Ultra-compact headphone amplifier system for studio and stage applications.This Headphone Amplifier has 4 ultra-low-noise NJM4580 operational amplifiers and 1 high-power stereo amplifiers-NJM4556. Premium analog circuitry and design delivers an ultra-low noise floor and high headroom. This headphone amplifier share a single stereo source with up to 4 pairs of headphones.SNR (signal-to-noise ratio)S/N：>100dB. Enjoy ultra-low noise music environment. This headphone amp has featuring High fidelity analog circuit ,High power output, large dynamic, low distortion sound quality! When you and your friends are sharing the audio source, each person can independently control the volume of their headphones. With a heavy-gauge steel chassis, long wear potentiometers and switches. It is convenient for you to turn on/off the compact headphone power amplifier with a power switch anytime and anywhere,saving energy when enjoying high stereo audio quality. Powered via the included 12V AC adapter.Comes with 2-Pack 6.35mm 1/4 inch to 3.5mm 1/8 inch Male to Female Stereo Jack Adapter for free.