The Package

Right now the package for the OK1s is not finalized. The bundle I received is the same as that of the final product. You get a lot of different stuff with the OK1s. Besides the earphones you get three earbud to canalphone adapters, three single flange tips, one double flange, a rubber earbud cover, and last but not least a 1/8" to 1/4" adapter.

The Yuin OK1s are a pair of very high impedance earbuds, a normal earbud has an impedance of around 16 Ohms. The Yuin's impedance is a mighty 150 Ohms which makes them considerably harder to drive. This causes quite a bit of trouble because most normal DAPs do not have a good enough internal amplifier to drive them anywhere near their true potential. If you have a DAP with a good and powerful headphone out you can get them to sound fairly good. In order to truly let them shine you need to get yourself a decent headphone amp. This definitely makes the Yuin OK1s a very unique niche product. By themselves they are portable, but if you want optimal performance you will have to carry around a small headphone amp, the latter is of course more of a hassle. If you like I appreciate good sound you will definitely want to have a headphone rig that includes a good portable headphone amplifier. The Yuin OK1 earbuds / earphones are roughly the same size as a pair of normal earbuds. That being said they are quite big for a pair of in-ears.

Closer Examination

The earphones look quite like the older PK-series earphones from Yuin. As far as I can tell there are two noteworthy cosmetic updates on the OK-series earbuds. The first being the metal ring around the earbuds sound hole, the other is the cable which has been switched from a plastic type cable to the soft rubbery kind. Both are of course welcome additions to the design, definitely two tweaks that gives them an edge compared to the older Yuin PK1s.


When looking at the earphones right from the side you can clearly see the new metal rim. Otherwise they look quite ordinary. The build quality is good, however, the finish is a bit brutal. You can see the place where plastic pieces have been bonded together. The design withstands physical abuse quite nicely without giving way to pressure.

The small logos on the side of the earphones will probably wear off over time since it is just a small transfer. The same logos on my old Yuin PK1s are beginning to rub off a bit now, but they are also over a year old and have been used a lot.


The old Yuin earbuds had a plastic cover that sat in front of the driver. The new OK1s have a metal grill and quite a few holes in the periphery of the driver. According to the manufacturer all of the internals of the earbuds have been completely reworked from the ground up in order to make it sound good in canalphone mode. This did unexpectedly make them better sounding earbuds as well.


With every pair of Yuin OK-series earphones you get a lot of tips. You get three sets of single flange tips that you use when you have converted them to in-ear use. What surprised me a bit was that Yuin has decided to go with a new type of rubber cover instead of the usual foam covers. This is a first for me, all the other earbuds I have all came with the standard foam covers.


The new rubber covers extend further over the back of the earbud than normal foam ones do. I found them to aid comfort a bit without affecting the sound quality much.


One of the special features of the Yuin OK1s is that they can be used both as regular earbuds and as pseudo in-ears. The in-ear functionality is achieved by screwing on an adapter on to the earbud. The adapter comes in three different lengths to make it easier for one to get a decent fit. The rim on the earbuds is made from metal so that the adapters can be screwed on and off without damaging the earbuds.


Each of the two big adapters has a filter on the end of the tip to prevent earwax and oil to enter the earphone. The smallest of the three adapters does not have this. I guess it is not all that important for the functionality of the earphone.


The driver of the Yuin OK1s is clearly visible through the metal grill. The driver has what looks to be a parabolic shaped surface. Also visible on the picture above are the small vents near the edge of the earbuds.


Above you can see a small comparison of the three adapters. The size difference between the small and the medium is huge, however, the difference between medium and large is microscopic.


All of the adapters have a small indent or grove nearest to the ear. In order to install a tip on it you just push it on and it locks in place just like with any other in-ear I have ever tried.


The mini-jack on the OK1s is fairly durable and slim looking. It is probably iPhone compatible, but I cannot phantom who would want to run these power demanding earbuds straight out of such a device.