Introduction

Head-Direct is a small company that specializes in importing Asian Hi-Fi brands to America. Yuin is a Chinese based brand that makes some radical earbuds. They earned their reputation with the old PK line of products, now they have successfully launched their new OK-series earphones. The OK earphones feature a new system that allows you to attach a sound tube in front of the driver effectively turning the earbud into a canalphone.

The OK3’s impedance is only 32 Ohms which is more or less the same as that of all the other earbuds made today. The OK3s will sell for $89 which makes them the cheapest earbud in the OK-lineup by far. It has the exact same design as the other OK-series earphones. Where the OK1s and OK2s are aimed primarily at the audiophile crowd, this more wallet friendly alternative has a much broader appeal. The OK3s can just like the OK2s be run straight out of an iPod or similar DAP’s headphone out. The OK3s feature the same sturdy design as the other OK earphones the only difference is the driver.

The Package

The Yuin OK3s ships with almost the same bundle as its two bigger brothers. The sample I got for review contained only one sound tube, this might not be the case with the final product. The lack of the medium and big sound tubes is definitely a huge con because it will limit your possibilities when you are turning them into canalphones, which can result in poor fit and comfort. The OK3s look just like the other OK-series earphones, the only thing that differentiates them from each other is a small label on the side of the earphone.


The fact that Yuin has decided to ship the OK3s without the other two optional sound tubes is in my opinion a very bad idea. For these earphones to work as in-ears you absolutely have to have all of the customization options otherwise they are worthless for anything else than earbud use.

When it comes to earbud accessories you only get a rubber cover. Instead of having to deal with fragile foam covers you now get an alternative that is just as comfortable and way more durable, plus it is much easier to clean. The new rubber covers should not deteriorate the sound quality noticeably even though they sit right in the path of the sound. During my testing I have become quite fond of the rubber covers since they do not pick up dust from my desk and are pretty easy to wipe clean.

Closer Examination

The OK3s are exactly the same size as the two other earphones in the OK-lineup. The design is very basic. The real innovation behind this new series of earphones from Yuin is the fact that it allows you to mount a sound tube in front of the driver. This little thing allows you to easily convert them into canalphones. Another evolution in the design is the cable, on the old PK1s I have, the cable is made of plastic and is quite flimsy. The new cables are on the other hand made of a soft type of rubber compound which also helps to reduce microphonic noise.

These earbuds feature a rim around the sound hole. This is made from metal and is what facilitates the installation of the canalphone adapters. Of course this means that the earbud is bulkier nearest the ear. The entire body of the earbud is a bit deeper than the old PK-series earbuds, but it is only about 1.5 mm which is too little to be noticed while in use.


The Yuin OK3s have roughly the same back body as the PKs do. There are two small slits, but they are covered from within with what looks to be some kind of plastic, perhaps to balanced the sound. The design of the earphones is anything but flashy, they look plain and boring like most OEM earbuds. There is no doubt about it, these earbuds are specially designed to meet the demands of critical listeners rather than to satisfy the eye.


Like many other earphones on the market the cable enters the body through a short stem. On the OK3s the entry hole is rounded off nicely. The cable on the OK3s looks to be the same as the ones used on the OK1s and OK2s, which is nice. The quality of the cable is really good and seems to cope with microphonics quite well even though it is a heavy and only semi soft type of cable.


The metal rim around the sound hole has a lot of small vents near its periphery. Since it is made from metal you do not have to worry about breaking anything while screwing on the canalphone adapters. These earbuds have a real solid feel to them and are far from as flimsy as the usual generic kind. The hole in front of the driver is covered with a metal grill to prevent stuff from getting onto the driver. The area near the driver has been completely reworked for the OK-series earphones. Now there is a big hole near the center which is covered by the grill and small holes near the edge. It is probably why the sound stage is much bigger on the OKs than it is on the PK-series earphones, that and that the driver has been updated to sound good both in a closed and open environment.


When you look closely you can actually see the driver inside the earphones. These earphones are based on a normal dynamic driver which is standard on so many earbuds. Visually you cannot tell the drivers in the different OK earphones apart, just by looking through the grills.


The logo on the OK3s is pretty small and located on the side of each of the earphones. It is very anonymous so you hardly ever notice it. One of the things that is a bit annoying on the OK-earphones is that Yuin has decided to tone down the left and right markers on the earbuds. This means that it is hard to tell which earbud goes where in a poorly lit room.


The cable on the OK3s is really good it feels solid, handles microphonic noise well, and is quite soft too.


The real disappointment with the Yuin OK3s is that they have decided to ship them with only the short canalphone adapter. This means that you have a very limited amount of options when you are trying to make them fit your ears. Personally I can only make them fit with the long and medium long canalphone adapter and even then I find myself losing the seal often. The difference in length between the medium long and short canalphone adapter is quite big as you can see on the left picture above.


The finish is a bit crude I am afraid, you can see where two pieces of plastic have been put together. The build quality is, however, really good. The earbuds feel rock solid and hard to break under normal circumstances.