The Fiio K7 headphones DAC is a great little mains-powered desktop option
FiiO K7 Review - Headfonia Reviews
Fiio K7 - The Little Black Box that Thinks it Can Do it All! - Honest Audiophile Impressions
FiiO K7 Review - Headfonia Reviews
FiiO K7 review: This outstanding DAC drives headphones, too
The BEST value in budget audio! FiiO K7 Review
FiiO K7 Review – An Improvement Over The K5 Pro? - Home Studio Basics
Fiio K7 Review - Major HiFi
The most competitive and cost-effective desktop balanced Bluetooth DAC/Amp within the 300-USD range. Adopts the six-stage audio circuit as in FiiOs high-end devices, and features 2 AMKs latest AK4493SEQ DACs and dual THX AAA 788+ amps. Supports multiple outputs- 4.4mm balanced out, 6.35/3.5mm single-ended out, as well as multiple inputs- USB, optical, coaxial, and AUX in.
FiiO K7 Desktop USB DAC and Headphone Amplifier Red Volume Control, 32 Bit/384KHz, Coaxial SPDIF Optical, 1/4 4.4 mm RCA K7RED
Customer reviews: FiiO K7 Desktop DAC and Amplifier
FiiO K5Pro ESS Amplifier Headphone Amps Stereo High Resolution Portable Desktop DAC 768K/32Bit and Native DSD512 for Home Audio/PC 6.35mm Headphone Out/RCA Line-Out/Coaxial/Optical Inputs (Black) : Electronics