As I mentioned previously, none of the other models here work connected directly to Apple's adapters, but they do work when connected via a powered USB hub. This is a nice option to get high-quality sound from an iOS device at home, but it's obviously not particularly portable.
What about Android devices? Well, it's complicated — perhaps unsurprisingly. If your device supports USB-on-the-Go, these DACs may work. When I briefly tested the DACs with the Samsung Galaxy Note 2, only the MicroStreamer worked immediately. I've seen reports of other devices working, particularly with third-party software. If you'd like to know if your Android hardware and software will work with one of these DACs, my best advice is to do some research — this post (and thread) on Head-Fi is a good place to start.
A few years ago, any of these models (along with Arcam's rPAC) would have been best-in-class. You really can't go wrong with any of them — each provides great sound quality and will improve on your computer's built-in audio hardware. The differences between them can seem subtle, particularly if considered in isolation. However, the Meridian Explorer offers the best audio quality overall, befitting its $300 price, and its optical output can be useful. The AudioQuest's $149 DragonFly offers the next-best overall sound quality, and the fact that it does so at half the price of the Explorer makes it the best value here. That value, combined with the DragonFly's convenient design, make it my favorite model overall.
In a few cases, however, I would recommend other models over the Explorer or DragonFly. HRT's $190 MicroStreamer almost matches the DragonFly's sound quality and price, and some listeners may prefer its clear sound or find its cool iOS compatibility worth the price premium. If you primarily listen to difficult-to-drive, full-size headphones, the CEntrance DACport and Arcam rPAC will outperform even the Explorer with those headphones, and each costs about $50 less. The Arcam has the better DAC, while the DACport has the better amp.
While I liked both the Audioengine D3 and Cambridge Audio DacMagic XS, it's difficult to recommend them given that each is more expensive than the DragonFly but neither matches its sound quality. However, the DacMagic XS is the least expensive model that plays 192 or 176.4 kHz files.
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