Pass Labs HPA-1 Headphone Amplifier


The HPA-1 is a Headphone Amplifier and Preamplifier

The HPA-1 is Pass Labs' first headphone amplifier. It was designed by Jam Somasundram, former director of engineering at Cary Audio. After he joined Pass Labs in 2013, Somasundram spent a year conceiving the HPA-1.

The HPA-1 is a Class A headphone amp that also functions as a preamplifier. Somasundram designed it as a preamp first. It's more like Pass Labs' power amps, and it's designed to drive all dynamic and planar magnetic headphones. After its release in 2014, the HPA-1 was named Headphone Amplifier of the Year by The Absolute Sound and Best Headphone Amplifier by HomeTheaterHiFi, and was named Amplifier of the Decade by Stereophile Magazine. Its lucious, tube-like sound has earned the HPA-1 many fans over the years.

Key features:

  • Designed as a power amplifier rather than a typical headphone amplifier to be able to drive low impedance planar headphones from brands like HiFiMan, Audeze, Dan Clark, and more.
  • Works with headphones with impedances of 15 ohms to 600 ohms.
  • Low feedback wide bandwidth discreet design.
  • Class A direct coupled Mosfet output stage.
  • Custom low noise Toroidal power transformer with a Faraday shield.

Please make sure javascript is enabled in your browser.

The front panel features:

  • a single, locking Neutrik 1/4" headphone jack;
  • a large volume control knob; and
  • three buttons to select inputs or to engage the preamp output.

The rear panel features:

  • two pairs of single-ended analog inputs via RCA jacks (to connect to a CD player, turntable, etc.);
  • a set of switchable "preamp" line-level output jacks; and
  • a fuse and power switch.

HPA-1 Headphone Amplifier Specifications

Sold out

Sound Highlights: Neutral-warm, musical, big soundstage

Output power into 20 ohms: 3500mW

Output power into 300 ohms: 200mW

Sensitivity: 110dB SPL/1mW Sensitivity

THD + Noise: <0.005 at 1V out

Gain: 8dB

Frequency response 10Hz-100k: 1dB

Input impedance: 50K ohms

Output impedance: <2 Ohms

Power consumption: 6 watts

Dimensions: 4" H x 11" W x 13.5" D

Weight: 14lbs

Inputs: Two single-ended RCA

Output: One single-ended RCA (line), 1/4" TRS jack

***Free Blue Dragon Power Cable if ordered by December 31, 2021 - a $200 value***

This neutral-sounding cable features UP-OCC copper and is double shielded to ward off all outside interference.