Looking at an AudioQuest DragonFly but wishing it had a TOSLINK input as well as USB? Hifime have you covered. Their matchbox-sized S2 USB DAC sports a microUSB input to work with PC/Macs and smartphones plus a mini-TOSLINK input for hooking in a TV, games console or Google Chromecast Audio (RIP). Only data can travels across a TOSLINK connection so the microUSB needs to see 5V of power from a ‘phone’ charger or battery pack.
The USB’s input power draw falls between 30mA and 50mA; well below the 100mA limit imposed by Apple on its iOS devices. From Hifime’s product page: “We have tweaked the settings on this version so that iPhone doesn’t (incorrectly) believe that it requires too much power.”
Like the DragonFly range, the S2’s USB input works with any OS without driver intervention and is limited to 24bit/96kHz. No MQA.
Inside the S2, D/A conversion is executed by an ESS 9038Q2M chip. USB reception comes from an ESS SA9023 but no word on the power supplies’ noise profile. Output staging and headphone drive from an ESS SABRE9602, the latter pushing 49mW into a 32 Ohm load as typically presented by smartphone-friendly headphones. The S2’s line-level output is 2V – enough for loudspeaker amplifier connections.
On smartphone hookups, we must get into the weeds on cables. iPhone users can purchase Hifime’s own ‘chipped’ adapter (shown above, ∼€27) that converts the iPhone’s Lightning output to the S2’s microUSB input. Android users can pick up their choice of microUSB-microUSB or USB-C-microUSB adapters (∼€5 each).
Of course, no amount of hardware-based speculation will tell us how the S2 USB DAC sonically stacks up against any of AudioQuest DragonFlys but at ∼€80 the Hifime unit is sufficiently affordable that readers can find out for themselves.
Further information: Hifime