Kuumakse al. 
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.
Inputs
Connector Type ¼” TRS, balanced
THD+N 0.0025%, 1 kHz, unity gain
Max Input Level +18 dBu, <0.5% THD+N, unity gain
Input Impedance 10 kΩ
Frequency Response 20 Hz - 20 kHz, ±0.5dB
Monitor Outputs
Connector Type ¼” TRS, asymmetrical, impedance-balanced
THD+N 0.0025%, 1 kHz, unity gain
Max Output Level +18 dBu, <0.5% THD+N
Output Impedance 51Ω
Frequency Response 20 Hz - 20 kHz, ±0.5dB
Headphone Outputs
Connector Type ¼” TRS, stereo
Max Output Power 130 mW/Ch., <0.5% THD+N, 60Ω load
Frequency Response 20 Hz - 20 kHz, ±0.5 dB, 60Ω load
Headphone Impedance Working Range 32Ω - 600Ω
Power
External Adapter Type +12 VDC, 1000 mA, center pin positive
Physical
Dimensions 1/3U rack-mount (with standard rack tray, not included)
Height 1.75” (44.45 mm)
Depth 5.5" (139.7 mm)
Width 5.5” (139.7 mm)
Weight 5 lbs (2.27 kg)
