Audirect Whistle – Mini Portable DAC Website: Audirect.cc Technical Specifications +121db DNR -115dB TND+N, 2Vrms into 600Ω -100dB THD+N, 49mW into 32Ω Resolution: up to 32 bit/384kHz sampling or 1bit/2.8MHz/5.6MHz DSD Dimensions: L: 51mm, W: 14mm, H: 14mm Price: U$D 99 Accessories: Micro USB to Micro USB cable Micro USB to USB Type-C cable Micro USB to Apple Lightning cable 3.5mm to 3.5mm Aux. cable Design The Whistle DAC is a very compact and well-built device. The outer material is made of metal, aluminum it seems, painted in either gray or red color (depending on the model). The surface is very smooth and despite the triangle shaped design the edges are well rounded. It is a very simple portable unit, with a Micro USB input connection on one side and standard 3.5mm output on the other. There are also a two Led lights to indicate the music format being played, PCM or DSD. Connectivity The Whistle can be connected to a personal computer, tablet or smartphone. For Windows systems it is needed to install an extra software for the drivers. Unfortunately, it was not recognized with two of Samsung Galaxy phones I tried, but seems to work fine with iPhone devices. The Whistle volume is adjusted by the device it is connected to. With Windows PC it can get too loud already even before reaching the half of volume steps. Sound Quality The Whistle sound performance was tested with various kind of gears, IEMs, earbuds and portable headphones, like the Vsonic GR07, Dunu DK-3001, MeeAudio P2, Fiio EX1ii, VE Monk+, Asura and Zen, Sennheiser HD-25 ii and Grado SR80. The gain and improvement in sound were more noticed with the open earbuds and headphones rather than with the closed In-ear sets. Overall, the Audirect Whistle small DAC offers a fuller sound from lows to mids with a smoother yet detailed upper end. It shows pretty much no coloration to the sound, which is quite a good feature for any DAC, but brings out a more natural tonality. The bass is larger and better layered without showing a higher mid-bass quantity. Sub-bass extension was better noticed on with the HD25 and Grado sets as both benefit from some extra amplification. The midrange remains very clean and slightly more forward with a nicer texture for vocals. No real gain on instruments separation though, but it keeps the detail and positioning. Treble has a better control, especially with brighter sets, being better rounded and very slightly smoother overall. The less favorable improvements are in stage dimensions; it doesn’t sound smaller, but still not as wider as could be expected. Compared next to a similar DAC such as the Zorloo ZuperDAC, the differences are easily noticed. The Zorloo has a more v-shaped presentation with a warmer low-end and less forward midrange but with a wider soundstage, while the Whistle is cleaner towards the midrange and highs and more natural in presentation. Overall, the Audirect Whistle DAC is a very compact and comfortable device, fairly well built and easy to use. My only complaint would be the need of extra drivers which is a bit annoying for the 2017, and the lack of volume control. That aside, the sound presentation is still enjoyable for a small and simple audio gear. Lastly, my thanks to Audirect for providing the Whistle unit for review.