Fosi Audio PH04 Headphone Amplifier vs Douk Audio U3 Mini Headphone Amp

These solve different problems. The Fosi PH04 is a four-way splitter: one stereo source, four independent volume knobs, all on 3.5mm jacks, so several people can listen at once. The Douk U3 is a single-output Class A amplifier built to drive hard-to-drive headphones, with far more output power and a swappable op-amp. Build quality is the weak spot on both: the U3's 4.1 rating comes with complaints of hiss, a scratchy stepped knob and an intermittent jack after six weeks, and the PH04 is a light plastic-feeling 175g box with modest output. Buy the Fosi for shared listening; buy the Douk only if you have high-impedance headphones and a clean 16-18V supply.

• Choose the Fosi Audio PH04 if several people need to listen to one source at once and each needs their own volume.
• Choose the Douk Audio U3 if you have one pair of demanding high-impedance headphones and want a warm Class A amp you can op-amp roll.