AHB2 Review - Sandu Vitalie, Sound News
AHB2 - "I Purchased Two Units With My Hard-Earned Money"
"The highest compliment I can give to AHB2 is that I purchased not one, but two units with my hard-earned money. These weren’t loaner units and this wasn’t a sponsored review and you can draw your own conclusions."
"The AHB2 might look small and lightweight, but thanks to its clever engineering and power supply implementation, this little fellow could still deliver 190 Watts in 4 Ohms and 100 Watts in 8 Ohms, while maintaining an undetectable noise floor and distortion."
"For the craziest folks out there, you can even bridge two pieces together for ~580 Watts in 4 Ohms and 380W in 8 ohms."
- Sandu Vitalie, SoundNews.net
Excerpts from Printed Review
"Benchmark Media doesn’t need an introduction whatsoever, as their name implies - they’re committed to excellence. Besides bestowing world-class specifications, everything they make is backed-up by measurements produced by the world’s best audio analyzers."
"Luckily, Benchmark’s crew isn’t formed only by nerdy engineers, as you’ll find musicians, audiophiles and audio professionals throughout their ranks that don’t care only for the numbers (measurements), but for the end result as well."
The HPA4 Headphone/Line Amplifier
"I was given the privilege of reviewing the world-class Benchmark HPA4 preamp and headphone amp some time ago, that in time became my daily driver work horse. You can see it everywhere around here, it was put in at least ~40 reviews as all my headphones, DACs and power amp reviews were made with its help."
"It was both technical & linear sounding…and between you and me, this is exactly what I’m searching with all amplifiers that are passing though my hands: a metal box that will preserve the soul of the music, without adding or subtracting anything from there."
The AHB2 Power Amplifier
"The AHB2 might look small and lightweight, but thanks to its clever engineering and power supply implementation, this little fellow could still deliver 190 Watts in 4 Ohms and 100 Watts in 8 Ohms, while maintaining an undetectable noise floor and distortion."
"For the craziest folks out there, you can even bridge two pieces together for ~580 Watts in 4 Ohms and 380W in 8 ohms."
Build Quality
"Thor almighty! This thing has some amazingly thick panels all around it, adding a level of confidence and refinement. It looks plain and industrial, but I really dig its minimalist body."
"Thanks to its massive heat-dissipation fins, AHB2 runs very cool when idle and it remains as cool under most load conditions. It can get a little warmer under harder loads, but it was never hot under any circumstances."
Controls & Connectivity
"Being a power amplifier only, you won’t find remotes and volume controls with this one, there’s only a single On/Off button and several LEDs will be showing if it reached an over temperature, over-current, or clipping status and everything else is located on its back. There you’ll find your left and right speaker terminals, an AC socket in the middle, a pair of balanced XLR inputs and three NL4 speaker outputs (also called as SpeakON terminals) - that are mostly used in the Pro Audio world."
"This is a balanced only amplifier, so you won’t find single ended RCA inputs. A switch lets you choose its sensitivity depending on how powerful is your source. You can select between 2, 4 or 9.8 V inputs and another switch lets you choose its stereo or mono (bridged) operation. For mono mode, you will need two AHB2 power amplifiers."
Protection Systems
"You know what I like the most about it? Its bullet-proof protection systems!"
"Its protection systems will monitor its output voltage, output current, output distortion, output device SOA (safe operating area), power supply current, power supply voltage, AC line voltage, case temperatures and power device temperatures. Fault conditions silently mute both output channels in order to protect the speakers and amplifier from any damage. A status display shows the exact cause of the fault and the issues can be remedied in no time."
"As you well know, I’m switching digital sources on a weekly basis ... some of them offer preamp functionalities, while others don’t. I’ve replaced the excellent Gold Note DS-10 Plus & PSU-10 Evo stack with the SDA-6 PRO and I somehow forgot that the later doesn’t have a volume control, blasting 380Watts of power into my KEF Reference 3 after pressing the play button."
"A microsecond didn’t pass and both AHB2 engaged their protection circuits and muted themselves without causing any harm to my loudspeakers. For almost a year now, AHB2 saved my speakers twice."
Performance
"Benchmark is describing it as the quietest and cleanest audio amplifier on the planet. Some very powerful words right there, but considering its measured performance, AHB2 is still unrivaled by any other power amp when it comes to THD, Noise and dynamic range. I mean just look at those numbers. Show me another power amplifier than can deliver a measured dynamic range of 132 dB in stereo mode and 135 dB in mono mode and a total harmonic distortion of 0.00013% at Full Power."
Replacing Energy Storage Capacitors with Active Regulation
"Most high-quality power amplifiers have linear power supplies, large toroidal transformers and large banks of energy-storage capacitors. These linear supplies are sometimes unregulated and the capacitors help to remove ripple produced by the AC line. In contrast, AHB2 uses a tightly regulated resonant switching mode power supply that includes a very fast control loop. This control loop responds to audio-frequency load changes and keeps the supply voltage constant without the use of a large bank of capacitors. This active regulation is considerably more effective than capacitive energy-storage."
Test System Configuration
"AHB2 was used in a stereo setup and also in a headphone-based setup and yes, you’ve read that right!"
"I wanted to squeeze the last drop of performance out of it and that’s why I’ve used three different loudspeakers ..."
"AHB2 were also used in a headphone setup, directly driving a pair of Hifiman Susvara, which I already discussed in detail in my Hifiman Susvara review."
Driving KEF Reference 3 Loudspeakers
"Reference 3 are by far, the pickiest loudspeakers I’ve had in a very long time."
"When AHB2 replaced the S300, there were several immediate changes that jumped at me and those were absurd amounts of details coming forward that I didn’t encounter before, the speed and subsequently the impact of the sound drastically improved as well. The whole transient response jumped to a higher level altogether. Reference 3’s piston firing aluminum drivers are already known to be extremely fast and revealing sounding, but AHB2 added an iron grip, better controlling their attack and decay."
My Conclusion
"The key words with AHB2 are: world-class detail retrieval, absolute transparency, lightning-fast transient response, an open wide soundstage with a very precise layering and positioning of the notes around the listener, all tightly controlled with an iron grip, never sounding too mellow, sluggish or all over the place."
"The highest compliment I can give to AHB2 is that I purchased not one, but two units with my hard-earned money. These weren’t loaner units and this wasn’t a sponsored review and you can draw your own conclusions."
"If you’re searching for an honest, ultra-revealing, noiseless, transparent, lightning-fast and hard punching amplifier that wouldn’t limit the air travel, while providing an excellent imaging and depth, then AHB2 is one of the most impressive amps that passed through our HQ."
- Sandu Vitalie, SoundNews.net
Also in Reviews
AHB2 Review - Constantine Soo, Dagogo
"The AHB2 bridgeable stereo amplifier ... was the topic of a recent discussion between American electrostatic panel speaker manufacturer Sound Lab’s president, Dr. Roger West, and me."
"In our discussion, he related his highly positive experience in driving even his largest, $55k Majestic 945 panels with the $7,000 pair of Benchmark Media AHB2 monoblocks, along with the $3,050 LA4 Preamplifier and factory XLR cables."
"Dr. West described the AHB2 as a class AB design using “feed-forward distortion reduction [thus removing] any possibility of pushing the margin of safety of a standard feedback loop, used in most amplifiers, into an unstable oscillatory mode.”"
"He further shared with me that “this is of most concern on powerful musical transients. The distortion of the amplifier in the balanced mode is astonishingly low even at just below the clipping level of 380 watts.”"
"The prospect of the AHB2’s specified distortion level of 0.00015% or lower when at full volume is comical at first glance, but upon actual audition the impact of the achievement is very audible from medium-high listening levels and upward."
"It was unlike any other sub-$20,000 amplifier I have auditioned."
"My audition of the Benchmark Media AHB2 amplifiers underscores the reason Dr. West is so taken by it, and confirms the design is best described as a watershed moment in the high-end audio industry."
- Constantine Soo, Dagogo
DAC3 Review - Jerry Del Colliano
"Benchmark is a stalwart brand in pro audio, but has carved out a very respectable niche in the audiophile world with their diminutive but powerful components."
"The audiophile world sometimes looks to the professional audio world for enlightenment, especially on the digital side of things, and Benchmark Media is one of the companies that we put high on a pedestal."
"They are hardcore digital engineers freezing their asses off in upstate New York as they come up with some pretty innovative ways to get your varied digital sources sounding as much like the master tape as possible. Thank you for your service, gentlemen."
"If you really want to hear what your music sounds like in today’s streaming-driven world, this might just be the DAC that you need to test out."
- Jerry Del Colliano, Future Audiophile
DAC3 & AHB2 - System Review, Trevor Butler, The-Ear.net
"I began with the DAC3 HGC and AHB2 powering the glorious Morel Avyra 633 three-way floorstanders."
"This pairing created a full-bodied sound which brought the recording to life."
"Notable from the off was the bass from the DAC3 HGC and AHB2."
"Wow! It was deep, tight and conveyed a real feeling that the electronics were in charge of the transducers."
"Involuntary foot-tapping confirmed the timing ability and the overall presentation was spot-on, the Benchmark electronics created a fluent sound across a vivid soundstage; performers evident both tonally and spatially in an easy-to-believe presentation that brought the performance close."
"The Benchmark’s ability to retrieve deep-down detail and display it so well across the soundstage, with accurate positioning and convincing layering, made for a glorious re-creation of the recordings."
"To my mind the AHB2 is an amplifier with no obvious characteristics of its own: the level of transparency is sublime."
"Above all, the improved transient response performance stood out in a presentation that was not only lively but incredibly fast and revealing. The attack and decay displayed was awesome and not something I expect at this price point."
"The Benchmark DAC3 HGC and AHB2 are cracking products, sonically superior to a lot that’s available and well priced."
"They are superbly designed and built to an extremely high standard."
- Trevor Butler, the-ear.net