"The HA-1 is a Killer"
The Oppo HA-1 is a discrete 'Class A' balanced headphone amplifier with the same versatile approach as its Blu-ray players. The HA-1 is a high performance headphone amplifier, and it doubles as an asynchronous USB DAC, a stereo preamplifier, a digital audio dock for mobile devices, and a Bluetooth audio streamer.
A special "Home Theater Bypass" mode can be assigned to any input source, making it very easy to integrate the HA-1 as a stereo pre-amplifier into a home theater sound system.
"The HA-1 is a killer," notes John E. Johnson, Jr. in Secrets of Home Theater and High Fidelity, May 15, 2014. "I got one is silver and it's gorgeous to look at and dazzling to listen to. Should I say, 'Highly recommended,' or have you already assumed so?"
"From a straightforward up-to-date techs-and-specs position the Oppo is currently unchallenged at its price point. It is a features-driven product with spectacular results. It is so much more than a headphone amplifier in the same fashion that an Oppo player is so much more than just a Blu Ray transport," raves Computer Audiophile, June 30, 2014.
Fully Balanced Design
The analog audio section of the HA-1 is a fully balanced design with an emphasis on keeping the audio signal in the analog domain once it leaves the DAC. The HA-1 is anchored by a hefty toroidal power transformer. Linear power regulators and filters with custom made capacitors ensure that the headphone amplifier has a clean power source with plenty of reserve energy.
The fully balanced 'Class A' power amplification section uses hand-picked and paired discrete components to ensure symmetry. A motor-driven precision volume control knob allows for both manual and remote control volume adjustment while keeping the audio in a pure analog audio path.
For digital audio, the signal runs in balanced mode all the way from the DAC to the output jacks. Balanced analog input is kept intact, and single-ended input is converted to balanced at the input buffer. All single-ended outputs are derived from the balanced signal as well. The balanced design provides better common-mode noise rejection and improves signal quality.
The balanced headphone output provides twice the voltage and four times the power of the single-ended output, enabling the HA-1 to drive the most power hungry headphones. It also provides better channel separation by eliminating the common ground return path.
Especially Suitable for High-resolution Digital Audio Playback
The HA-1 is especially suitable for high-resolution digital audio playback. Its digital inputs include coaxial, optical, balanced AES/EBU, and an asynchronous USB DAC. It is easy to connect the HA-1 to digital audio players or to a computer running the listener's favorite playback software. The USB DAC supports PCM audio up to 384 kHz 32-bit resolution and DSD audio up to 256x the CD sample rate. The same ESS 9018 Sabre32 Reference DAC and output driving stage used in Oppo audiophile Blu-ray players ensure extremely low noise and low distortion performance.
Analog and Digital Connectivity
The 'Class A' headphone amp and preamp functionality provide fully balanced analog inputs and outputs, purely analog volume control, and an adjustable headphone gain switch. For headphone excellence, you have a choice of using the four-pin balanced XLR or the traditional quarter-inch headphone jack. Line level analog inputs and outputs are provided with both RCA and balanced XLR sockets.
The numerous digital inputs include coaxial, optical, AES/EBU, and an asynchronous USB DAC input that supports PCM, DSD64 and DSD128.
Clean Signal Path
The HA-1 uses an analog potentiometer (the familiar volume knob) to control the volume. By avoiding re-digitizing the audio signal for volume adjustment, the HA-1 provides a clean signal path for the audio. At the same time, the convenience of modern digital volume control is not lost. A remote-controlled motor turns the volume knob and a 10-bit analog-to-digital converter samples the signal to display a numeric dB level.
Toroidal Power Supply
A toroidal power transformer offers superior power efficiency and much lower exterior magnetic fields over traditional laminated steel core transformers. The HA-1's toroidal linear power supply provides a very clean and robust power source to the audio components.
ESS Sabre32 Reference DAC
The DAC is one of the most important components for digital audio playback. The SABRE32 Reference ES9018 from ESS Technology is the world's best performing 32-bit audio DAC solution targeted for high-end consumer applications and professional studio equipment.
With the ESS patented 32-bit Hyperstream™ DAC architecture and Time Domain Jitter Eliminator, the SABRE32 Reference DAC delivers an unprecedented DNR (Dynamic Range) of up to 135dB and THD+N (Total Harmonic Distortion plus Noise) of -120dB, the industry's highest performance level that will satisfy even the most demanding audio enthusiast.
The HA-1 is compatible with Apple's iPod, iPhone, and iPad for use as an external DAC, enabling the listener to directly tap into digital music played from these devices. For additional convenience, the Bluetooth audio transport with high quality aptX CODEC sets music free from your mobile phones with a performance boost.
The HA-1 sports a classic design with contemporary elements. It is a desktop component housed in an aluminum chassis, and the familiar volume and source selection knobs are complemented by a 4.3-inch color screen for easy operation. While music is playing, the screen can show a classic VU meter, a modern spectrum display, or detailed technical information about the audio signal. A supplied IR remote and a smartphone app provide complete control and convenience.
Remote Control App
The Oppo Remote Control app provides a convenient way to control your OPPO HA-1 Headphone Amplifier from your mobile device. You will be able to switch input sources, adjust volume, mute/unmute audio, set the screen brightness level, and even control playback of digital audio sources.
Trigger Input and Output
The HA-1 features 12V trigger input and output. When used as a stereo pre-amplifier, the trigger output can turn on your power amplifiers automatically when the HA-1 is turned on. You can also turn on the HA-1 automatically by connecting its trigger input to the trigger output of a source device or a surround sound processor.
"The HA-1 is a killer. I got one is silver and it's gorgeous to look at and dazzling to listen to. Should I say, 'Highly recommended,' or have you already assumed so?"
– John E. Johnson, Jr, Secrets of Home Theater and High Fidelity, May 15, 2014
"From a straightforward up-to-date techs-and-specs position the Oppo is currently unchallenged at its price point. It is a features-driven product with spectacular results. It is so much more than a headphone amplifier in the same fashion that an Oppo player is so much more than just a Blu Ray transport. Innovation, durability, flexibility and enough connectivity specs to make your head spin give this little contender both its charm and its value. Its on hand compatibility paired with a sleek digital side makes it one of the most complimentary components for desktop listening in the sub $2000 range.
– Computer Audiophile, June 30, 2014