A great pairing for laptops and smartphones, the Topping NX4 DSD is a compact DAC/amp loaded with impressive specs. It’s equipped with the well-regarded Sabre ES9038Q2 DAC, along with an XU208 USB bridge, and it supports some of the highest-resolution audio—including 32 bit/768 kHz, DSD256 (DoP), and DSD512 (native). For easy use when you’re on the go, the NX4 DSD comes with rubber bands and Velcro feet to attach to your smartphone or digital music player. It provides 28 hours of playback when the headphone amp is used and 7.5 hours of playback when the DAC and amp are used together. Featuring a full aluminum shell, the unit is smaller than your average phone and weighs just over 5 ounces.