OPPO HA-1 Headphone Amplifier
OPPO`s HA-1 headphone amplifier is quite
simply the best we`ve ever used, can be
utilised as a 2 channel processor as well
but ideally suited to pair with the award
winning OPPO PM-1 Headphones
OPPO HA-1 Headphone Amplifier – perfect to partner with their PM-1 Planar Magnetic Headphones
Uncompromising Audio built with the latest technology
The analogue audio section of the HA-1 is a fully balanced design with and emphasis and keeping the audio signal in the analogue domain once it leaves the DAC. The HA-1 is anchored by a hefty toroidal power transformer, and 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, and 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.
High Performance Audio
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. 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.
OPPO designs the HA-1 headphone amplifier with the same versatile approach as the Blu-ray players. The HA-1 is a high performance headphone amplifier, and it doubles as an asynchronous USB DAC, a stereo pre-amplifier, a digital audio dock for mobile devices, and a Bluetooth audio transport. Users have a choice of using the 4-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 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.
Discrete Class A Amplifier – A Class A amplifier conducts signal over the entire range of the input signal cycle.
The output transistors are biased to operate in their most linear rangeand there is no crossover distortion caused by switching the signal
between two push-pull devices. The HA-1’s power amplification circuit for the headphones is Class A built with discrete transistors.
The discrete design allows us to hand-pick and match the best parts to build the HA-1.
Fully Balanced Design – The internal analog audio signal path of the HA-1
is fully balanced. 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.
Clean Signal Path – The HA-1 uses an analog potentiometer (the familar 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.
Specifications – Designs and specifications are subject to change without notice.
Dimensions (W x H x D) 10.0 x 3.1 x 13.1 inches, 254 x 80 x 333 mm Mass 13.0 lbs, 5.9 kg
Power Supply AC 110-120 V~ / 220-240 V~, 50/60 Hz auto-sensing Power Consumption 70 W (operation), 0.5 W (standby)
Trigger Input 3.5 V – 15 V, 10mA minimum Trigger Output 12 V, 100 mA maximum
Operating Temperature 41 °F – 95 °F, 5 °C – 35 °C Operating Humidity 15% – 75% No condensation
Recommended Headphone Impedance 32 ohm – 600 ohm
Balanced Headphone Jack Output (XLR-4) Pin order 1: L+, 2: L-, 3: R+, 4: R-, Shell: GND 6.35 mm Headphone Jack Output Pin order Tip: L, Ring: R, Sleeve: GND
XLR Balanced Audio Input Input Impedance 15k ohm Maximum Input Level 18 Vrms, +27.3 dBu (0 dBu = 0.775 Vrms)
RCA Stereo Audio Input Input Impedance 10k ohm
Maximum Input Level 9 Vrms, +21.3 dBu (0 dBu = 0.775 Vrms) 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 VBUS Power Output +5 V, 2.1 A
Bluetooth Audio Input Standard Bluetooth 2.1+EDR Profile iAP, SPP, AVRCP, A2DP Audio Transmission Format SBC, aptX
DAC Performance Specifications
Specification XLR Output RCA Output Output Level 4.6 ± 0.3 Vrms 2.3 ± 0.3 Vrms
Frequency Response (Tested with -10 dBFS / 384 kHz) 10 Hz – 170 kHz (+0/-3 dB) 20 Hz – 20 kHz (+0/-0.07 dB) 10 Hz – 170 kHz (+0/-3 dB) 20 Hz – 20 kHz (+0/-0.07 dB)
THD+N at 1 kHz (A Weight, 20 Hz – 20 kHz) < 0.00056% (< -105 dB) < 0.00056% (< -105 dB) Channel Separation > 105 dB > 105 dB Signal-to-Noise Ratio (A Weight, 20 Hz – 20 kHz) > 115 dB > 113 dB
Dynamic Range (1 kHz -60 dBFS, A Weight, 20 Hz – 20 kHz) > 115 dB > 113 db (Test condition: USB DAC input in Home Theater Bypass mode and the volume knob at Max position.)
Pre-amplifier Performance Specifications
Specification XLR Input – XLR Output RCA Input – RCA Output Rated Output Level 4.6 Vrms 2.3 Vrms
Frequency Response 10 Hz – 200 kHz (+0/-2 dB) 20 Hz – 20 kHz (+0/-0.04 dB) 10 Hz – 200 kHz (+0/-2 dB) 20 Hz – 20 kHz (+0/-0.04 dB)
THD+N at 1 kHz (A Weight, 20 Hz – 20 kHz) < 0.00056% (< -105 dB) < 0.00071% (< -103 dB)
Channel Separation > 120 dB > 110 dB Signal-to-Noise Ratio (A Weight, 20 Hz – 20 kHz) > 110 dB > 105 dB
Dynamic Range (1 kHz -60 dB, A Weight, 20 Hz – 20 kHz) > 120 dB > 115 dB
Maximum Gain (100 mVrms input) 6 dB 6 dB
(Test condition: Volume knob at Max position and an input signal to drive the output to the rated output level.)
Headphone Amplifier Performance Specifications
Specification Condition XLR Input – Balanced Output RCA Input – 6.35 mm Output
Maximum Output Power (Per Channel) Into 600 Ohm 2400 mW 600 mW
Into 32 Ohm 3000 mW 3500 mW
Rated Output Power
(Per Channel) Into 600 Ohm 800 mW 200 mW
Into 32 Ohm 2000 mW 500 mW
Frequency Response 10 Hz – 200 kHz (+0/-1 dB) 10 Hz – 200 kHz (+0/-1 dB
20 Hz – 20 kHz (+0/-0.04 dB) 20 Hz – 20 kHz (+0/-0.04 dB)
THD+N at 1k Hz
(A Weight, 20 Hz – 20 kHz) Rated Power < 0.0018% (< -95 dB) < 0.0056% (< -85 dB)
50 mW < 0.001% (< -100 dB) < 0.0022% (< -93dB)
Channel Separation > 120 dB > 90 dB
(A Weight, 20 Hz – 20 kHz) > 111 dB > 111 dB
(1 kHz -60 dB, A Weight, 20 Hz – 20 kHz) > 120 dB > 115 dB
Output Impedance 0.5 ohm 0.7 ohm
HA-1 Headphone Amplifier