The Oppo HA1 headphone amplifier is a quite astonishing piece of equipment, and just the job for getting the very best out of digital music on your PC, and presenting it to you via your headphones.
Naturally, it is designed to compliment the Oppo PM1 headphones, but principally this means that it has plenty of drive power available, rather than being dedicated to them.
The HA-1 is a high performance headphone amplifier, but it also doubles as an asynchronous USB DAC, a stereo pre-amplifier, a digital audio dock for mobile devices, and a Bluetooth audio transport. Its fully balanced design and numerous inputs ensure the best in fidelity and versatility.
The analogue audio section of the HA-1 is a fully balanced design with an emphasis on keeping the audio signal in the analogue domain once it leaves the DAC. The HA-1 is anchored by a beefy 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 power amplification section uses hand-picked and paired discrete components to ensure symmetry. A motor-driven precision volume control knob enables both hand adjustment and remote control while keeping the audio in a pure analogue audio path. Users have a choice of using the 4-pin balanced XLR or the traditional quarter-inch headphone jack. Line level analogue inputs and outputs are provided with both RCA and balanced XLR sockets. Built-in monitoring and protection circuitry guards against any mishaps such as short-circuiting, overloading, and DC offset that could lead to degraded performance.
The HA-1 is especially suitable for high-resolution digital audio. Its digital inputs include coaxial, optical, balanced AES/EBU, and an asynchronous USB DAC that supports both PCM and DSD formats. The same ESS 9018 Sabre32 Reference DAC and output driving stage used in our audiophile Blu-ray players ensures extremely low noise and low distortion performance. It is easy to connect the HA-1 to a computer via USB and enjoy jitter-free music using your favourite playback software. OPPO is also working with a leading smartphone and tablet manufacturer to certify the HA-1 so it can pass the required authentication and take digital audio from those popular mobile devices. For additional convenience, the Bluetooth audio transport with high quality Apt-X CODEC sets music in your mobile phones free with a performance boost.
What we think:
This is a superb DAC, preamp and headphone amp capable of driving the most demanding and capable headphones. It has a wealth of features, most of which are highly useful, and an entertaining range of display modes for the front panel. Sound-wise, this does not disappoint, with excellent control and space within the music. We love it!
Once more Oppo are so proud of their engineering that they include photographs of the insides (right), and casting our beady eyes over it, there is certainly excellent attention to detail.
It comes with a funky little remote control, though if you’re using it with a computer the chances are that it’ll be sitting on the desk just in front of you.
Oppo have included an AV input volume bypass, so it can be used with a surround amplifier on the front main channels, adding to it’s flexibility.
Specifications
| General | |
| 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, 10 mA 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
| XLR Output | RCA Output |
| Output Level: 4.6 ± 0.3 Vrms | Output Level: 2.3 ± 0.3 Vrms |
| Frequency Response:
10 Hz – 170 kHz (+0/-3 dB) 20 Hz – 20 kHz (+0/-0.07 dB) |
Frequency Response:
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) |
THD+N at 1 kHz (A Weight, 20 Hz – 20 kHz):
< 0.00056% (< -105 dB) |
| Channel Separation:
> 105 dB |
Channel Separation:
> 105 dB |
| Signal-to-Noise Ratio (A Weight, 20 Hz – 20 kHz): | 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 |
Dynamic Range(1 kHz -60 dBFS,
A Weight, 20 Hz – 20 kHz): > 113 dB |
(Test condition: USB DAC input in Home Theatre Bypass mode and the volume knob at Max position.)
Pre-amplifier Performance Specifications
| XLR Input – XLR Output | RCA Input – RCA Output |
| Rated Output Level: 4.6 Vrms | Rated Output Level: 2.3 Vrms |
| Frequency Response:
10 Hz – 200 kHz (+0/-2 dB) 20 Hz – 20 kHz (+0/-0.04 dB) |
Frequency Response:
10 Hz – 200 kHz (+0/-2 dB) 20 Hz – 20 kHz (+0/-0.04 dB) |
| THD+N at 1Khz (A Weight, 20 Hz – 20 kHz):
< 0.00056% (< -105 dB) |
THD+N at 1Khz (A Weight, 20 Hz – 20 kHz):
< 0.00071% (< -103 dB) |
| Channel Separation:
> 120 dB |
Channel Separation:
> 110 dB |
| Signal-to-Noise Ratio
(A Weight, 20 Hz – 20 kHz): > 110 dB |
Signal-to-Noise Ratio
(A Weight, 20 Hz – 20 kHz): > 105 dB |
| Dynamic Range
(1 kHz -60 dB, A Weight, 20 Hz – 20 kHz): > 120 dB |
Dynamic Range
(1 kHz -60 dB, A Weight, 20 Hz – 20 kHz): > 115 dB |
| Maximum Gain (100 mVrms input):
6 dB |
Maximum Gain (100 mVrms input):
6 dB |
(Test condition: Volume knob at Max position and an input signal to drive the output to the rated output level.)
Headphone Power Amplifier Specifications
| XLR Input – Balanced Output | RCA Input – 6.35mm Output |
| Maximum Output Power (Per Channel)
into 600 Ohm: 2400 mW
Maximum Output Power (Per Channel) into 32 Ohm: 3000 mW |
Maximum Output Power (Per Channel)
into 600 Ohm: 600 mW
Maximum Output Power (Per Channel) into 32 Ohm: 3500 mW |
| Rated Output Power (Per Channel)
into 600 Ohm: 800 mW
Rated Output Power (Per Channel) into 32 Ohm: 2000 mW
|
Rated Output Power (Per Channel)
into 600 Ohm: 200 mW
Rated Output Power (Per Channel) into 32 Ohm: 500 mW |
| Frequency Response at Rated Power
10 Hz – 200 kHz (+0/-1 dB) 20 Hz – 20 kHz (+0/-0.04 dB) |
Frequency Response at Rated Power
10 Hz – 200 kHz (+0/-1 dB) 20 Hz – 20 kHz (+0/-0.04 dB) |
| THD+N at 1kHz (A Weight, 20 Hz – 20 kHz)
Rated Power: < 0.0018% (< -95 dB)
THD+N at 1kHz (A Weight, 20 Hz – 20 kHz) 50mW: < 0.001% (< -100 dB) |
THD+N at 1kHz (A Weight, 20 Hz – 20 kHz)
Rated Power: < 0.0056% (< -85 dB)
THD+N at 1kHz (A Weight, 20 Hz – 20 kHz) 50mW: < 0.0022% (< -93dB) |
| Channel Separation:
> 120 dB |
Channel Separation:
> 90 dB |
| Signal-to-Noise Ratio
(A Weight, 20 Hz – 20 kHz): > 111 dB |
Signal-to-Noise Ratio
(A Weight, 20 Hz – 20 kHz): > 111 dB |
| Dynamic Range
(1 kHz -60 dB, A Weight, 20 Hz – 20 kHz): > 120 dB |
Dynamic Range
(1 kHz -60 dB, A Weight, 20 Hz – 20 kHz): > 115 dB |
| Output Impedance:
0.5 Ohm
|
Output Impedance:
0.7 Ohm
|
(Test condition: Volume knob at Max position and an input signal to drive the output with 600 Ohm loads to the rated output power, unless otherwise noted.)