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 PHA40 can power up to four pairs of headphones and up to four independent volumes. 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. The PHA40 contains 4 high-power stereo amplifiers that maintain the highest sonic quality even at maximum volume levels. These ultra-low-noise operational amplifiers are included for outstanding audio performance.
Bought this to get a little more volume from the new ATH-M40 headphones. Still testing but I'm quite surprised at the clarity and lack of distortion as I raise the volume. Doing what I wanted at an amazing price. It also seems to be doing fine runningmy small (cheap) desktop speakers on a seperate channel. Construction seems more than adequate. Reommended for intended use. (Posted on 6/8/2016)