HPAJr Single Channel Mini-Amp/Signal Booster
The HPAJr Headphone Amplifier is a compact, battery / external dc powered unit designed to interface your favorite full-sized professional headphone to a variety of audio input sources. Now you won't be limited to small, poor quality "in-ear" or "walkman" type headphones for your monitoring or listening needs. The HPAJr will allow you to drive headphones of many impedances to more than adequate listening levels with a full, rich sound not obtainable at low output levels or with lightweight "personal" earpiece / headphones. You can use the HPAJr for such professional purposes as increasing monitor levels from: mixers, portable VCR's, tape recorders or R-DAT's; personal listening to keyboards and synthesizers or monitoring of home studio gear. Compact and durable, the HPAJr comes with a sturdy belt clip for complete portability.
Frequency Range: 5Hz - 30kHz.
Operational Modes: Stereo or Mono selectable.
Input: " Phone jack. 50k ohm impedance.
Input Sensitivity (Selectable): @ -10dBm = 245mV
  @ -30dBm = 25mV
Output: " Phone jack. 4 ohm - 600 ohm impedance.
Total Output Level:
Power Supply Output Z Output Power Output Voltage
12V 600 ohms 120mW 6V
12V 8 ohms 3W 3.5V
18V 600 ohms 160mW 7V
18V 8 ohms 5W 4.5V
Power requirements: Batteries - 2 - 9V (alkaline preferred).
  External - 12Vdc - 18Vdc @ 300mA via 3.5mm jack
Size (W x H x D): 2-7/8" x 5" x 1"
Weight: 8 oz.
Case Material: Painted aluminum
Approvals: CE, RoHS and WEEE
  Emissions: - EN 55022 B - FCC Class B
  Immunity: - EN 55024 B