Simple and versatile.
Simplicity is the HP4’s hallmark. You get left and right line inputs, left and right line outputs with level control, and the four headphone outs. You can sum the stereo signals to mono, adjust the individual headphone levels, and mute the rear-panel Monitor outputs while leaving the headphone outputs active. So while the HP4 is simple to set up and use, it has all the features you need to create a versatile headphone system.
Compact and expandable.
The compact HP4 can sit on a tabletop or can be screw-mounted to a standard rack tray (not included), where it requires just 1/3 rackspace. And if your needs grow, you can use the line outputs to feed the inputs of a second HP4 or the larger HP60 headphone amplifier. So quit struggling with mediocre headphone amps. Get the HP4 and hear everything loud and clear. You owe it to your music.