Benchmark AHB2 Power Amplifier - Black - 19 Inch Rackmount

The Quietest Amplifier You Will Hear

The AHB2 is the quietest power amplifier most people will ever hear, and that is the entire point of it. Benchmark built it around THX's Achromatic Audio Amplifier technology, in which a low-power feed-forward amplifier drives a low-bias Class AB output section.

It makes 100 watts per channel into 8 ohms, 190 into 4 and 259 into 2, with both channels driven throughout. Bridge a pair to mono and each makes 380 watts into 8 ohms, or 518 into 4.

The chassis is 11 inches wide and weighs 12.5 pounds, which is startling for the output. There is no fan, and it does not run hot, because a feed-forward design wastes very little as heat.

Inside the Chassis

The distortion figure is the headline: THD+N below 0.00013% at full rated output. Signal-to-noise reaches 132dB A-weighted in stereo and 135dB in mono, and dynamic range is 130dB unweighted across the audible band.

Those are not marketing numbers. They are the reason listeners report hearing detail in familiar recordings they had never noticed before. The amplifier is simply not adding anything on top of what the record already holds.

Frequency response runs from 0.1Hz to 200kHz. Damping factor is 350 at 20Hz into 8 ohms. Two balanced XLR inputs are fitted at 50k ohms, with three gain settings — 9.2dB, 17.0dB and 23dB — so the amplifier can be matched to a professional source or a domestic preamplifier.

What Reviewers Are Saying

Stereophile lists the AHB2 in its Recommended Components, 2026 edition, marked both as a value recommendation and as a long-term reference. It is "Named for the late Allen H. Burdick, the engineer whose work formed the basis for its design".

Kalman Rubinson found the practical result in his listening: "much more apparent low-level detail in already-familiar recordings", which Stereophile credits to "the Benchmark's evident noiselessness".

Who Is This Amplifier Best For?

• You want to hear the recording, not the amplifier — THD+N below 0.00013% and a 132dB noise figure mean what reaches your speakers is what was on the record, which is the whole argument for this amplifier.
• Your speakers drop to low impedance — 259 watts per channel into 2 ohms, both channels driven, is a figure most amplifiers of this size cannot approach.
• Space or heat is a constraint — 11 inches wide, 12.5 pounds, no fan and very little waste heat, so it fits and behaves where a conventional Class AB amplifier of this ability would not.
• Your system may grow to monoblocks — bridged, each AHB2 makes 380 watts into 8 ohms, so a second unit doubles the system rather than replacing the first.
• You run a preamp or a streamer/DAC with its own volume — that is where the controls sit; see our preamplifiers

How Does It Connect to Your System?

Connect your preamplifier to the balanced XLR inputs, and set the gain switch to suit it so your volume control lands in a comfortable range. Speakers go to the binding posts.

Register the amplifier with Benchmark when it arrives. That single step takes the warranty from one year to five in the US, and it costs nothing.

Pairs Well With

Here are some great companions:

• Preamplifier: Required, and the natural next decision — see our Preamplifiers.
• Speaker Cables: Carry the current properly — see our Speaker Cables.
• Interconnects: Balanced XLR is what this amplifier wants — see our Interconnect Cables.
• Audio Rack: Give the amplifier a proper shelf — see our Audio Racks.

Frequently Asked Questions

How much power does it make?

100 watts per channel into 8 ohms, 190 into 4 and 259 into 2, both channels driven. Bridged to mono it makes 380 watts into 8 ohms and 518 into 4.

Why does the distortion figure matter?

At below 0.00013% THD+N the amplifier adds essentially nothing to the signal. That is what listeners mean when they report hearing detail in records they know well.

What are the three gain settings for?

9.2dB, 17.0dB and 23dB. They let you match the amplifier to a professional source or a domestic preamplifier so the volume control sits in a usable range.

Does it have RCA inputs?

Two balanced XLR inputs are fitted, at 50k ohms. Benchmark's gain settings are matched to both balanced XLR and unbalanced RCA signal levels — call us on 800-942-0220 and we will sort out what your preamplifier needs.

Can I use two as monoblocks?

Yes. Bridged to mono each AHB2 makes 380 watts into 8 ohms, 518 into 4 and 200 into 16.

What warranty does it carry?

One year as standard, which Benchmark extends to five years in the US simply by registering the amplifier. Register it when it arrives.

See It in Action

Benchmark Media Systems explains running the AHB2 bridged or in stereo:

Z Reviews puts the AHB2 through a full review:

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Learn More

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