The Echo Nano borrows the old iPod Nano’s silhouette — metal scroll wheel, 0.91-inch OLED, 33.5g — but puts a dedicated CS43131 DAC chip behind it instead of a firmware update wall. The microSD slot takes cards up to 256GB. Plug it into a phone or laptop over USB and it switches to UAC mode, bypassing that device’s built-in audio chip entirely. $50.