As a member of the Head-Fi discussion board community since January 2003, it has been wonderful to be part of the flourishing personal audio community. Cables like the Estron Linum Balanced two-pin 2.5mm TRRS (€145, or around $160) as reviewed here are what's fresh and new, yet is something more of an evolution in my eyes. My love of personal audio dates back decades before that as my first experience with headphones was before first grade school. The closed back headphones were by Koss, 'natch, and was a revelation. I've been hooked ever since! During my teens to early 20s sold electronics and became manager in short time of a big box store. After that gig did a stint with a high-end personal audio specialty store. It wasn't called 'high-end' back then, yet the top gear was an Aiwa stereo cassette player that also recorded (in stereo!) and the Sony D-10 (or was it the D25?) at that time. Hey, it was the 1980's in Miami and was a musician so some of my memories at that time might be a bit, ummm, shall we say 'hazy'.
So as the years passed have watched the whole personal audio ebb and flow. If someone would have told me decades ago it would be where we are today I would not have been surprised. There is something incredibly special about being able to tune out the outside noise and turn up the music. With our lives becoming ever-more chaotic in so many ways, plus the unwanted noise during constant airplane travel many of us deal with, our ears are bombarded by external sounds (noise) all the time. Good thing we now have custom in-ear monitors, as they highly reduce those harmful and unwanted external noises while also ensuring a nearly silent sanctuary for our ears to be basked within the glory of our tunes.
So what comes next after custom in-ears within the now properly-titled high-end personal audio? Cables! Just as the high fidelity home audio market discovered that cables make a difference, the personal audio guys are now playing catch up. My previous world premiere review of the Double Helix Cables' Symbiote Fusion 4 and Symbiote SP 8 CIEM cables with 3D printed rose gold highlights brought my beloved Noble Kaiser 10 to new heights in their ability to provide hour after hour of musical bliss. Ok, let's admit it right here and now that the Double Helix cables are not what you'd call small and discrete in appearance. Due to their size, they can be a bit challenging, especially if you're trying to be a bit discrete. Then again the Double Helix cables boldly show the world you deeply care about getting the very best, or at a minimum add to your cool vibe of diggin' tunes. But what if, just if, you want to be a bit more laid back cadge (short for casual, 'natch). Maybe you want your CIEMs to hide in the 'shadows' or, dare we say, desire a cable that sounds different? Perhaps you're a stage musician and thus want to have your precious hearing-saving CIEMs hide in the shadows on camera.
You Can Never Be Too Thin Or Too Tall
Their cable designs are done in Denmark, with production and office facilities in Denmark, China and Vietnam. They work hand-in-hand with their customers to produce products as requested. The more requests, the higher the probability they'll design and sell a new offering to the masses versus one-off designs. While the Linum two-pin balanced cable only comes with the very small 2.5mm male TRRS connector, if there's enough demand they might offer a larger 3.5mm size male connector. Advantages of this are easier to source TRRS to TRS adapters and of course it is more common to go from a larger to smaller size than a small connector to a larger one. Also, a 3.5mm would be sturdier to then go to 2.5 than going from 2.5 to 3.5mm. The 2.5mm version perfectly fits Astell&Kern's PMP balanced output and so this review was done with the outstanding Astell&Kern AK240.
Estron, by the way, are certified ISO 9001 and are REACH and RoHS compliant. So basically they adhere to top professional standards. The Linum cables are extremely thin and flexible. When I say thin, we're talkin' a mere 0.9 mm! Yup, less than a single mm and so are virtually invisible to the eye of others when you're wearing them. The cable design “is typically Danish which is famous for combining simplicity and functionalism” says Estron. As for weight, the entire assembly including connectors is 2.7 grams (~0.095 ounces) and the Music product is their lightest model. Estron's wire for the Linum two-pin balanced 2.5mm TRRS as reviewed here uses six Litz conductors made up of seven individual strands. Each strand is silver plated copper, whilst an enamel coating keeps each wire from direct electrical contact with the other until it reaches the end connectors.
Ok, so now you might be thinking with a cable so very thin, it must be easy to break. Ah, you'd be wrong! With a pull strength 60N (13 lbs.), the wire itself combined with aramid fibers during assembly ensures they are very durable. The Linum outer jacket is made from TPA, which is skin-friendly and UV stabilized; and thus it will not turn yellow if exposed to sunlight. Another factor you might be thinking is that with a cable so thin, well, they might easily get tangled. Special memory wire does not tangle easily and so far they are about 85% right. Let's face it, all cables of length will tangle to some extent, yet it is in how easy it is to untangle them that makes a big difference. During my review this cable tangled only a very few times, yet were easy enough to undo the mess I made… and I can easily make a mess of headphones cables!
The Sound Of Small
With the JH Audio 13 the results were the same and they brought their performance up a notch. Everything sounded a bit more natural, yet still quite accurate. Bass, like with the Ultimate Ears UE18 pro, was extended a bit further yet retained accuracy without ever getting bloated. The highs were also a touch smoother a slightly more extended. So basically the results were the same with the JH Audio 13 as they were with the UE 18 Pro. If you're still using a stock cable on either of these CEIMs, you really should try the Estron Linum Balanced two-pin 2.5mm TRRS custom cable.
Overall, there were big dynamics revealed as there were added microdynamic shading, yet there is one kinda strange thing going on. The initial attach and brief sustain for the first fractions of a second were great, then there was a faster drop-off and then leveling off until notes disappeared. It is as if something very briefly 'in the middle' of the dynamic structure dropped off a bit faster than usual. Thus smooth decays into a black background were more like initial reduction in volume level, then brief and fast drop-off followed by smooth final disappearance. Had hoped one of my 2.5mm to 3.5mm adapters I got in Singapore would have worked so I could test the cable with other digital audio players, yet something was not quite right and thus it did not work correctly. So am a bit perplexed where to go from here, as I can only use this cable with the AK240 (and original AK120 as reviewed here) at this time.
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