Behringer MICROAMP HA400 Ultra-Compact 4 Channel Stereo Headphone Amplifier,Silver, 4.08 x 2.25 x 1.83 inches

Amazon.com If you're tracking more than one musician at once, or if everyone in a group wants to listen to a playback, you need a monitor distribution system. The compact, flexible HA400 can power up to four pairs of headphones and up to four independent volumes. A Simple Solution Grab this super-compact amp during your sessions to power practically any headphones--four of them at the same time, to be exact. This allows four people in your studio to listen to the main mix while recording, and each listener can determine their own volume level using the dedicated output level controls. Quality Amplification The HA400 contains 4 high-power stereo amplifiers that maintain the highest sonic quality even at maximum volume levels. These ultra-low-noise 4580 operational amplifiers are included for outstanding audio performance--the same op amps found in "full-size" audio equipment. What's in the Box Behringer HA400 4-Channel Stereo Headphone Amp, Power Adapter, User's Manual Product Description Ultra-compact 4-channel stereo headphone amplifier.