Oppo HA-1 Headphone Amplifier

Here we have what manufacturers OPPO describe as a Headphone Amplifier. In fact the HA-1 is slightly more than this as it can also act as a DAC and pre-amplifier with its variable outputs and has a single input for a further analogue source component. It comes in good fully working condition noting some minor imperfections, in its original packaging, with reprinted manual, mains cable and our regular three month warranty.
OPPO Say….
The HA-1 Headphone Amplifier draws upon the proven circuit design of the BDP-95 and BDP-105 Blu-ray Disc players. We designed the HA-1 headphone amplifier using the same universal approach we take with our Blu-ray players, so apart from being a high performance headphone amplifier, the HA-1 functions as an asynchronous USB DAC, stereo pre-amplifier, digital audio dock for mobile devices, and a Bluetooth audio transport.
The HA-1’s analogue audio section is a fully balanced, differential design with a Class A power amplifier circuit that is capable of driving the most difficult of headphones. Throughout the design process, our emphasis was in keeping the audio signal in the analogue domain once it leaves the DAC. The HA-1 is anchored by a robust toroidal power transformer with linear power regulators and filters with custom made capacitors to ensure the headphone amplifier has a clean power source with plenty or energy reserves. Users have the choice between using a 4-pin balanced XLR or traditional quarter-inch (6.35 mm) headphone connection.
The power amplification section uses hand-picked and paired discrete components to ensure symmetry. The volume control knob is motor-driven and can be adjusted either by hand or via remote control while keeping the audio in the analogue domain. Line level RCA and balanced XLR analogue inputs and outputs are available, and built-in monitoring and protection circuitry guards against short-circuiting, overloading, and DC offset.
The HA-1 is ideally suited for high-resolution digital audio. It includes coaxial, optical, balanced AES/EBU digital inputs as well as an asynchronous USB DAC controlled by a 16-core XMOS chipset that supports both PCM and DSD formats. The same ESS 9018 Sabre32 Reference DAC and output driving state used in our audiophile Blu-ray players ensures high resolution performance with extremely low noise and distortion. You can easily connect the HA-1 to a computer via USB and enjoy jitter-free music using your preferred playback software. For added convenience, Bluetooth connectivity with the high quality aptX codec is also available.
Aesthetically, the HA-1 features a classic design with contemporary elements. It is housed in a thick aluminium chassis, and its familiar volume and source selection knobs are complemented by a high-quality TFT LCD display providing convenient access to the HA-1’s intuitive user interface. Depending on your preferences or the mood of the music being played, you can choose between a classic VU meter, a modern spectrum display, or a simple informational summary to be displayed on the screen. A supplied IR remote and smartphone application via Bluetooth provide additional control and convenience.
The OPPO HA-1 Headphone Amplifier allows you to fully realize the potential of your high-end headphones. The HA-1 is a perfect match for OPPO Planar Magnetic headphones, and its power and versatility allow it to meet the demands of the most discerning music lover.
Specifications:
Recommended Headphone Impedance: 32 ohm – 600 ohm
Input Impedance: 15k ohm (XLR Balanced); 10k ohm (RCA)
Maximum Input Level: 18 Vrms, +27.3 dBu (XLR Balanced); 9 Vrms, +21.3 dBu (RCA)
Coaxial, Optical, AES/EBU Digital Inputs:
Input Format: Stereo PCM
Sampling Frequencies: 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, 192 kHz
Word Length: 16-bit, 24-bit
USB DAC Audio Input (USB B Type):
Input Format: Stereo PCM, Stereo DSD (DoP v1.1 or native)
PCM Sampling Frequencies: 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, 192 kHz, 352.8 kHz, 384 kHz
PCM Word Length: 16-bit, 24-bit, 32-bit
DSD Sampling Frequencies: 2.8224 MHz (DSD64), 5.6448 MHz (DSD128), 11.2896 MHz (DSD256, native mode only)
Profile: USB 2.0, USB Audio 2.0
Mobile USB Audio Input (USB A Type):
Input Format: Stereo PCM
PCM Sampling Frequencies: 44.1 kHz, 48 kHz
Profile: USB 2.0, USB Audio 2.0
Bluetooth Audio Transmission Format: SBC, aptX
DAC Performance:
Output Level: 4.6 ± 0.3 Vrms (XLR); 2.3 ± 0.3 Vrms (RCA)
Frequency Response: 10 Hz – 170 kHz (+ 0/- 3 dB); 20 Hz – 20 kHz (+ 0/- 0.07 dB)
THD+N at 1 kHz: < 0.00056% (< – 105 dB)
Channel Separation: > 105 dB
Signal-to-Noise Ratio: > 115 dB (XLR); > 113 dB (RCA)
Dynamic Range: > 115 dB (XLR) > 113 dB (RCA)
Pre-amplifier Performance:
Rated Output Level: 4.6 Vrms (XLR); 2.3 Vrms (RCA)
Frequency Response: 10 Hz – 200 kHz (+ 0/- 2 dB), 20 Hz – 20 kHz (+ 0/- 0.04 dB)
THD+N at 1 kHz: < 0.00056% (< -105 dB) (XLR); < 0.00071% (< -103 dB) (RCA)
Channel Separation: > 120 dB (XLR); > 110 dB (RCA)
Signal-to-Noise Ratio: > 110 dB (XLR); > 105 dB (RCA)
Dynamic Range: > 120 dB (XLR); > 115 dB (RCA)
Maximum Gain: 6 dB
Headphone Power Amplifier:
Maximum Output Power: Into 600 Ohm: 2400 mW (XLR); 600 mW (RCA) Into 32 Ohm: 3000 mW (XLR) 3500 mW (RCA)
Rated Output Power: Into 600 Ohm: 800 mW (XLR); 200 mW (RCA) Into 32 Ohm: 2000 mW (XLR) 500 mW (RCA)
Frequency Response at Rated Power: 10 Hz – 200 kHz (+ 0/- 1 dB), 20 Hz – 20 kHz (+ 0/- 0.04 dB)
THD+N at 1 kHz: Rated Power < 0.0018% (< -95 dB) (XLR); < 0.0056% (< -85 dB) (RCA)
Channel Separation: > 120 dB (XLR); > 90 dB (RCA)
Signal-to-Noise Ratio: > 111 dB
Dynamic Range: > 120 dB (XLR); > 115 dB (RCA)
Output Impedance: 0.5 Ohm (XLR); 0.7 Ohm (RCA)
Power Supply: AC 110-120 V~ / 220-240 V~, 50/60 Hz auto-sensing
Power Consumption: 70 W (operation); 0.5 W (standby)
Dimensions: 254 (W) x 80 (H) x 333 (D) mm
Weight: 5.9 kg

To read a review from Hi-Fi Choice magazine please CLICK HERE