Amazon.com: Fosi Audio K5 Pro Gaming DAC Headphone Amplifier Mini Hi-Fi Stereo Digital-to-Analog Audio Converter USB Type C/Optical/Coaxial to RCA/3.5MM AUX for PS5/PC/MAC/Computer : Electronics
TA-30 Tube Headphone Amplifier Tube Amp High Fidelity Desktop USB DAC 3000MW tzt | eBay
Turtle Beach Ear Force XL1 Xbox 360 USB Headset with Inline Amplifier | Groupon
Portable Headphone Amps
Apogee Groove – Portable USB DAC and headphone amp for Mac, iOS and PC
DAC-X3 mini stereo audio amplifier usb headset amplifier DC 12V | eBay
Amazon.com: Headset Amplifier Compatible with Polycom, Avaya, Cisco 7902 7905 7906 7910 7911 7912 Phone - Professional Swiveling Receiver Noise Cancelling Binaural Headset with Headset Amplifier for Call Center : Electronics
SYBA Multimedia SD-DAC63116 Multimedia USB 2.0 DAC 24 Bit 96 KHz Plus Stereo Headphone Amplifier - Walmart.com
Fresh From the Bench: SPL Phonitor One d Headphone Amplifier System | audioXpress