1、SAME INPUT AND OUTPUT: This machine adopts the circuit pre attenuation compensation and tone NE5532, when the power is off, the attenuation is ‑15db, when the power is on, the NE5532 amplifies the compensation, and the gain is 0db, that is, the input and output signals are the same 2、LOW POWER CONSUMPTION: The DC power supply should try to use a excellent low ripple power supply. When the input signal amplitude is less than 1v, 12v power supply is sufficient. When the input signal is greater than 1v, please increase the power supply voltage, the maximum power supply voltage is 24v 3、EASY SETUP: No special software, apps or drivers needed to install, a true plug and play digital audio adapter 4、WIDELY COMPATIBLE WITH ALL AUDIO DEVICES: Inputs fit DVDs, CDs, set top boxes, MP3s, TVs, cell phones, computers, tablets, turntables, sound cards, guitars, basses, electronic musical instruments, game consoles or other devices. Output suitable for speakers, subwoofers, Sound Blasters, reverbs, AV receivers, post amps, headphones, etc. 5、VOLUME CONTROL: Full metal housing can ensure good quality, with bass and treble control, can be used as preamp or volume controller for PC, for OS X, or computer