Diaphragm: 16 mm., mylar
Nominal impedance: 32-ohm
Nominal power input: 2 mW
Maximum power input: 5 mW
Nominal sensitivity @ 1 KHz: 113 dB/1 mW
Frequency range: 20-20000 Hz
Enclosure type: semi-open earbuds

The X50 are OVC’s more expensive, higher-quality earbuds. OVC was the Chinese OEM for many Western companies (Koss, Siemens, AT&T, Panasonic, LG, Samsung, Audio-Technica, Plantronics, Yamaha, V-Moda, etc. etc.); there’s an English website for OVC, http://www.ocvaco.com/, with a bit more background on just what OVC is.

Long story short, X50 are close to Yuin PK3 in price and performance. About 75% of the performance at 75% the price. Not as exciting or magical as the PK3, but with a larger soundstage and a bit more power to the sound (this is probably as powerful and “solid” as earbuds can get).

Yuin PK3

Enclosure type: semi-open, earbuds.
Frequency response: 15-20000 Hz.
Nominal impedance: 32-ohm +/-3.2.
Sensitivity, dB/1 mW: 120 +/-3.
Maximum input current: 400 mV.
Cable: straight, Y-shaped.
Price: $49 (ex. shipping).
Buy: here or here.

Excerpts from the review…

Yuin PK3 have a very headphone-like soundstage. Still not as large as even mini-headphones, but approaching the size and impact of real headphones. Detail’s as good as of some of the more expensive full-size headphones (a switch from AKG K-240S takes away some of the volume, makes everything somewhat smaller in scale, but does not take away detail).

Yuin PK3, like many Asian headphones, are also more intimate, warm, they sparkle with vital energy when playing music.

Earbuds usually don’t do bass.

Yuin PK3 have lots of bass (too much at times, even). It’ll depend on the source, but PK3 usually are powerful in the low end.

Even to a casual listener the PK3 didn’t sound much like earbuds and more akin to real headphones.

Yuin PK3 are perhaps the best earbuds for the money. An automatic upgrade from any headphones or earbuds bundled with a player. “Hi-fi earbuds” is a combination that can make anyone laugh - until listening to PK3.

Comfortable, with sound that rivals full-size headphones at twice the cost, with an oriental warm, sparkling character.

Even the most spoiled earbud snob (except perhaps of the very spoiled kind that won’t accept anything but white earbuds) will love those earbuds.

The full review.

In short: buy them.

Probably the most exciting revelation in earbuds.

Those are an automatic replacement for bundled earbuds. The $50 price might incite doubts, but Yuin PK3 are as detailed, powerful and lively as some of the more expensive headphones costing over a hundred.

The sparkle, liveliness and raw power of Yuin PK3 are unrivalled in this price category.

Yuin PK3 fit anyone properly, too, and they don’t even sound much like earbuds. They remind more of larger headphones, with a warm, powerful sound and a spacious soundstage.

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