Benchmark AHB2 energy amplifier analysis | – StereoNET Australia
Rafael Todes tries this pro audio power amplifier both in the studio and at home …
Benchmark media systems
AHB2 power amplifier
AUD $ 5,199 MSRP
In the neighboring area of pro audio, there is an interesting parallel universe to discover – after all, engineers should want the same thing as audiophiles, namely great sound. Admittedly, due to the strict duration of use and often of transport, they also require greater reliability and robustness. However, for some strange reason, very few products bridge that gap – the two will never meet, it often turns out.
Companies like dCS and Chord Electronics come to mind as exceptions to this rule, but for digital converters this may be an easier task as it doesn’t ask them to power banks of studio monitors or PA speakers directly. As for the latter, B&W has been known to build roads to the great Temple of the Reception, Abbey Road, and quad electrostatics are sometimes found in sound engineer vans. However, amplifiers are less likely to bridge the huge gap.
Based on my experience as a professional musician who regularly performs and / or records live, I cannot imagine many amplifiers with dual HiFi and Pro functionality. Maybe Bryston and one or the other ATC, but there isn’t much. However, we can add Benchmark to this selection list. I heard about this brand for the first time over a decade ago when they produced a DAC that was excellent and affordable for the time. Based in Syracuse, New York, the company was founded 30 years ago by Allen H. Burdick, who recently passed away. His initials adorn the AHB2 power amplifier you see here.
Two things strike you at first glance – it’s surprisingly compact and has the features that make it better at home in a studio than in a lounge area in the listening room. You can bypass the AHB2 to make it a monoblock, or connect it to a single speaker. Only balanced connections are made and there is a choice of gains to suit the speaker. You get regular speaker tie posts as well as a pair of Neutron Speakon connectors on the output side. The front panel has a power switch and a light indicator that can be decoded using the manual. The amplifier will run a series of self-tests at start-up and the various indicators will illuminate to indicate current warnings, overloads, temperature problems, or power loss.
It runs very cool all the time and still offers a stated 100 W rms value at 8 ohms, both channels are driven, and almost twice as much as 4. It’s an interesting design that was developed together with THX. The company says the AHB2 shows no trace of crossover distortion and delivers overall harmonic distortion of less than 0.00011% when in stereo mode – which is extremely low when in doubt. It uses a switching power supply – which explains its light weight of 6kg and small size – and runs in Class H with a novel Class AB output stage and multiple power rails to improve efficiency.
I usually like to leave an amplifier on for a few days before I even get involved with what it’s doing. In the case of the benchmark, however, it turns off after 45 minutes of inactivity. It’s just as good that the manufacturer says it doesn’t take a lot of warm-up to fully play the song. The AHB2 was properly installed in my reference system and consisted of a Townshend Allegri Reference preamplifier with fully balanced inputs and outputs and a dCS Bartok streaming DAC. I initially gave the amp my pair of B&W 802D3s to play with, suitably enough a speaker cousin to be found at Abbey Road Studios, right next to me.
I often use a PS Audio PS10 line regenerator because in some cases it changes the sound of my reference system massively. When I started the AHB2 for the first time without it, the soundstage was surprisingly two-dimensional. I live in central London where there are a lot of noisy networks and I found the benchmark to show this without a doubt. By connecting it to the PS10, the sound stage was brought back to something that I am used to from my reference VAC PHi 200 valve monoblocks.
Set up correctly, I was impressed with its creamy character; There’s no audible distortion you’re talking about, and you get a rounded and smooth sound. Perhaps surprisingly for a pro audio product, it was pleasant and fairly detailed, but in no way the kind of analytical character I was expecting. Rather, I liked the evenness and general consideration of the sound; it was grown up and polite with no artificial edge.
For example with a current recording of Ostrich Heldenleben with Vasily Petrenko and the Oslo Philharmonic, things were pleasant and almost rich in sound. There was a lot of strength and space and a generally broad-shouldered and courageous sound. However, compared to my reference tube design, the color palette was more limited. The AHB2 just made everything feel a little warm, and the texture of the instruments wasn’t that resolved. The wonderful range of hues that make up a full-size symphony orchestra just wasn’t there, but I could see how the benchmark would work in a studio. Wherever you want to find details and flaws, this tone balance is just the thing.
I then moved it up to my other system where I’ve been running a number of classic monitors lately – Yamaha NS-1000Ms, Quad ESL63s, and a recently acquired pair of Rogers LS3 / 5as. These were powered by a classic Marantz 8b tube power amplifier – and as luck would have it, it was made in New York in 1961, fifty-two years before the ABH2 was made in almost the same location! Interestingly, I found that the benchmark power amp worked better in this configuration. its obvious strengths could more easily show through.
There was a noticeable improvement in driving the NS-1000M over the B&Ws. This amp had enough power and grip to get the yams working, and its more insightful mid-range helped widen the range of timbres I liked could hear while painting. I could still tell that it had a certain “studio” style to the way music is made, but many will consider that a strength. Listen to Simon Rattle making a high resolution recording of Haydn’s 88th Symphony, I enjoyed the phrasing of the slow opening; The music was well organized, neat and tidy in front of me with a sense of poise and control. This is not a bubbly, emotional performer; Instead, it brought a more no-nonsense style to the process – exactly what you’d expect from pro equipment.
When driving the quad electrostatics, things were even more impressive. These speakers can be a difficult task, but the AHB2 just shrugged, apparently not in the least bothered by what it was doing. I found the sound strong and grounded; The bass was tight and controlled with good grip, and the mid-range was crisp and clean, with lots of detailed information that a sound engineer would find helpful. Play power plant Tour de France, I was pleasantly surprised by the sound stage which is of course an electrostatic quad strength. Things sounded more haunting and three-dimensional than one might expect from electronic music like this, even though it’s beautiful. It’s not the most roomy amp I’ve heard in terms of stage depth, but it’s still excellent for the price.
Reviewing the AHB2 was interesting to me as it reminded me of how quirky and eccentric my own hi-fi systems have gotten. As the name suggests, the benchmark is more of an all-rounder that tries and manages to do a lot very well. It’s a great leveler because if I’ve played classic rock SEM in the form of welcome to the crew or a Debussy At the beginning it had a consistent, even, orderly and mature sound, which was supported by many skills for driving with loudspeaker load. Like any good studio equipment, it should focus more on the mechanics of the music than on the intricacies of the piece. That fits the territory …
Thumbs up for this compact, versatile, well-designed, well-built stereo power amplifier. Benchmark’s AHB2 is a top notch act that delivers a lot for its price. It can also be used as a great all-round stereo power amplifier in someone’s home when it’s not being hammered by a disheveled studio engineer. I record orchestral and chamber music, so I am very aware of their abilities in one way or another.