iFi ZEN DAC V2 Desktop USB DAC and headphone amplifier at Crutchfield
Cirmech Pcm2706 Hi Usb Soundcard Diy Kit Usb Dac Spdif Android Compatible Microusb Windows Without Driver Plug And Play Wm-017 - Headphone Amplifier - AliExpress
CS8416+CS4398 DAC Kit Support USB + coaxial DAC Board | eBay
Sound Blaster X4 - Hi-res 7.1 External USB DAC and Amp Sound Card with Super X-Fi® and SmartComms Kit for PC and Mac - Creative Labs (United States)
DIY DAC Kits and Easy Mods
Sound Blaster X4 - Hi-res 7.1 External USB DAC and Amp Sound Card with Super X-Fi® and SmartComms Kit for PC and Mac - Creative Labs (Pan Euro)