Benchmark AHB2 Power Amplifier

Benchmark AHB2 PRODUCT FEATURES:

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.
The AHB2's extended frequency response, tight bass control, ultra low noise, and vanishingly low distortion are key parameters contributing to accurate reproduction of high-resolution musical recordings. Experience the full emotion and detail captured in your finest recordings:

THE ALL-IMPORTANT FIRST WATT
In a normal listening environment, a comfortable listening level is usually reached with only a few watts of audio power. With high-efficiency speakers, most of the audio may be delivered at less than one watt. In either case, the 1st few watts of power are some of the most important to the listening experience. Unfortunately, most amplifiers perform poorly in this low-power region. This is the region where the non-musical distortion caused by conventional class-AB push-pull output stages can rise to a high percentage of the audio level. Likewise, the dead-band distortion in a class-D amplifier can be problematic at these low output levels. The AHB2 does not have either of these problems. It behaves like a class-A amplifier in the low-power region. The AHB2 is virtually distortion-free in the critical first few watts.

CLEAN TO THE LAST WATT
Class-A amplifiers often perform poorly at high power levels. Likewise, class-D amplifiers often have slew-rate related distortion problems that show up at higher power levels. Class-AB amplifiers tend to do well at high levels, but usually show a gradual increase in distortion energy as the output increases. In contrast to these conventional designs, the AHB2 remains virtually distortion free to the last watt. 

EXTENDED FREQUENCY RESPONSE
The frequency response of the AHB2 extends beyond 200 kHz, to deliver the ultrasonic detail and fast transients captured by high-resolution recordings. At the other end of the audio spectrum, the low-frequency response extends below 0.1 Hz, for solid well-controlled bass.
The extended frequency response delivers a nearly perfect impulse response, and a nearly perfect phase response, over the entire audio spectrum.

THE AHB2 ELIMINATES THE WEAK LINK
Other than loudspeakers, power amplifiers are usually the weakest link in the audio chain. Until now, high-resolution recording formats and converter technology have rapidly outpaced the development of audio power amplifiers. For example, Benchmark DAC2 D/A converters outperform most high-end power amplifiers by very significant margins.
Most power amplifiers limit system noise performance to the equivalent of a 16 to 18-bit digital system. The differences between 16-bit and 24-bit recordings cannot be experienced if the power amplifier can only deliver 16-bit noise performance. In most audio systems, the details captured by today's high-resolution 24-bit PCM systems are completely lost in a veil of amplifier noise and distortion.
Benchmark set out to build an amplifier that would deliver the full performance of their flagship 24-bit 192-kHz D/A converters. The AHB2 realizes this goal, and it is the first power amplifier that meets or exceeds the performance of the DAC2 D/A converter.

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 these low impedance regions with ease. Loads as low as 2.2 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 prevents any increase in distortion. The AHB2 produces almost no measurable distortion at any rated load condition.

HIGH DAMPING FACTOR
The AHB2 has a high damping factor that augments its extended low-end to deliver solid, well-controlled bass. This high damping factor also keeps the frequency response absolutely flat while driving speakers with large frequency-dependent impedance variations.

HIGH OUTPUT CURRENT
The AHB2 can deliver up to 18 A to each channel simultaneously. This robust drive current easily handles some of the most demanding loudspeakers. The AHB2 stays clean while delivering high current.

DISTORTION IS BELOW AUDIBILITY
The AHB2 will never produce audible distortion, In most playback systems, the distortion produced by the AHB2 will never even reach the 0 dB SPL threshold of hearing. This means that the distortion could not be heard, even if it could be played while the music was muted.

The AHB2 allows you to escape the distortion limitations of classic amplifier topologies and enter the world of high-resolution audio playback.

Benchmark AHB2 TECHNICAL SPECIFICATIONS:

OUTPUT POWER
1 kHz, < 0.0003 % THD+N
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 Bridged Mono into 16 Ohms
380 Watts Bridged Mono into 8 Ohms
480 Watts Bridged Mono into 6 Ohms
All speakers have variations in input impedance. Select loads based on nominal impedances not minimum impedances.

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, inputs shorted
7.1 uV, A-weighted, Stereo Mode
9.8 uV, A-weighted, Mono Mode

NOISE POWER RELATIVE TO 1 WATT
Output noise power, inputs shorted
-115 dB Watts, A-weighted, 16-Ohm Load, Stereo Mode
-112 dB Watts, A-weighted, 16-Ohm Load, Mono Mode
-112 dB Watts, A-weighted, 8-Ohm Load, Stereo Mode
-109 dB Watts, A-weighted, 8-Ohm Load, Mono Mode
-111 dB Watts, A-weighted, 6-Ohm Load, Stereo Mode
-108 dB Watts, A-weighted, 6-Ohm Load, Mono Mode
-109 dB Watts, A-weighted, 4-Ohm Load, Stereo 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
18 A peak, per channel, both channels driven
18 A peak, protection shut-down threshold

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 - XLRM adaptor cables (sold separately).

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
Mute Sequencing
Distortion Detection
Short Circuit Detection
Over Current Detection (18 A peak)
Over Temperature
SOA (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