Benchmark HPA4 - Flagship reference
headphone amplifier and preamp.
The HPA4 is Benchmark's newest headphone
amplifier. Featuring THX Achromatic Audio
Amplifier (AAA™) technology.
The HPA4 delivers sonic perfection. Hear the
music without any contamination from electronic
noise or distortion. The HPA4 delivers power,
audio fidelity, speed and accuracy over an utterly
The HPA4 features relay gain control, relay input
selection, and relay muting. The line amplifier
incorporates the finest gold-contact relays
available. The gain control has 256 steps in 0.5 dB
increments. It also features a balance control.
Relay closures are precisely timed to deliver silky-
smooth volume changes. No other relay gain
control offers this level of precision and
performance. The HPA4 includes 4 independent
256-step attenuators: two for the L&R headphone
outputs, and two for the L&R line outputs.
THD < -125 dB (0.00006%)
SNR > 131 dB, unweighted, 20-20 kHz
SNR > 135 dB, A-weighted
Frequency Response - 0.003 dB at 10 Hz, -0.001 dB at 20 kHz
- 3 dB Bandwidth exceeds 0.1 Hz to 500 kHz
Output Impedance, near 0 Ohms
Output Noise < 2.45 uV at Unity Gain, 20-20 kHz
Maximum Output Power, 6 Watts into 16 Ohms
Maximum Output Voltage, 11.5 Vrms into 300 Ohms
Crosstalk < -133 dB @ 1 kHz, -115 dB @ 10 kHz (XLR4)
The HPA4 maintains less than 0.00006% THD, even while delivering
a full 6 W output into a 16-Ohm load.
For customers who wish to use the HPA4 as a refference quality line-level pre-amp without the headphones
amplifier, the Benchmark LA4 will fit the bill. This is a fully specified HPA4 without the THX headphones
amplifier built in.
Benchmark AHB2 Power Amplifier -
The quietist, cleanest audio amplifier on
The AHB2 is the ideal match to the performance
limits of High-Resolution-Audio (HRA) formats.
Benchmark's AHB2 power amplifier delivers
musical details without introducing the masking
effects of amplifier noise and distortion. The
dynamic range of the AHB2 is 132 dB, making it 10
to 30 dB quieter than some of the very best
reference-quality power amplifiers available.
The frequency response of the AHB2 extends
beyond 200 kHz. With the AHB2, you will discover
previously overlooked nuances, dynamics, and
detail in your favorite recordings and experience
the full potential of the latest high-resolution 24-bit
PCM and 1-bit DSD audio formats.
The AHB2 drives difficult speaker phase angles
and low impedances with ease. Stereo loads as
low as 1.4 Ohms can be cleanly driven to full
output levels. Most power amplifiers produce
higher levels of distortion when the load
impedance decreases. In contrast, the feed-
forward error correction system in the AHB2 keeps
the output clean when driving difficult loads. The
AHB2 produces almost no measurable distortion at
any rated load condition.
100 Watts per channel into 8 Ohms, both channels driven
190 Watts per channel into 4 Ohms, both channels driven
380 Watts into 8 Ohms, bridged mono
480 Watts into 6 Ohms, bridged mono
1 kHz, 20 kHz LPF, at full rated output into any rated load
< -119 dB (< 0.00011%), Stereo Mode
< -120 dB (< 0.00010%), Mono Mode
Better than 0.1 Hz to 200 kHz, +0/-3 dB
350 at 20 Hz, 8-Ohms
MAXIMUM AUDIO OUTPUT CURRENT
29 A peak, per channel, both channels driven
Low-Gain = 22 dBu (9.8 Vrms), Gain = 9.2 dB
Mid-Gain = 14.2 dBu (4 Vrms), Gain = 17.0 dB
High-Gain = 8.2 dBu (2 Vrms), Gain = 23 dB
Use Mid-Gain or High-Gain settings for unbalanced inputs
50 k Ohms, normal mode
1 M Ohm, common mode