RKR Micro HP-1 
1x3 Stereo Headphone Amp

• Inputs: 1 stereo ¼” jack, 7.5 K ohms; plus 1 looping mono XLR jack, 30K ohms; ¼” input over rides XLR input
• Outputs: 3 stereo ¼” headphone jacks, 12 Ohms; XLR Plug looping from XLR input (on back)
• Power: 4 Internal AA batteries or 8-18V external D.C.; 2.1mm pin connector; Current draw – 10ma / headphones
• Max Level: 16dB
• Frequency Response (-3dB)  50Hz – 19,000Hz (100 Ohm load)
  Weight & Dimensions: 14 oz. With batteries, 3.75” wide, 5.25 long, 1.625” high.
   
• Features:
• VOLUME: Two buttons per output allow you to raise or lower the level of the sound for each headphone. The level will not change after power down / power up.
• MONO/STEREO: Automatic internal selection enables you to hear mono or stereo signals in both channels.
• POWER ON/OFF/LED: Connecting headphones to any output turns the amplifier on. Disconnecting all headphones turns the amplifier off. The LED detects a low battery condition.

Available in black and brushed silver

Sound Devices HX-3
2x3 Stereo Headphone Amp

• Inputs: 2 line level (stereo) XLR’s, 1 looping stereo 1/4”, one 1/8’ looping to 1/4”
• Outputs: 3 stereo 1/4” jacks, one 1/8” jack on output #1
  Power: 2 AA’s or external 5-17VDC, Bi-color LED
• Max Level: +18 dBu minimum with 600 ohm load, +16 dBu minimum with 300 ohm load
• Frequency Response: 10 Hz - 50 kHz, ±1.0 dB
• Weight & Dimensions: 1.7" x 3.7" x 5.5", 20 oz. w/o batteries
   
• Features:
• Volume: Three rotary volume controls, Peak LEDs for each channel
• Mono /Stereo: Global Mono/Stereo switch

More HP Amps (including AC powered & rack mounted) available from:

• ART
• Symetrix
• Samson
• Studio Technologies
• Presonus
• Whirlwind