Pass Labs HPA-1C Stereo Headphone Amplifier

Building on the legacy of the award-winning HPA-1, the new HPA-1c raises the bar in headphone amplification. While the core amplifier circuit remains true to its original, highly regarded design, Pass Labs has taken the opportunity to refine and enhance its performance.

Driven by the need to replace end-of-life components, the HPA-1c features an upgraded power supply and improved circuit board grounding. These updates deliver a cleaner, more stable power foundation—resulting in lower noise, tighter regulation, and a blacker background.

Also added is a local regulation to the servo circuitry, achieving approximately a 10 dB improvement in overall noise performance.

The result? Greater low-level detail and improved clarity, especially with high-sensitivity headphones where it matters most.

In addition to its excellence as a headphone amplifier, the HPA-1c continues to function as a high-performance line-level preamplifier. With its discrete, class A design and robust output stage, it's equally at home at the heart of a reference speaker system.

Headphone Output

The HPA-1 delivers up to 2 watts into 32 ohms, with a low output impedance of 2 ohms.
It's designed to drive most dynamic and planar magnetic headphones with authority, including low-impedance and high-sensitivity models.

Preamplifier Output

The preamp section is capable of driving a typical power amplifier load (10kΩ or higher) with very low output impedance.