Apr 012017
 

I’ve been wanting to try the Duelund DCA20GA tinned-copper tone-wire as a shielded interconnect between my Intact Audio SUT and vintage McIntosh MX110Z tuner-preamplifier for a while now.

DCA20GA tinned-copper tone-wire and Switchcraft 3502AAU RCA’s.

As most of you know, response to the Duelund DCA20GA as interconnects has been extremely positive, and I really like the ones I made up a lot (below).

In fact the DCA20GA interconnects I made haven’t left my primary music system since I installed them between my vintage McIntosh MX110Z tuner-preamplifier and my vintage McIntosh MC30 monaural amplifiers.

Duelund DCA20GA tinned-copper tone-wire interconnects.

In case you haven’t been following the developing Duelund DCA20GA tinned-copper tone-wire story, let me rewind a little bit and give you a quick recap about it.

Duelund DCA16GA tinned-copper tone-wire.

The DCA20GA story:

After Frederik developed the now incredibly popular Duelund DCA16GA tinned-copper tone-wire (above), with its Golden Age inspired oil-soaked & baked cotton dielectric, he decided he wanted to make another version that was optimized for interconnect use.

Frederik settled on a 20-gauge tinned-copper wire, which incidentally has the same count & diameter of  twenty-six strands of 0.15mm diameter tinned-copper conductors that the Belden 8402 uses, but instead of using the Belden 8402’s industrial strength shielding, heaving casing, filler, and synthetic dielectric, Frederik wrapped his DCA20GA tinned-copper conductors in the lithe & natural oil-soaked & baked cotton dielectric that he used in the DCA16GA.

By doing so Frederik has created an exceptional signal wire whose musical & sonic prowess is really turning heads, and the praise is rolling in.

What’s makes it even better is that the Duelund DCA20GA tinned-copper tone-wire is inexpensive, and you can buy it from Parts ConneXion for the very fair price of $6.75 USD per meter.

I asked Chris at Parts ConneXion if he could recommend to me a parts list for making up some shielded Duelund DCA20GA interconnects, and here’s Chris’ recommendation for making up a pair of 1-meter DCA20GA interconnects:

4 meters of Duelund DCA20GA ($6.75 USD/meter)

7 feet of TCBRAID-70765 1/4″ Tinned Copper Braided Sleeving ($1.25 USD/per foot)

6.5 feet of X COTTUBE-72532 OD:11mm, Non-dye Natural Color Cotton Tubing, 100% Cotton ($1.30 USD/per foot)

2 pairs of DUELUND-81404 Duelund RCA Plug, Direct GOLD-Plated ($55.95 USD/pair), or for a budget approach use 2 pairs of Switchcraft 3502AAU RCA’s ($3.99 USD/each).

Kester solder and Switchcraft 3502AAU RCA’s.

The Switchcraft 3502AAU RCA’s are a DIY favorite of mine, being both inexpensive, great sounding, and compatible with narrow vintage input spacing, but they are not built to the same level of quality as the Duelund RCA’s.

0.25 feet of HSHRINK-64093 3/8″ Black – Polyolefin 2:1 Shrink Ratio, Flexible Heat Shrink Tubing ($0.75 USD/per foot)

0.25 feet of HSHRINK-77264 3/8″  Red – Polyolefin 2:1 Shrink Ratio, Flexible Heat Shrink Tubing ($2.56 USD/per foot)

It takes Parts ConneXion approximately 2 hours of labor to put together a pair of shielded interconnects, and if you don’t feel comfortable making up your own, Chris will make up custom pairs for you if you contact him.

DCA20GA shielded interconnect supplies from Parts ConneXion.

I already have plenty of DCA20GA tinned-copper tone-wire and Switchcraft 3502AAU RCA’s, so last week I ordered the rest of the supplies I needed from Parts ConneXion so I could build a pair of shielded DCA20GA interconnects.

They arrived yesterday.

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Step 1. Cut four 1-meter lengths of DCA20GA for a pair of interconnects.

I began my shielded DCA20GA interconnect adventure by cutting four 1-meter lengths of Duelund DCA20GA tinned-copper tone-wire (above).

Step 2. Strip the DCA20GA wire ends for soldering them to the Switchcraft 3502AAU RCA’s.

The next step is to strip the wire ends for soldering them to the Switchcraft 3502AAU RCA’s (above).

Step 3. Solder the DCA20GA wires to the Switchcraft’s pin and ground.

Now, taking two lengths of the Duelund DCA20GA wire, solder (Kester) one length to the pin of the Switchcraft 3502AAU RCA, and the other length to the ground (above).

I like to crimp down the little ground tab onto the wire to secure it in place, then solder it to solder it in place.

Step 4. Attach a bit of red microphone tape to the other end of the wire to identify the DCA20GA soldered to the pin, for reference in the next steps.

Next, attach a bit of tape to the DCA20GA soldered to the pin for reference, so you don’t get the two lengths of DCA20GA confused as you continue through the next steps. I like to use the Peavey color-code microphone tape that you can get on Amazon.

Step 5. I wrapped a little Peavey microphone tape around the ends of the DCA20GA wires to make it easier to thread through the shielding.

I wrapped the ends of the two Duelund DCA20GA wires with a bit of white microphone tape to keep it together while threading it through the tinned-copper shielding.

Then I cut a length of the shielding ..

Step 6. Thread the DCA20GA through the shielding.

… and threaded the two DCA20GA wires through it.

You have to squish the shielding together end-to-end like a Chinese finger trap puzzle to open it up, and then you can ease the DCA20GA wires through the the shielding inch-worm like, as you continue to open up the shielding along its length.

Step 7. crimp down the clamp terminal tab ends on the shielding and wire …

Next slide the shielding under the clamp terminal, then clamp the tabs down onto the shielding & wire (above).

Step 8. Secure the shielding to the clamp terminal with a dab of solder.

I then added a dab of solder to the interface of the clamp terminal and shielding interface to secure it.

Step 9. Putting on the cotton tubing.

In the next step, first tape down the shielding on the unterminated end to keep the frayed ends together so you can thread it through the cotton tubing, then thread it through until you get to the Switchcraft 3502AAU’s plug housing, then tape it down with microphone tape to hold it in place and keep it from fraying in subsequent steps.

As with the shielding, the ‘inch-worm’ approach to moving the interconnect through the cotton tubing works pretty well. It’s a tight fit, so be patient as you work it through!

Then thread the Switchcraft 3502AAU’s handle onto the interconnect. I like to mark the source end handle with a little green microphone tape to identify it.

Step 10. Add the heat shrink tubing.

Next I cut two pieces of the red heat shrink tubing in 2-inch lengths for each end to identify my new interconnect as being for the right channel.

The red heat shrink tubing is just large enough to slide over the Switchcraft 3502AAU’s plug housing, and once I had it in place where I wanted it, I got out a hair dryer and heated it up until it shrank down over the end of the plug housing and cotton tubing.

Step 11. Put the RCA handle in place.

Next I worked the handle over the heat shrink tubing and threaded it into place on the Switchcraft 3502AAU’s plug housing. It’s a tight fit so you have to do a little twisting & pushing to get it over the heat shrink tubing so you can thread it into place.

One end of the right channel interconnect is now done!

Step 12. Thread the handle over the cotton tubing, then trim the cotton tubing to the correct length.

Next I threaded on the second handle, and be sure to get the direction right for threading on to the second Switchcraft 3502AAU’s plug housing that you’ll be soldering on!

Next I trimmed off the excess cotton tubing (above), then slipped the red heat shrink tubing on (below). I the heat shrink tubing in a different order than the first end, just to see if it made it easier to get on, but it didn’t.

Step 13. Note the red tape on the DCA20GA wire that will be soldered to the pin.

Now it’s time to solder on the second plug housing!

Note the red tape on the DCA20GA wire that will be soldered to the pin of the Switchcraft 3502AAU’s plug housing (above).

Step 14. Solder on the second Switchcraft 3502AAU plug housing.

After pulling back the shielding and the cotton tubing, I soldered the DCA20GA wire marked with the red microphone tape to the pin. Then with the second DCA20GA wire I secured it in place by crimping the ground tab down on it, and then soldered it in place.

Step 15. Prepping the termination to make sure the shielding doesn’t ground against the plug housing.

I wanted to build my pair of shielded interconnects with the shielding connected only at the source end, in order preserve the superb sonic & musical character of the Duelund DCA20GA tinned-copper tone-wire as much as possible.

I first pulled back the cotton tubing, then pulled back the shielding so it cleared the back of the plug housing, and then taped the shielding down with microphone tape so that it couldn’t come in contact with the plug housing, to prevent it from grounding to it (above).

Step 16. Putting the cotton tubing and heat shrink tubing in place.

I then pulled the cotton tubing up, positioned the heat shrink tubing in the correct place, and then shrunk it in place with a hair dryer (above).

Then I threaded the handle onto the plug housing, touched up the heat shrink tubing a little with a hair dryer, and the right channel shielded Duelund DCA20GA interconnect is done!

Step 17. A complete right channel shielded Duelund DCA20GA interconnect!

Now I’m going to take a break, and then I’ll build up the left channel shielded Duelund DCA20GA interconnect in the same way, with the exception of black heat shrink tubing to identify it as the left channel.

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A completed pair of shielded Duelund DCA20GA interconnects!

I just finished up my pair of shielded Duelund DCA20GA tinned-copper tone-wire interconnects. Whew, shielded interconnects are fairly labor intensive to build.

Now it’s time to plug them in and hear how they work!

¸¸.•*¨*•♫♪¸¸.•*¨*•♫♪¸¸.•*¨*•♫♪

Shielded DCA20GA interconnects.

I installed my new shielded Duelund DCA20GA tinned-copper tone-wire interconnects between my Auditorium 23 step-up transformer and my vintage McIntosh MX110Z tuner preamplifier for it’s maiden voyage.

The Sumile MC phono cartridge.

The A23 SUT is what I’m using to step-up the Sumile MC phono cartridge, and the combination is sounding mighty fine!

Even with zero run-in time the shielded Duelund DCA20GA interconnects are sounding really, really, nice, which makes me wonder what the fully run0in version will be like.

Got to go, I’ll post more preliminary impressions shortly!

As always, thanks for stopping by, and may the tone be with you!

 Posted by at 7:40 am

  23 Responses to “A Shielded Duelund DCA20GA Interconnect for the Weekend! Updates!”

  1. thanks again for all your work on this new wire. i am anxiously looking forward to the results — as well as how you construct the shielded ICs.

    i have been using unshielded DCA20GA line level ICs for about two months now and could not be happier. i also have been using DCA16GA for speaker cables (4 cores per cable, bi-wired at the loudspeaker) — suffice it to say that these cables are referred to as the “the magic wire” around my house.

    an unrelated question: do you know if Almarro is still making amps? their US dealer network seems to have disintegrated and direct e-mail enquiries not been answered. just wanted to see if you had any news on the company given your review of their A205A MKII amp a number of years back. thanks!!

    • Hi Austin,

      Sounds like you’ve got a good setup going with the Duelund DCA. I’d stick with the unshielded DCA20GA, unless you need it for phono use, where the shielded DCA20GA comes in handy.

      I’m not sure of Almarro’s status, I haven’t been following them of late. I still have my A205A MKI, and it’s a great amp.

      Best,

      Jeff

  2. Great timing! I’ve been curious about how to the shielded DCA20GA would work out. I actually used the part list you provided from Chris the other day to go ahead and place an order. Excited to give this a try. Photos of your assembly process would be very helpful too

    • Howdy Joe,

      I’ve got the shielded DCA20GA interconnects all done and playing music. They’re sounding good, and I’ll be reporting more on them in the near future!

      Cheers,

      Jeff

  3. Really good stuff Jeff, thanks for sharing! Couple of questions if you don’t mind. Did you twist the two lengths of Duelund DCA20GA in the one cable? What is the reasoning in floating on the non source end? Is it better this way when used with SUT to reduce EMI/RFI and or/hum?

    Glad to hear it’s sounding good so far. I look forward to reading your continued impressions.

    • Hi Joe,

      I didn’t twist the DCA20GA for the shielded version I built today.

      The convention in North America is to connect the shield to ground only at the source end. The added benefit of that approach with the DCA20GA is that it keeps the shield out of the signal path, so you hear more purely what makes the DCA20GA so stellar as an interconnect.

      With the Belden 8402 I like the shield connected to ground at both ends, Yazaki-san style, it just sounds better that way to me.

      Both conventions work well with my SUTs, the deciding factor being what works best with each interconnect.

      For example, I tried the Duelund silver wire with the shield connected at both ends, but it didn’t sound all that great that way. As soon as I disconnected the shield from the non-source end, the Duelund silver interconnect immediately improved with the tinned-copper shield out of the signal path.

      All the best!

      Jeff

  4. Hi Jeff,

    you really KILLING US…but I like it!! Please going on with this extraordinary audio trip…!!

    Please advice….From my Pick-up to Pre-Pre Amplifier I must use the shielded version of the DCA20GA IC….

    From my Pre-Pre-Amplifier to Preamplifer ??

    Excellent construction IC’s photo’s…..THANKS!!

    all the best

    john

    • Hi John,

      In my experience, given a particular interconnect, like those built with DCA20GA, the unshielded version will sound better than the shielded version.

      So first I would try DCA20GA interconnects that are unshielded to see if they’ll work without hum in the various points in your system you want to try them.

      If you get hum then you can add the shielding to the offending interconnect. That’s why I built the shielded pair of DCA20GA interconnects, because the position I wanted to use them in always hummed without shielding (SUT to preamp), otherwise I would have built the unshielded ones, which are a lot less effort! 🙂

      Best,

      Jeff

  5. Jeff,

    Do you think the Duelund cable will make for a good power cord? I was thinking of trying that.

    Regards,
    Ian

    • Hi Ian,

      The Duelund DCA series of cables are intended to be used as signal cables like interconnects, speaker cables, speaker & crossover wiring, but not as power cables.

      The Duelund DCA cables are not designed for the high voltages of power cables and you could risk fire, injury, and even death using them in that way.

      Stay safe!

      Best,

      Jeff

      • Thanks!

        Yeah, this is enough to stop me from trying…

        you could risk fire, injury, and even death using them in that way.

        I’m kind of skittish about making up power cords (even using approved cable like Furutech) for this very reason.

        Regards,
        Ian

        • Hi Ian,

          The Duelund DCA series are great signal cables, and my favorite so far, but the DCA harkens back to the very early days of audio when cables – like some of the very early Western Electric examples – didn’t have any plastic in them as a dielectric.

          Plastic or Teflon sheathing over the conductors gives a cable an increased voltage rating, but it also degrades sound quality over a cable like the DCA which uses all natural materials for a dielectric, which in the case of the Duelund is oil-soaked & baked cotton.

          That lovely oil-soaked & baked cotton that makes the DCA sound so stellar is fantastic for speaker cables, interconnects, speaker cable wiring, and the like, but for power cables with their higher voltage requirements, it has the potential to be turned into fuel, so it’s best not to go there.

          Power cables are easy to make and fun to build, but its necessary to make sure the wire you choose is compatible for that use, and there’s lots of good choices.

          All the best!

          Kind regards,

          Jeff

  6. Hi Jeff

    I tried a unshielded balanced cable with one 30 awg tinned copper strand each for the positive, negative and ground legs. The 30 awg tinned copper strands were hit by splitting open a 16 awg Duelund cable which has 26 strands of 30 awg each. In my system, the cable sounds much better than the Belden. The tonal qualities are retained while sounding very alive.

  7. Question. Are you twisting the wires when making up un-shielded IC’s? If so, how much?

    Thanks!

  8. Jeff, thanks a lot for your efforts! For years, I’ve been periodically following your posts, and gained much from your kindly shared insights. And lately, your Duelund’s DCA cable series posts were a revelation (I used to despise all things tin-plated before))). Based on your recommendation, I’ve got a spool of DCA16GA, and was amazed to find that it is as good and in some respects better than my venerable Nordost Heimdall II. I have yet to compare it to my other reference, Kimber 4AG, but I’m sure that Duelund will put up a good fight. I am now thinking about ordering DCA20GA to try and compare it to Audio Note AN-Vx, Kimber KCAG, and various silver Audioquests.
    I have got two suggestions for your further experiments, if you find them worth your time.
    First is trying a combined speaker cable made of single runs of DCA16GA and DCA20GA per phase. May be this combination can preserve individual qualities of each cable, or even improve on them in a synergistic fusion?
    Another thought is putting a Teflon tube over DCA16GA (or DCA12GA) cable just as is, then it will retain all the goodness of its oil-soaked cloth isolation, and also be safe to use as a power cable or high voltage hook-up wire. I used this simple trick for years to employ speaker cables as 220V power cables without a single problem and with much success))).
    Thanks!

    • Hi Vlad,

      Thanks so much for the kind words, I really appreciate it! 🙂

      The Duelund DCA cable series really has been something special, and a lot of fun to experiment with as well!

      Currently I am running a bi-wire arrangement with DCA20GA for the high-frequencies and DCA16GA for the low-frequencies, and that works nicely.

      Just to make sure, are you suggesting a single speaker cable that combines both the DCA16GA & DCA20GA for both low & high-frequencies? That is an interesting idea, and a variation that had not occurred to me.

      A couple of ideas I still want to try are:

      – wiring the low-frequency part of my crossover with DCA20GA
      – building a set of DCA20GA speaker cables
      – rewiring my Westminster’s internally with Duelund DCA

      And now with your suggestion, I’m wondering what a mixed DCA16GA & DCA20GA set of interconnects & speaker cables might sound like?

      The DCA power cable suggestion still makes me a little nervous. It seems like there would still be a risk for fire with high voltages due to the oil-soaked cotton dielectric in contact with the conductors, even with the Teflon tubing around it.

      If you decide to try a power cable with the Duelund DCA let me know how it works. I’m curious about the result, but a little apprehensive about it as Frederik at Duelund cautioned me not to use the DCA for those purposes due to risk of fire with the oil-soaked cotton dielectric.

      Kind regards,

      jeff

  9. Thanks, Jeff!
    I will certainly report on the power cable theme as soon as I get to ordering more of DCA cables from the Parts Connection. Right now I am anxiously waiting for reviews (yours, preferably))) of the DCA12GA, as it may be worth getting as well. I live in Russia, and the postal expenses from around the globe may be a considerate part of the overall order value (so I try to wait and combine my needs and orders). I myself would very much like to try running DCA16GA and DCA20GA in parallel (or other combinations including DCA12GA), but I’m not sure when I get the chance.
    Many cable manufacturers run insulated wires of different gauges and metallurgy inside a single cable to combine their individual sonic and electrical properties – and most often used by audiophiles without bi-wiring, and even per single loudspeaker phase. Examples would include cables from Cardass, Audioquest and many others. Even Kimber PSB / TCSS (base wire in PBJ, 4TC, 8TC, 12TC) uses MultiStrand technology and consists of a bunch of wires of different sizes (not sure if they are enameled or not). With the DCA series, it may or may not be beneficial – only experiment will show.
    As for the power cables safety, a risk of fire usually results from using very low AWG wires with higher-power electronics and thus overheating, or from bad electrical connections. Based on personal experience, I would subjectively rate DCA16 (short runs up to 3m) as good for anything up to 600W for 220-240VAC power, and about 350W for 100-120VAC (with DCA12GA probably twice the values). The risky part is the need for better electrical insulation (solved by placing teflon tubes over the each wire inside the power cable), and connections that may overheat due to bad contact or oxidation of the contact surfaces. That is easily solved by soldering wires to connectors after screwing them together, and using plugs and sockets with non-oxidation plating like gold, rhodium, etc. (and even those require periodical cleanups with alcohol or GAIG Deoxit / ProGold). Silver oxides don’t decrease conductivity, but I wouldn’t expect silver and tin platings to mate well sonically. As for power cables made from speaker cables, I had great results with VanDenHul CS122, Kimber 4TC and 8TC, Audioquest Indigo, Nordost RedDawn, and non-audio Jewelry bulk wires made of soft annealed 99,9% pure silver. Interconnects Kimber KCAG and PBJ make great power cables for low powered electronics like DACs, players and preamps. On all of those I used copper mesh shielding grounded at one end (connected to the electronics), poly mesh braid, and multiple ferrite rings united with a piece of heat shrink over them.

    Regards,
    Vlad

    • Hi Vlad,

      Thanks for your comments on building power cords! There’s more to consider with power cords from a safety standpoint with the Duelund oil-soaked and baked cotton insulation than with interconnects or speaker cables, so I feel a little apprehensive about recommending it to people. Keep me posted on your experiments though, I’m interested in your results!

      Kind regards,

      Jeff

  10. HI Jeff I took your advice and amended the cable build this time using the screening material and built to your
    excellent tutorial, and hey presto, the dreaded Hum has now gone. Using a 300b Power amp was a definite no no with unscreened interconnects and so the screening did the job. I also made up some as you did for use between my Pre amp and my Hashimoto HM-7 SUT and again with great results in much reduced hum. The pair between my DAC and Pre have no screening.
    Initial findings are very positive and help to offer great music.
    My wife initially commented that the Bass extension was lost a bit? ( i didn’t find this!) but she insisted the Bass extension stopped extending as far as it did with the previous cables. I explained the Cables had to bed in and would open up over time… she looked at me like I had just said Aliens had landed on the Lawn and raised her eye brows (not sure she believed me!!!!….
    Best Regards
    Adam

    • Hi Adam,

      I’m glad you’ve banished the dreaded hum! It’s amazing what a little … or a lot … of time can do for performance. Some components & cables, like fine wines, have to age and then ‘breathe’ for a while to get the best from them – it’s worth the wait!

      It can sound crazy to those who are not familiar with audio, but pour her a glass of good wine, let it breathe for a while, then explain the analogy – all will be come clear!

      Kind regards,

      Jeff

  11. I have been using the DCA20GA shielded to and from a SUT and the DCA20GA unshielded to my amp for the past 3 weeks or so. First off, I’m not all the experienced with building cables, however, I found Jeff’s blogs on the topic invaluable. I wouldn’t of even attempted the project with out his tutorials and inspiration. I’m so glad I gave it a shot because the sonic benefit has been quite noticeable. I was worried about adding more “noise” with the cables but it’s been completely the opposite. My vinyl playback has never been “quieter” then it is now! What a relief. I’m hearing such a natural, beautiful tone on vocals and instruments with the Duelend cable. A much more coherent sound with the right amount of air and staging too. Thanks for the musings on the Duelund wire Jeff… a worthy audio adventure!

    • Thanks for the report, Joe, that’s awesome! Keep me posted on developments, and thanks for the kind words!

      Cheers,

      Jeff

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