Pyle | | 4-Ch. Stereo Headphone Amplifier | Black | Best Buy

$26.99

Donner Music | | Donner EM1 Personal In-Ear Headphone Amplifier | Gray | Best Buy

$52.99

Ifi Audio | | micro iDSD Signature Finale Portable Headphone Amp and DAC, MIDI Switcher & Distribution Hub, Portable DAC | Best Buy

$449.00

Donner Music | | Donner EM2 Personal In-Ear Headphone Amplifier | Gray | Best Buy

$62.99

Sennheiser | | HDV 820 Digital Headphones Amplifier | Black | Best Buy

$2249.99