Benchmark AHB2 Power Amplifier

THE QUIETEST, CLEANEST AUDIO AMPLIFIER ON THE PLANET

From the first watt to the last watt, no audio power amplifier offers lower noise or lower distortion than the Benchmark AHB2.Benchmark has raised the bar by introducing a new and revolutionary amplifier!

-Bascom King, BHK Labs

“If ever there were a giant-killer of an amp, this is it.”

- Hans Wetzel, SoundStage!

- John Atkinson, Stereophile

TRUE HIGH-RESOLUTION PERFORMANCE 

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.

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.

EXPERIENCE THE EMOTION

The musical details and emotion captured on today's finest High-Resolution-Audio recordings can only be fully appreciated when every component in the signal chain is capable of true high-resolution performance. Power amplifiers are a weak link in most audio systems. Most power amplifiers are well matched to the limitations of the CD format, but they fall well short of the capabilities of high-resolution formats. In contrast, the revolutionary AHB2 was specifically designed to deliver true high-resolution performance.

- Ben Shyman, Home Theater Review

FULFILLING THE NEED FOR BETTER AMPLIFICATION

D/A conversion technology has outpaced the development of new power amplifiers. This means that the power amplifier has become a limiting factor in many audio systems. For example, the noise and distortion produced by the Benchmark DAC3 D/A converter is 20 to 30 dB lower than that produced by most high-quality power amplifiers. Until now, this meant that the DAC3 could not be fully appreciated. Benchmark set out to solve this problem by creating an amplifier that matches the performance of the DAC3.

A RADICALLY DIFFERENT POWER AMPLIFIER

We had to look beyond existing amplifier technologies and explore some new and radical solutions. In our search, we learned of two new patents on a new amplifier technology from THX. This was exactly the technology we needed to build our new amplifier.

The AHB2 uses the new and revolutionary THX-patented AAA™ technology to virtually eliminate all forms of distortion. This technology uses feed-forward error correction to eliminate the distortion that is normally produced by the output stage.  No other audio amplifier comes close to delivering the clean, quiet, and robust power of the AHB2.

DIFFICULT SPEAKER LOADS ARE HANDLED WITH EASE

Many loudspeakers have frequencies at which their impedance drops to levels that are much lower than the "nominal" impedance. The AHB2 drives difficult 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.

In our quest to build the ultimate amplifier, we also focused on frequency response, output noise, drive current, damping factor, and reliability. The result is an amplifier that stands head and shoulders above the competition.

DESIGNED, ASSEMBLED, AND TESTED IN THE USA

This Benchmark product was designed, assembled, and tested in the USA using USA and imported components. Most major components are made in USA.

Technical Specifications

CONTINUOUS AVERAGE OUTPUT POWER

< 0.0003 % THD+N at full rated power, 20 Hz to 20 kHz

• 100 Watts per channel into 8 Ohms, both channels driven
• 130 Watts per channel into 6 Ohms, both channels driven
• 190 Watts per channel into 4 Ohms, both channels driven
• 240 Watts per channel into 3 Ohms, both channels driven
• 200 Watts into 16 Ohms, bridged mono
• 380 Watts into 8 Ohms, bridged mono
• 480 Watts into 6 Ohms, bridged mono

All speakers have variations in input impedance. Select loads based on nominal impedances not minimum impedances. The AHB2 is stable into all loads. The AHB2 is conservatively rated at an output level where THD+N is < 0.0003 % instead of the more typical 1% THD+N. Power at 1% THD will be higher.

OUTPUT VOLTAGE INTO VARIOUS LOAD IMPEDANCES

< 0.0003 % THD+N at the following output voltages and load impedances, 20 Hz to 20 kHz

• 29.03 dBV, 31.25 dBu, 28.28 Vrms into 8 Ohms, both channels driven
• 28.92 dBV, 31.14 dBu, 27.93 Vrms into 6 Ohms, both channels driven
• 28.81 dBV, 31.03 dBu, 27.57 Vrms into 4 Ohms, both channels driven
• 28.57 dBV, 30.79 dBu, 26.83 Vrms into 3 Ohms, both channels driven
• 27.14 dBV, 29.36 dBu, 22.76 Vrms into 2 Ohms, both channels driven
• 35.05 dBV, 37.27 dBu, 56.57 Vrms into 16 Ohms, bridged mono
• 34.83 dBV, 37.05 dBu, 55.14 Vrms into 8 Ohms, bridged mono
• 34.59 dBV, 36.81 dBu, 53.67 Vrms into 6 Ohms, bridged mono
• 33.16 dBV, 35.38 dBu, 45.52 Vrms into 4 Ohms, bridged mono

Use dBV to calculate the peak SPL from your speaker/amplifier combination. Use the following formula: Amplifier output voltage in dBV + speaker sensitivity at 2.83V - 9 dB. Example: (29.03 dBV at 8 Ohms) + (90 dB SPL @ 2.83V 1m) - 9 dB = 110 dB SPL at 1 meter

SNR & DYNAMIC RANGE

Rated output relative to output noise, inputs shorted

• 132 dB A-weighted, Stereo Mode
• 135 dB A-weighted, Mono Mode
• 130 dB Unweighted, 20 Hz to 20 kHz, Stereo Mode
• 133 dB Unweighted, 20 Hz to 20 kHz, Mono Mode

NOISE VOLTAGE

Output noise voltage, A-weighted, inputs shorted

• -103 dBV, -101 dBu, 7.1 uVrms, Stereo Mode
• -100 dBV, -98 dBu, 9.8 uVrms, Mono Mode

Use dBV to calculate the SPL of the noise produced by your speaker/amplifier combination. Use the following formula: Amplifier output noise voltage in dBV + speaker sensitivity at 2.83V - 9 dB. Example: Mono mode driving very high efficiency speakers: (-100 dBV) + (104 dB SPL @ 2.83V 1m) - 9 dB = -5 dB SPL at 1 meter. This means that the system noise will be 5 dB below the threshold of hearing when driving speakers with a very high 104 dB efficiency.

NOISE RELATIVE TO 2.83 VRMS

Output noise relative to 2.83 Vrms, A-weighted, inputs shorted

• -112 dB, Stereo Mode
• -109 dB, Mono Mode

THD+N

1 kHz, 80 kHz LPF, at full rated output into any rated load

• < -118 dB (< 0.00013%), Stereo Mode
• < -118 dB (< 0.00013%), Mono Mode

THD

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

CROSSTALK

• Better than -115 dB at 1 kHz
• Better than -92 dB at 20 kHz

FREQUENCY RESPONSE

• Better than 0.1 Hz to 200 kHz, +0/-3 dB
• -0.01 dB at 20 Hz, -0.17 dB at 20 kHz, 8-Ohm Load
• -0.23 dB at 20 Hz, -0.32 dB at 20 kHz, 4-Ohm Load

DAMPING FACTOR

• 350 at 20 Hz, 8-Ohms
• 254 at 1 kHz, 8-Ohms
• 34 at 20 kHz, 8-Ohms
• 7 at 200 kHz, 8-Ohms 

MAXIMUM AUDIO OUTPUT CURRENT

• 29 A peak, per channel, both channels driven

INPUT SENSITIVITY

• 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
• Unbalanced inputs require RCA to XLRM adapter cables 

INPUT IMPEDANCE

• 50 k Ohms, normal mode
• 1 M Ohm, common mode

INPUT CMRR

• 80 dB at 20 Hz, typical
• 80 dB at 1 kHz, typical
• 65 dB at 20 kHz, typical

TRIGGER I/O

• 12 VDC 200 mA current-limited output to trigger turn-on of remote devices
• DC input for slaving to remote devices
• Input responds to 3.3 V logic and higher, VIL = 1.26 V, VIH = 2.7 V
• Absolute maximum input voltage = 30 VDC
• Absolute minimum input voltage = -0.3 VDC
• Input Impedance = 20 k Ohms

PROTECTION CIRCUITS

• Fully Electronic, No Relays
• Mute Sequencing
• Distortion Detection
• Short Circuit Detection
• Over Current Detection
• Over Temperature Detection
• SOA Detection (Output device safe operating area)

DIMENSIONS

NON-RACK-MOUNT VERSION:

• 11.04" W x 3.88" H x 9.34 " D - Including feet and binding posts
• 11.04" W x 3.47" H x 8.33 " D - Excluding feet and connectors
• Faceplate height is 2RU

RACK-MOUNT VERSION:

• 19.00" W x 3.88" H x 10.62 " D - Including binding posts, handles and removable feet
• 19.00" W x 3.47" H x 8.33 " D - Excluding feet and connectors
• 9.09" rack depth, including binding posts, excluding cables
• 11" rack depth, including cables
• Faceplate height is 2RU

WEIGHT

• 12.5 lbs., 16 lbs. shipping - Non-rack-mount version
• 13.5 lbs., 17 lbs. shipping - Rack-mount version

AC INPUT

• Auto-ranging AC Input
• 100 to 120 VAC +/- 10%, 8 Amps, 50 - 60 Hz
• 220 to 240 VAC +/- 10%, 8 Amps, 50 - 60 Hz
• Idle Power Consumption = 20 W
• Standby Power Consumption < 0.5 W