AHB2 Review - Paul Seydor, The Absolute Sound

May 13, 2016

AHB2 Review - Paul Seydor, The Absolute Sound

AHB2 - "Essentially Perfect"

"Benchmark products ... are made for the professional market (where they are ubiquitous) and designed to the most exacting standards of performance and reliability."

"Within a remarkably short period of time ... my mental processes shifted from comparison mode to enjoying music, all the attention drawn to the source material and the rare sensation of feeling as if I were listening back to the source."

Resolution

"The Benchmark resolves and thus reproduces all the detail there is on every recording I played that I know well."

"Let me cite the toughest resolution test I know: for the a capella introduction of “Moon River” on her Johnny Mercer album, the soprano Jacintha was placed in an isolation booth while occasional chords from a piano were played through her headphones so that she could stay in tune. Despite heroic measures to ensure isolation, the chords nevertheless bled through her headphones and can be heard during the silences. Now these are extremely far down in level; in a couple of instances they are all but inaudible. If a component can reproduce them, that’s about as much resolution as you are ever likely to need. Suffice it to say the Benchmark did."

Neutral Sound

"The Benchmark will reproduce a bright, forward sound if it’s in the source, as it is with a vengeance in Bernstein’s New York recording of Copland’s Appalachian Spring, and it will produce a warm and intimate sound if that is in the source, as in Ofra Harnoy’s Arpeggione sonata by Schubert."

"The Big Stuff"

What about the big stuff? Well, I don’t know much bigger stuff than the lowest organ notes on Kei Kioto’s Bach recital, and they’re not transients, either but deep, long sustained notes. No problem on the Quads or the Super HL5plus."

"Benjamin Zander’s recording of the Mahler Sixth with its hammerblows was awesome enough in slam and weight to satisfy. If you need more power, you can always add a second AHB2 and bridge both for mono operation."

"As part of the evaluation, I auditioned a single AHB2 driving the Harbeths in a room considerably larger than my own: 18 feet wide by 32 feet long with a pitched ceiling that rises to 13 feet at its apex. This combination filled the room as loud as I and the owner could stand and at no point did the clipping indicators illuminate, even during loud organ music with sustained very low notes."

Accuracy and Reliability

"Because accuracy allied to absolutely reliable performance is the goal of all the Benchmarks."

"... a precision instrument designed to perform the precisely defined task of reproducing music and sound accurately, which it does essentially to perfection."

"Professionals buy Benchmark because they know the products work and are reliable and accurate—indeed, reference caliber. Music lovers buy them because they are neutral and accurate and thus reproduce the tonal character of voices and instruments correctly."

"... they are not products that tend to attract cults or other sorts of starry-eyed enthusiasts, wholly lacking any of the quirks, foibles, idiosyncrasies, sonic flavorings, euphonic distortions, and so on that characterize the objects of most audio cults. But to anyone else ..."

"... the AHB2 gets as high, enthusiastic, and confident a thumbs up as my arm is capable of reaching."

- Paul Seydor, The Absolute Sound, April 2016

Read the review →



Also in Reviews

HPA4 - Lab Report - Paul Miller, Hi-Fi News
HPA4 - Lab Report - Paul Miller, Hi-Fi News

October 09, 2018

"Here's a brand that's aptly named - its products providing a 'benchmark' technical performance. The HPA4 is no exception with its relay-switched stepwise volume attenuator calibrated in 0.5 dB steps over a 'useable' 105 dB range."

"Distortion and noise are vanishingly low."

"The frequency response is ruler flat (+/- 0.01 dB) from 1 Hz - 100 kHz."

"The [line output] source impedance is a sensible 30 Ohms and the maximum output a huge 22 V."

"Via the headphone amp, the maximum voltage is 11.2 V and ... the maximum power output is a substantial 4.4W/25ohm and 7.7W/8ohm."

"So, not only will the HPA4 drive the toughest headphone loads but its ... insignificant -102 dBV (8uV) residual noise also ensures exceptionally quiet backgrounds when listening with the most sensitive headphones/earbuds."

"Distortion is broadly unaffected by loading."

"The source impedance is a low <0.6 Ohms up to 10 kHz, increasing to 0.78 Ohms at 20 kHz."

- Paul Miller, Hi-Fi News
Read More
HPA4 Review - Andrew Everard, Hi-Fi News
HPA4 Review - Andrew Everard, Hi-Fi News

October 09, 2018

Hi-Fi News "Outstanding Product" Award

"Benchmark describes its product as a 'reference Stereo Headphone Amplifier and Reference Line Amplifier with Relay Gain and Input Control', which should give you some idea of what's going on here, but only hints at the fact that this is actually two completely separate products packed into one relatively compact unit."

"The headphone section is powered by a power amp from THX, employing the same AAA (Achromatic Audio Amplifier) technology first used by the company in its AHB2."

"Benchmark's line amplifier uses relays for input selection, gain control and muting while four independent 256-step attenuators ... feed the the headphone ... and preamp outputs."

"As PM notes in his Lab Report, this design gives the HPA4 not only outstanding performance, but also rather impressive - to say the least - signal delivery."

"All of a track or two should do the trick, as whether with revealing headphones ... or used as a preamp, the HPA4 simply drops jaws with the sheer impact, openness and vivacity of the way it plays music."

"It was one of those real 'performer in the room' experiences and I was instantly transported back to the time I spent monitoring the recording as it was being made ..."

 - Andrew Everard, Hi-Fi News, November 2018

Read More
DAC3 & AHB2 System - Jim Austin, Stereophile
DAC3 & AHB2 System - Jim Austin, Stereophile

October 02, 2018

"Noise, Resolution & Benchmark"

"John Atkinson's measurements corroborated Benchmark's claim that the DAC3 is capable of "at least" 21-bit performance ..." 

"Benchmark created an amplifier that more than matched the DAC3's dynamic range: the AHB2. Bridged to mono, the AHB2 has a claimed A-weighted dynamic range of 135dB ... it now sits in Class A of Stereophile's 'Recommended Components.'"

"With the DAC3 HGC and the AHB2, Benchmark seems to have achieved the lowest-noise, lowest-distortion system of source and amplification on the planet. The signals this combo sends to loudspeakers should be cleaner—truer to the source—than any other audio components can achieve."

"This article is unusual ..."

"This article is unusual in that my goal was not to take the measure of a particular component but to determine whether Benchmark's entire low-noise system could resolve musical detail that a more typical audiophile system, with noise and distortion levels that are low but not as low, could not."

"The comparison system consisted of PS Audio DirectStream DAC and BHK Signature preamp and, variously, PS Audio BHK 300 and Pass Laboratories XA60.8 monoblocks."

"Through the Benchmark amps those quiet sounds were richer and more interesting. There seemed to be more going on in those quiet moments. It's harder to describe than it was to hear."

"Over the course of several days, I went back and forth between the Benchmark amplifiers and heard it every time. The difference didn't go away."

- Jim Austin, Stereophile

Read More