Amazon.com: FiiO Q3 Amplifier Headphone Amp High Resolution DAC DSD512 for Smartphone/PC/Laptop/Home/Car Audio 2.5/3.5/4.4mm Output : Electronics
FiiO K5PRO ESS Review — Headfonics
Amazon.com: FiiO K3 DSD256 | 384K/32Bit USB-C DAC and Headphone Amplifier for Home and Computer(3.5mm Single Ended/2.5mm Balanced/Coaxial and Optical Digital Outs) (K3 Titanium) : Electronics
FiiO K7 review: This outstanding DAC drives headphones, too | TechHive