The Benchmark HPA4 headphone preamp/amplifier is based on the proprietary line-out amplifier and THX’s THX-888 AAA™ (Achromatic Audio Amplifier) headphone amplifier technology. The same technology is used in the AHB2 power amplifier. This technology achieves exceptional measurement levels with very low noise and distortion with near-perfect linearity. This headphone preamp/amplifier also features high power output, making it compatible with most headphones on the market, regardless of their impedance. The HPA4 uses all-analog circuitry and is therefore designed to work in conjunction with a DAC or external analog source. The front panel features a touch screen for easy access to parameters and settings. In terms of connectors, there are 2 balanced stereo XLR inputs and 2 stereo RCA inputs with stereo RCA and XLR outputs. In addition, there are two 12V 3.5mm trigger jacks, one XLR mono output and two headphone outputs: 6.35mm jack and 4-pin XLR.
THX-888 technology is capable of delivering high voltage and driving high impedance headphones with low sensitivity. The HPA4 delivers up to 11.9V into a 300-ohm load and up to 6W into a 16-ohm load. Given the extreme capabilities of its amplifier, Benchmark has built in protection systems to protect the equipment (DC detection, short circuit detection, overcurrent protection, overvoltage protection and thermal protection).
HPA4 has a bandwidth of 0.1 Hz to 200 kHz. This makes it a preamp/headphone amplifier capable of producing an extremely detailed and accurate signal.
The touch screen on the front of the HPA4 provides easy access to settings such as balance adjustment, input level offset, input names, screen brightness and function lock. The volume control knob is equipped with a high-quality optical encoder and has 256 volume levels with a resolution of 0.5 dB/step. Pressing this volume knob selects the desired output. In addition, the remote control enhances the user’s options.
Benchmark HPA4 specifications:
- Product Type: Preamp/Headphone Amplifier
- Amplification Technology: THX-888 (AAA™) and Low Noise Linear Amplifier
- Inputs: 2x RCA stereo input/2x XLR balanced stereo input
- Outputs: 1x stereo RCA output/1x balanced stereo XLR output/1x mono XLR output/1x 6.35mm headphone output/1x balanced XLR headphone output
- Bandwidth: 0.1 Hz – 500 kHz
- SNR: >135 dB
- THD: 125 dB
- Screen: Touch Screen
- Trigger: 2x 3.5mm jack 12V bidirectional HEADPHONE OUTPUT MEASUREMENTS (+24DBU INPUT) THD: -125 dB (0.00006%)
- SNR: > 135 dB, A-weighted
- Frequency response: -0.003 dB at 10 Hz, -0.001 dB at 20 kHz
- Bandwidth: -3dB exceeds 0.1Hz to 500kHz
- Output impedance: About 0 ohm
- Output Noise: 2.45 µV at unity gain, 20-20 kHz
- Maximum output power: 6 W into 16 ohm load
- Maximum output current: 1.5A
- Maximum output voltage: 11.5 Vrms into 300 ohms
- Crosstalk: -133 dB at 1 kHz, -115 dB at 10 kHz (XLR4) LINE OUT THD MEASUREMENTS: -125 dB (0.00006%)
- SNR: >135 dB unweighted, 20-20 kHz/>137 dB A-weighted
- Frequency response: -0.003 dB to 10 Hz, -0.001 dB to 20 kHz
- Bandwidth: -3 dB over 0.1 Hz à 500 kHz
- Output impedance: 60 ohms
- Output Noise: 1.9 µV at unity gain, 20-20 kHz
- Maximum input and output voltage: 20 Vrms (+28 dBu)
- Crosstalk: -133 dB at 1 kHz, -116 dB at 10 kHz
- Power: 100-240VAC 50/60Hz
- Power Consumption: 18W (typ.)/35W (max.)
- Standby power consumption: 0.33W
- Dimensions: 203.2 x 76.2 x 203.2 mm
- Weight: 3.65 kg
- Color: silver front / black body
