Headphone Amplifiers

OPPO HA-1 Headphone Amplifier Review


OPPO HA-1 Headphone Amplifier Review Highlights

Best of 2014 Awards

Headphones, including earbuds, on-ear headphones, and over-the-ear headphones have exploded in the marketplace during the last few years. It seems that if your company doesn't have some form of headphone in your product portfolio, you just aren't up-to-date with what's happening.

Secrets of Home Theater and High Fidelity - John E. Johnson, Jr.

OPPO released their first headphones, the PM-1 (over-the-ear), and have followed that with the HA-1 Headphone Amplifier, just now becoming available ($1,199). The headphone output stage (as opposed to the preamplifier stage) is biased into Pure Class A, which is unusual, especially at the price. I found the sound to reflect this, with crystal clear details. With headphones, sometimes one can hear a hiss, which is the noise floor. I could only detect absolute silence, when music was not playing (in between music tracks) with the HA-1. Using the PM-1 headphones, I only had to turn the volume up to about 9 o'clock on the dial (- 18 dB in a range of - 80 db to + 6 dB), and that was with the output set to "Normal" rather than "High" (for headphones that need more power).

There are new ultra-high resolution digital music formats that are emerging, namely, 24/352.8 PCM and DSD128. Music in these formats is just becoming available, and I downloaded some samples from 2L, a music company in Norway. You play these files from your computer, through the USB DAC connection on the HA-1. I'm not really sure I could detect a difference between those formats and 24/192 or DSD64 (the current SACD or "DSD" format) which have been available for some time. Nevertheless, they sounded fantastic, played on the HA-1 and PM-1. It even supports DSD256 digital audio, which is not yet available to the consumer! OPPO is planning for things that are still around the corner and not visible.

Other connections on the HA-1 include a digital coax (RCA) input, digital XLR input, digital mobile input (a USB port on the front panel to play music from your iPod, iPad, or iPhone), Bluetooth, RCA unbalanced analog output, and XLR balanced analog output. Of course, the main outputs are on the front, including a ¼" non-balanced output, and a 4-pin balanced output, which I used with the PM-1 balanced headphones.

Here is a video that describes the main features of the HA-1:

And, wow! What a sound. Built like a tank, and gets as hot as a tank in the Sahara due to its Class A output. If you have purchased the PM-1's, the HA-1 is a no-brainer. Get one now! If you have other headphones, get one as well.

Introduction to the OPPO HA-1 Headphone Amplifier Review

Recenty, we reviewed the OPPO PM-1 balanced headphones, and were in awe of the sound. As I neared the end of writing the review, the new OPPO HA-1 headphone amplifier arrived.

When I opened the box, I was in for a real surprise. Great design. Myriad features. Luscious sound.


  • Design: Fully Balanced; Pure Class A Operation in Output Stage
  • Codecs: Up to 24/384 PCM and DSD256
  • Power Output: Preamplifier: 4.6 Volts RMS through Balanced Output, 2.3 Volts RMS through RCA Unbalanced Output; 2.4 Watts RMS through Balanced Headphone Output, 0.6 Watts RMS through Unbalanced Headphone Output into 600 Ohms
  • Discrete Circuitry in Output Stage; Op-amps in Preamplifier Stage
  • ESS Sabre32 Reference
  • Adjustable Gain Settings: High, Normal
  • Asynchronous USB DAC Input
  • Remote Control: IR; Bluetooth App Works with iPhone as Remote Control
  • Dimensions: 4.8" H x 10" W x 12.2" D
  • Weight: 13 Pounds
  • MSRP: $1,199 USD Direct from OPPO
  • OPPO
  • SECRETS Tags: OPPO, Headphone Amplifiers, Balanced, Bluetooth

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