Benchmark AHB2 Review (Updated Measurements)

[restorer-john]

I’m getting constant popping from my AHB2 out of nowhere. It was working fine one day connecting via XLR to the source and bananas to my towers. The next day, nothing but popping, even if the source is turned to 0…

Contact Benchmark directly. Send them an audio recording of the issue, with no connection to the amp except the loudspeakers.

In my experience, they are incredibly fast in responding to issues.

 

[Ovo23]

Did Benchmark show their products on axpona? If so, did they reveal any new product ? The latest was almost 5 years ago, while the amplifier ahb2 is more than a decade. I am really looking forward that they can make an amp of 200+w and improve the bridged mode so that it is not only double the power but stable. Besides, I also hope they can create an integrated amplifier. I haven't seen any amplifier in A/B design doing better while spending less than Benchmark and they actually explain every single step they take and how it improved. Even better, I hope I can see it handle even below 2ohm and stable..

 

[fredoamigo]

Did Benchmark show their products on axpona? If so, did they reveal any new product ? The latest was almost 5 years ago, while the amplifier ahb2 is more than a decade. I am really looking forward that they can make an amp of 200+w and improve the bridged mode so that it is not only double the power but stable. Besides, I also hope they can create an integrated amplifier. I haven't seen any amplifier in A/B design doing better while spending less than Benchmark and they actually explain every single step they take and how it improved. Even better, I hope I can see it handle even below 2ohm and stable..

Although very popular with audiophiles, Benchmark is a company with a professional (public) vocation and I don't think that an integrated amp is useful in the pro market.
On the other hand, I find it difficult to improve a product that is already perfect for most users.

 

[etc6849]

Just add an HPA4 if you want integrated amp functionality? They are designed to work very well together.

Besides, I also hope they can create an integrated amplifier.

 

[livinon2wheels]

I use locking ones.

Here are the Specifications for the Amplifier. As expected they are detailed and lengthy:

Manufacturer 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

so what is the damping factor at 4 ohms?

 

[pogo]

See here, not bridged: Link

 

[RichB]

so what is the damping factor at 4 ohms?

Here are the Benchmark specs:

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

Take these and divide by 2.

- Rich

 

[Julf]

so what is the damping factor at 4 ohms?

"More than enough".