In this video I review the Fosi Audio DS3 dongle DAC, Fosi’s latest $99.99 dongle that they’re calling the world’s first XMOS-powered USB dongle DAC. I go through the quick unboxing (DS3, USB-C to C cable, and a USB-A adapter), then talk about the quirky build: CNC aluminum body, a glass back, and a front “window” that I originally thought would light up. The always-on RGB behind the glass is slightly annoying, and I’m really hoping the upcoming web app gives us a way to turn that off. Feature-wise, the DS3 has HiFi mode (UAC2) and Gaming mode (UAC1), gain switching, 8 digital filters, and gaming DSP effects like FPS mode and a virtual 7.1-style expansion. The big promise is an 8-band PEQ through a web-based app (after firmware), but it wasn’t available when I made the review—so if PEQ is the main reason you’re buying, I’d wait and see how it’s implemented. Sound-wise, compared to the FiiO KA17 and iBasso DC07 Pro, the DS3 comes off with the most controlled/rounded treble, a bit more bass quantity, and a slightly smaller stage depending on your IEMs. I also measured efficiency: it idles around 54 mA and plays around 95 mA in UAC2, which is pretty good for phone use.