeoil and fairydust (buy a little extra....). Bat-Ear Powder is also highly recommended in this application.

Having gotten all these goodies safely home prepare a source of heat (Heatgun will work well), soldering Iron, Kester 60/38/1/1 SN/PB/AG/CU Solder (Call it Wondersolder, sprinkle Fairydust and snakeoil on it or don't bother) and plenty of space (which we all know is the final frontier).

Let's twist again, like we did last summer...

Got that? Fine!

The first step is to make flexible Leadouts for the Cable. These should start with 36 strands, 35cm long each, of the Wirewrap Wire. You could just pull them trough a suitable size Heatshrink sleeving. Better, you can make a multiple twist "braid".

For this take six strands of the Wirewrap wire and twist them between your fingers. For the red Wire twist clockwise, for the black, anti-clockwise. Once you have made six sets each of the six twisted wires, twist these six sets together to make a very flexible, low inductance and decent looking leadout wire. Again twist the red stuff clockwise and the black anti-clockwise.

Put the Termination you decided to use (WBT Banana Plugs, Radioshack Spades or whatever takes your fancy) onto one end of the leadout-wire. Indeed, I have found that stripping the insulation off from each wire before braiding them and twisting just these ends together tightly allows for much easier twisting. Putting all six finished Mini-Cables into the Plug, Spade or whatever you use before twisting the six sets together makes this job again a lot easier. Trim the other end of so it looks neat and all wires have the same length.

You could of course buy short length of Cardas OEM Wire (in 15 Gauge or more) or any other Cable that avoids multistranded wire. In the End, one way or the other you should now have four red and four black leadout-wires with some form of termination on the end of the wire. I always crimp my Radioshack Spades onto the Cable using extreme pressure to achieve a "coldweld".

Finally remove the insulation from all the single wires on the other side of the cable (the un-terminated one). You will have to untwist for a few cm and retwist it after removing the insulation for that.

More than an arm up these sleeves

Now take for every length Cable needed two sets of the Coax Cable (continuing with our example - four 5m Ends). Please mark the Ends for the Direction how the Cable came off the Reel. I have not found Cables to behave directional, but one never knows. It certainly will not do any harm.

The next step is to take each End of the cable and a sharp Stanley knife and to cut through and remove both the PVC Jacket and the copper Braid. To prevent the Copper Foil of the shield from tarnishing it is best to wear gloves.

Please be careful at this step. It is easy to tear the foil is the Cable is bend to much rendering the whole length unusable.

After stripping off the "Acne" of the Braid and jacket, solder a >5m Long Draw-wire (solid core 1mm mainscable works for me) to the Cable. I recommend to solder the draw-wire to two of the Cables on the start side of the Reel (remember we marked them?) and the other two to the end side of the reel. Use the red Heatshrink on the cable having the draw-wire on the start-side and the white heatshrink on the other two.

Re-sleeve the cable in the smaller Diameter Heatshrink (probably 9.4mm unshrunk). The Draw-wire helps immensely pulling the Cable through the Heatshrink. Shrink the heatshrink carefully and step-by step (do not coil the cable up and put it in the Oven!!!).

As a result, we are now left with four lengths of Cable consisting of a solid copper Center, an airspaced polyethylene(or Teflon) insulator, a solid copper-foil shield covered tightly by Polyolefin (or Kynar/Kyp) Heatshrink. Two lengths will white and two will be red. There will still be a >5m Long draw-wire be soldered to each.

Now Take one of the length each in white and red and lay them out in parallel on the Floor, so that now both draw-wires are also parallel. Get the large diameter heatshrink over them taking care to leave about 15cm at each end exposed. Again, the Draw-wires help a lot. Shrink the heatshrink tight. You could twist the cables around each other; but noting the comparable fragility of the Copper-foil, I decided against it.

Fill the whole assembly with some snakeoil while we are there. We now have two raw ends of the "Common Carpet Python", waiting to be terminated with our leadout wires.

Terminator X - terminating

Finally time to put all these little and large bit's together to get a working cable. Zen being what it is (and when making complex DIY Cables like this one a lot of Zen is needed together with a few beers....), we should concentrate on the process and not on the result, but in the End, no matter how nice it looks; we are in this for the MUSIC.

Get one end of one Cable. Take off about 5cm of one of the two Cables. It does not matter of which of the two as long as you retain consistency throughout both halves of the Stereo-pair.

Drill suitable holes into the rectangular Boxes you bought, so that the two Coax Cables and their overall Jacket can go into on one end and the flexible Leadouts in the other. If you use metal Boxes, make sure to use rubber grommets to prevent the Metal corners from cutting through the Cables insulation.

Strip 2.5 cm of the jacket, copperfoil and inner insulator off the shorter Cable. Remove another 2.5cm of the outer insulator. Cut back the copper foil (I used a small Scissors) by half of this distance. Your assembly should now look like this....

[UBYTE-2 Cable assembly step 1 - click for full size]

Now repeat the same process for the second Coax Cable, but here Strip the center conductor bare for 5cm not 2.5cm. The result of this should look like this....

[UBYTE-2 Cable assembly step 2 - click for full size]

The Center-conductor for the first coax should be exposed for 2.5cm; for the second coax 5cm. Take this End of the Cable and slip the (open) box prepared over it. Insert also the two Leadouts, so that the black one is near the white sleeved coax and the red one is near the red sleeved coax.

Now take the exposed center conductor of the first coax and bend it at right angle over to the other coax in the cable. Wrap it halfway around the copperfoil and then put the exposed wires of the appropriate leadout wire (in our case a black one) under the centerconductor and above the copperfoil. Spread the individual wires out so that there is plenty of intimate metal-to metal contact between foil and leadout wire. Finish wrapping the center-conductor tightly around the copperfoil. Then solder the area with the leadout wire quickly and with plenty of flux and heat.

BE QUICK OR YOU MELT DOWN THE INNER INSULATOR AND CAUSE A SHORT!!!! Such a shorted cable may destroy your amplifier!

This is what you should end up with....

[UBYTE-2 Cable assembly step 3 - click for full size]

Now bend the other Center Conductor across and down (now you know why it's 5cm long) and repeat the process form above for this side. The endresult should look like this....

[UBYTE-2 Cable assembly step 4 - click for full size]

Of course all of this should be inside the small metal or plastic box. In certain cases the Boxes in which we fitted the Junctions, can be used to hold "mystical, magical, snakeoil and fairydust treated" U-BYTE Load Stabilisation, RFI rejecting networks (we talk about that in another article in detail).

With these Networks in place these cables can be used with amplifiers from Linn, NAIM and NVA (and all others that eschew the use of load stabilisation networks and thus carry serious health-warnings about which cables to use with them and which not). They also help with badly designed speakers that have no compensation for the tweeters Inductance.

Now take the PTFE Tape and wrap all of these connections and exposed copper up (like the mummy's of old...). Wrap tight and then sort-of press the layers down. This makes a pretty airtight seal, preventing the junctions from oxidising.

Use Cable Ties to provide a strain-relief for both the flexible Leadouts and the double coax. Complete the other end of the Cable; this time taking care to cut the 5cm of the other coax (so if started as shown to chop the red cable short, now take the white....) and then complete Cable number two.

Given that all of this was a huge load of work, put everything aside and have a glass of your favorite liquid or two. The next Day measure the Cable to make sure you did not "fit" any shorts.

Now apply further copious amounts of snakeoil and fairydust before you drop the Cable into your system instead of your multikilobuck stuff (or the cheap Ratshack Monsterwire).

Put on music. The cable may get better with use, but I hope you hear what I heard when I put it my system immediately.

That's it for today. Have fun. Enjoy the Music.

PS. If anyone uses Speakers without HF Impedance Correction, get an 6.2 Ohm Carbon Composite Resistor (2Watt - non inductive) and a 0.47-1uF Siemens stacked Film Capacitor (or equivalent) and connect these across the cables at the Speaker-end.

If you use NAIM Amp's (or others that warn you about using highish capacitance cables) make three turns around a 6mm Core (say a piece of a cheap plastic Biro) in each of two leadout wires at the Amplifier side, and connect a 10 Ohm, 0.1uF Zobel across the cable at either side of the small Inductors (making a symmetric PI Filter in essence).

Now we made a Network Cable, which in addition is directional. This of course calls for more fairy dust and Snakeoil application.....

Ps. Ps, I hope you do not take the references to fairydust and snakeoil literal. These are costly substances and are not needed in the DIY version of the Cables. The Commercial Version of the Cable will need lots of it of course..... :-)

© Copyright 1998 Thorsten Loesch

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