Pros: SQ, Form Factor, Battery Life, USB OTG, Adjustable Gain
Cons: Minimal EQ Change, UI, Accessories
iBasso has set the standard for balance between price and performance with the DX50. This DAP is like a stockier, more sturdy version of an iPod.
With better SQ.
And USB OTG.
With regards to appearance it's a nice piece of hardware. The brushed metal case looks great and is rather scratch-resistant in my experience. I was wary of the three button layout AND touchscreen, but after getting used to it, I think its a great design. I can use the touch screen to navigate, adjust EQ, and create/manage playlists. Then after I put the 50 back into my pocket the three buttons make it very easy to play/pause and skip/restart already playing tracks. The other buttons are also easy to use without having to lay eyes on the player. These include volume, gain, power, and hold buttons.
With regards to the sound quality, it's just great. The sound has changed slightly and improved over time thanks to the steady firmware updates provided by iBasso, however, in general a rather neutral and sometimes bright presentation has remained. The soundstage is very good and I've yet to hear a better detail retrieval from a DAP. Something to note: the slightly north of neutral presentation makes an excellent pairing with slightly warm headphones. Dsnuts put it best when he said that the DX50 - a slightly bright DAP - pairs well with warmish headphones/IEMs while the Fiio X3 - a warm DAP - pairs best with slightly bright headphones/IEMs. It also bears mentioning that the 50 has three adjustable gain settings. The most sensitive IEMs will hiss on the LO setting (have you found a standalone DAP that doesn't!?), but overall the gains provide excellent power. I used the HI gain setting to power my HD600s and never once thought that the device couldn't handle it.
That being said, an amp does ENHANCE the already great SQ. I pair mine with the neutral Arrow 4G which lowers the noise floor for my IEMs and opens the soundstage width and depth. Also, the EQ tailoring options on the 4G sound better to me than the native EQ adjustments on the DX50.
The battery life on LO gain is around 14-16 hours and obvisouly, will change depending on audio file quality and gain setting.
One of my favorite things about this DAP is its USB OTG feature. I'll gladly take this capability over USB DAC function (which I'm told won't be available for the DX50). It gives me the option to hook up any portable USB storage device and let the DX50 browse/play audio files. So. When I go on road trips, I bring my 128gb jump drive and that's all the music I could ever need! No more carrying around multiple MicroSD cards!
The qualms I have with the DX50 are few. 1. The native EQ settings don't do much. There are preset settings and the individual frequency bands can be adjusted. However, when I adjust them, I barely hear a difference. New FW has fixed this. 2. The included accessories could be better. I'm sure that the minimal packaging/accessories keeps the price down on this device, but a decent silicone case or cover would be great, along with some sort of user manual. It also bears mentioning that the UI which some people find quirky to say the least, it just fine. It has steadily improved over the course of this DAPs life and continues to get better. It's a UI based in Android and is very intuitive and easy to use. Much better than the X3's design.
Overall this DAP from iBasso is highly recommended. It is around the same price as a 160GB IPC, however, it offers better SQ, virtually limitless storage space thanks to USB OTG, and a better DAC/Amp implementation.