AHB2 - "Conspicuous Only in Its Absence"
"Before she joined Jefferson Airplane, Grace Slick was in a band called The Great Society. They made an LP, Conspicuous Only in Its Absence, the title of which has stuck in my mind ever since I first heard it as a teenager. (The album also contains some killer psychedelic rock riffing, but that’s another story for another time.) That album’s title is a perfect description of how the new Benchmark AHB2 power amplifier fits into a studio monitoring system."
"After upgrading my monitors to Amphion Two18 speakers [Tape Op#108], I decided to look into modern alternatives to my circa-1980s Audio Design Associates (ADA) FET300 power amp. That amp, designed by ADA co-founder Albert Langella, is built like a tank and has served me without fail since I built my studio almost 20 years ago."
"Because they were designed for multi-room systems, Langella’s power amps were capable of handling very low impedance loads and were built into massive all-metal boxes. And in this lies the rub: Al preferred to use bigfans to keep things cool in the boxes."
"Over two decades of working with the ADA amp, I got used to the fan noise, and tuned it out. As far as audio quality, the amp offered very good low-level resolution and plenty of dynamic power. I thought it was the cat’s ass and didn’t even consider swapping it out, until I started reading descriptions and reviews of the Benchmark amp."
"The Benchmark AHB2 amp uses new technology from THX, the folks who bring you “certified” cinema sound systems."
"Benchmark took the THX technology another step by designing the amp to work in a lower-gain mode in a pro- audio setting. This allows for a very low noise-floor, because there is no gain wasted and then attenuated."
"The audio system shouldn’t add any noise. It should run in the background — a silent transmitter of the musical energy. In my listening tests, the Benchmark AHB2 amp did this."
"As soon as I unplugged the ADA amp and swapped in the Benchmark, it was clear how nice it was to hear less fan noise. I cranked up the monitor volume all the way on my Lynx Hilo [Tape Op #90] and confirmed there was zero hiss, hum, and other power line hash. I put my ear right to the speakers — still dead silent."
"So now, just from being in the system, the Benchmark had taken down the room noise (no fans) and lowered the monitor system noise floor from very quiet to silent."
"I then started listening to music and other audio — projects I recently completed plus favorite albums. I did this for several weeks, and I also took the Benchmark upstate and plugged it into my B&W 805 Diamond speakers there."
"In every case, I heard the amp as essentially transparent — a silent transmitter of musical energy."
"What did stand out was a very quick and precise quality to the bass, as if the amp is quicker on the draw than most, when it comes to moving the piston to move the air."
"I’ll describe the AHB2 as the sonic equivalent of a very sharp plasma display — full-featured, well-defined, and natural-looking, as if looking at a real thing instead of a digital image."
"Benchmark also sent me a DAC2 HGC [Tape Op #97] to test drive, and I coupled it with the AHB2 in my big listening room, driving a pair of B&W 808 speakers. This setup replaced a Benchmark DAC1 HDR and an Aragon 8008 amp."
"As happened in the studio, when I swapped the former power amp back in, the sound clouded up a bit, the stereo field narrowed a bit, and I found I wanted to turn the volume knob up a bit because things seemed somewhat muddier. To get back to The Great Society album title, the Benchmark AHB2 was very much conspicuous in its absence. My ears missed it!"
"As far as sound differences between the two Benchmark DACs, I couldn’t hear any on the big speakers in my listening room, but Benchmark claims a number of improvements in the DAC2 HGC."
"For me, the compelling case for switching to the DAC2 HGC is its feature set."
"I liked the feature set on the DAC2 HGC enough to buy it for my big listening room, replacing the DAC1 HDR. I bought the AHB2 power amp for my studio and have started filling the piggy bank to buy one for the big listening room. Paired with the Amphion Two18 speakers in the studio, the AHB2 is half of the new “Dynamic Duo.”"
- Tom Fine, Tape Op
Jim Austin wrote, "The DAC3 was all about depths, in several respects . . . I heard deeper into the music."
The concise conclusion to John Atkinson's Measurements sidebar: "All I can say is 'Wow!'"
In a Follow-Up, Jim Austin wrote of using the Benchmark processor with the same company's AHB2 power amp—a combination of high source output voltage and modest amplifier gain that he describes as "optimal for minimizing noise and distortion"—and reported hearing "richer and more interesting" reproduction of very subtle details.
- Stereophile Magazine
"The benchmark combination offers a full range of equipment that can hardly be topped, leaves nothing to be desired in terms of sound, and meets professional requirements without any ifs or buts."
"The HPA4 has the HIFIMan one hundred percent under control, eliciting neutral timbres, tons of spatial information and crisp dynamics."
"I connected everything the household had to offer in terms of speakers - Spendor S3 / 5, Ayon Seagull / c, Quad ESL57. It goes without saying that the American coped with the dynamic boxes with ease. But even the quads, which have some meanness on the part of their impedance, did not pose a challenge for the amp."
"There are many things that come into play when putting together a hi-fi system, one of which is synergy."
"After the arrival of the Benchmark Media Systems AHB2, I immediately thought of the matching HPA4 that colleagues Jaap and Yung were very pleased with."
"The key question, of course, was whether the HPA4 would really provide an audible improvement."
"Well you bet! The synergy between preamp and power amplifier is nothing short of magical, not to mention the DAC3 B that I got from importer Helios for the occasion."
"Not only a few curtains disappear, the whole window is gone."
- Geoffrey Vanhouwaert, Alpha-Audio