We've all been in that position when we want to plug our iPod / MP3 player / PCDP or other portable device into our home stereo. Today's smartphones let you stream music from your computer, radio stations and services like Pandora straight through the web; it's tough to disregard all this utility and flexibility when compared to something like the single disc CD player plugged into your rig. In today's blog, I will be constructing a simple but excellent sounding mini to RCA cable that can bring all those modern features to your home amplifier.
A mini connector, also known as a 1/8" or 3.5mm TRS (Tip, Ring, Sleeve) is the de facto standard for portable headphone connections and has been around since the mid 20th century, being used with earpieces on transistor radios. The original 1/4" version dates all the way back to 1878 (!) and was used for telephone switchboards. This mini connector is connected to a braid of wires that then convert to a left and right RCA connection. RCA connectors were designed in the 1940s to connect phonographs to amplifiers. It's a mild curiosity why the industry is still using such an age-old connector designs. More modern and esoteric designs like the iBasso Toucan and Ray Samuels SR-71B make use of unique balanced connectors such as the 6 pin Hirose and 4 pin Protector, designs that will likely never make it to mainstream audio equipment, but it's nice to see the designers offering these options.
I'll be starting this mini to RCA cable by trimming four strands of equally long wire in preparation for braiding. I'm choosing silver plated copper in Teflon as it has nice sonic properties and is relatively inexpensive compared to boutique audio wire. Silver plated copper (SPC, as I call it) in Teflon is offered by companies such as Belden and can sometimes be found as military surplus (mil-spec). Not all SPC is created equal, and you'll want to be sure you're getting silver plated copper and not tin plated copper. SPC is discussed in more detail in my post describing custom made
SPC Speaker Cables.
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| Four Strands of Silver Plated Copper in Teflon |
Once the wire is laid out, the strands are braided into a
formation of four wires so that the cable maintains the same EMI/RFI rejecting geometry all the way across the length of the cable. Do note that one needs to cut the wire a little longer than necessary as a few inches of length will be lost in the braiding process.
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| A nice, tight litz braid leading to two twisted pairs |
Once the braiding is complete, the wire is fed into a sleeve of soft black nylon multifilament. This gives the finished product an attractive look. Nylon sleeving can also help negate microphonics in headphone cables. At the Y-split, I melt the multifilament together to ensure that it does not separate when pulled or tugged. A Y-split is also added with multiple layers of adhesive heatshrink. You can see an another take on a Y-split in my custom AKG K1000 cable post.
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| The sleeved cable with Y-Split |
RCA connectors will now be added to the two twisted pairs of wires. Some sleek-looking chrome plated RCAs were selected for this particular cable, but I will typically use Canare F-09 or Switchcraft 3502 series gold plated RCAs as I have found them both to be well-built and reasonably priced.
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| Chrome RCAs attached |
Next comes the mini to mini connector. I almost exclusively use Switchcraft 35HD series connectors. They are made in the USA, sturdy, and not too large. The Canare F-12 minis are nicely made, but the barrel is very large compared to other connectors. If one needs a plug that's physically smaller than the Switchcraft, the Neutrik NYS231 will fit the bill. It's about a quarter of the price of the Switchcraft but doesn't seem quite as solid in my humble opinion.
The Switchcraft connector has a small piece of metal on the ground connection that I personally don't use, so it's trimmed off with metal snips. Once the soldering connections are made, all connectors are tested for continuity and shorts using a multimeter. They are then isolated with heatshrink as an added precaution to prevent shorting. The crimp on the ground connection holds both the wire and sleeving in place and prevents strain on the soldered connections.
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| Switchcraft mini connector attached |
As an added strain relief, a piece of 1/4" polyolefin black heatshrink secures the sleeve to the ground crimp.
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| Added heatshrink as a strain relief |
The barrel is now screwed onto the Switchcraft mini connector and that completes the mini to RCA cable.
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| The finished mini to RCA cable |
I hope you enjoyed this step-by-step walk-through. If you are interested in purchasing a custom, hand made mini to RCA cable, they are more affordable than you think, and are available from Zynsonix.com
