LD Systems HPA 1

Amplifier for headphones and wired IEM

The LD Systems HPA 1 is a versatile headphone amplifier with high power output for stage, studio and home recording and is the perfect solution for wired in-ear-monitoring.. The compact device in a rugged, ergonomically shaped plastic housing with soft-touch surface and practical belt clip is very extensively equipped.

In addition to locking XLR connectors for the stereo signal L/R input, the HPA 1 has a balanced 3.5 mm stereo jack as AUX input, which can be used in parallel for clicks or playback. It is protected for safe operation against excessive input levels; a hollow pin socket with negative internal contact enables the connection of a network adapter for fixed operation.

A 3.5 mm stereo jack is provided as earphone and headphone output. Volume level and balance can be set with easy-grip knobs, a push-button switches between the summed mono and stereo signals. A full-fledged limiter is integrated for distortion-free playback and as protection against feedback.

The LD Systems HPA 1 has bi-colour LEDs to facilitate the features overview, which displays the response of the limiter during peaks and the battery status. At 165 grams, the headphone amplifier is distinctly light-weight and can be operated for up to 12 hours thanks to a high quality 9 V block battery.



  • Compact and powerful headphone amplifier
  • Also ideal for wired in-ear monitoring
  • Balanced XLR inputs L/R
  • 3.5 mm AUX input for click and playback
  • Precise volume and balance controllers
  • Built-in limiter for distortion-free playback and feedback protection
  • Switchable mono sum for a focused sound
  • Ultra stable housing with soft-touch surface
  • Practical belt clip for direct on-body operation
  • Connection for a 9 V DC adapter

Additional information

Product Type

Headphone Amp:


AUX In (Stereo)

Input Connectors

3.5 mm stereo jack (AUX In) , XLR-F (L + R Input, balanced)

Input Impedance

10000 (3.5 mm jack) Ohm(s) , 6000 (XLR In) Ohm(s)

Input sensitivity

-6 (3.5 mm jack) dBV, 3 (XLR In) dBu



Output Connectors

6.3 mm jack

Power Output

4 x 100 mW


Balance L/R , Power / Volume , Stereo/Mono (Focus) switch


Battery (low battery: red) , Peak (Amber) , Power LED (Power ON: green) , Signal (green)

Current Draw

Nom. 0.07 A / Max. 0.15 A

Cabinet Material


Cabinet surface

Soft Touch

Cabinet Colour



80 mm


42.5 mm


133 mm


0,155 kg

Accessories (included)

Belt Clip

Max. Input Level

7 (3.5 mm jack) dBV, 16 (XLR In) dBu

Protection circuits

Audio Limiter , Max. Input leveling , Power OFF – Mute relay

Headphones ouputs

3.5 mm TRS

Power Output (1% THD @ 33 Ohm Load)

Power Output (1% THD @ 33 Ohm Load)

Minimum connected impedance

16 (per channel) Ohm(s)

Frequency response

20 – 40000 Hz



Operating voltage

9 V block , 9 V DC power supply


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