The Presonus HP4 headphone amp features 4 headphone amplifiers (150mW per channel), each with a headphone level control and mono summing switch.
As with other Max Rack products, simplicity is the hallmark of the HP4. You get left and right line inputs, left and right line outputs with level control, and the four headphone outs. You can globally mute the headphone outs, adjust the overall headphone level, and sum the stereo signals to mono.
Like other processors in our Max Rack series, the HP4 can sit on a tabletop or can be mounted in 1/3 rackspace, using the optional 3UMR rack adapter. And if your needs grow, you can use the line outputs to feed the inputs of a second HP4 or an HP60. Chain as many headphone systems as you need.