Closer Examination

Ah, now we know why a tool to take the cable off the IEMs is included. Ikko has gone from the 2-pin connector cable on the OH10 to MMCX. This is a locking connector you need to be careful with during installation and removal, and certainly don't tug on the cable to remove it lest you rip the wiring off the connector. The cable itself is a departure from the OH10 cable as it no longer uses a 90° angled housing for the 3.5 mm TRS plug. As the material composition goes, it is an upgraded cable and was an optional $59 extra for the OH10, so I am glad to see it included in the box this time around. Ikko says the cable uses a 127 µm diameter high purity single crystal copper core, and promises better resolution over the average stock cable. The copper core also has a thick silver plating, which supposedly makes for a "more transparent ultra-high frequency presentation." What it comes down to is that this is a low-impedance cable, and that's really the end of it as far as I am concerned. There is still the weaved section throughout that splits into two past the splitter, and black insulation to where it goes into the connector itself. This is a nice-looking, thin cable, which is easier to carry around in a case too.


We now get to the star of the show, or should I say gems? I am glad to have both color options to better compare and contrast the two, and I have to say I really like how they look. Gone is the glossy finish from the OH10 in favor of a smoother shell, and both colors offer something different to where I keep flipping between which one is my favorite.


At ~7 g each, these are slightly lighter than the average IEM buds. This is a big drop from the behemoth that was the OH10 at nearly 16 g each, and all of this has to do with the shell. Instead of a full copper and titanium shell, the Ikko OH1S uses aircraft-grade aluminium alloy layers with a medical-grade resin in between. The exterior surface area might as well be called a face plate and retains the chiseled texture that worked better on the OH10 than here, though it works well with the gem moniker of the OH1S. The gray sample is subtler, with the blue more shiny in reflecting light off the surface. The gray set has a purple resin layer, which makes for really nice contrast, whereas the blue set goes for a lighter shade of blue for the resin. The three layers of the shell (aluminium alloy-resin-aluminium alloy) are also curved softly to go with the rounded, ergonomic-friendly shell design.


The MMCX connector is inset on the side to mate with the cable seen above, and we see vents on the side that will help with cooling, but not to where sound isolation will be compromised. There is a tiny Ikko logo on another side too, with an "L" or "R" marking underneath to tell you which ear these go into. Note that the purple resin might as well be opaque, but the lighter blue resin is translucent to where you get a peek at the hardware inside. The other thing of interest is the nozzle itself, which has notches to retain the ear tips, but more interesting is the use of an oval-shaped design, which is why we had the oval-shaped silicone tips from before. The nozzle is 5.7 mm in the larger dimension, so you need ear tips with a ~6 mm core—good luck finding third-party oval tips. Ikko says this is a deliberate choice to better fit the human ear canal, and we will talk more about this on the next page. A mesh filter over the nozzle prevents contaminants from going through, and it is replaceable, so I appreciate the inclusion of two spare inserts in the box.


Fitting the individual components together only takes a couple of minutes, beginning with the ear tips on the earbuds before putting the connectors into the earbuds themselves. The foam tips are a bit finicky on either end, and the photos above were taken while these were getting back to shape from having been depressed during their installation, but these provide a better fit to where it is worth the effort if the silicone set is uncomfortable. Seen above are two different sizes of each used type, and just how oval a shape the larger silicone tips adopt is still hilarious to me. A 90° angled adapter for the 3.5 mm plug would have been nice, but this is not a dealbreaker by any means. I know there are many who prefer to use IEMs throughout, but I like to use over-ear headphones when sitting down and IEMs/TWS earbuds on the go. In the absence of other options at this time, I hence chose to use them primarily with my trusty FiiO E17.


Since the Ikko OH1S sells alongside the OH10 at the same price, I had to do a visual comparison. Look at how much smaller the OH1S is, which no doubt also contributes to the lower mass compared to the OH10. The smaller form factor is also complemented by a rounder design compared to the more triangular one of the OH10. We will check on how this affects the fit with those oval silicone tips on the next page.