AHB2 Lab Evaluation - AVMENTOR.net
AHB2 - "Stable and Load-Independent, Capable of Driving Difficult Loads"
"This stable and load-independent behavior of the output stage is something not often encountered and adds, of course, another positive point for the device."
"AHB2's output power, near its clipping limit, was measured at 108Wrms per channel into 8 Ohm loads and at 190Wrms per channel at 4 Ohm loads, easily confirming the specs given by the company itself."
"Based on this performance, the amplifier seems more than capable of driving difficult loads."
"Damping factor was estimated above 200, therefore, no system frequency response discrepancies, due to loudspeaker's impedance variability, should be expected."
"In distortion measurements, AHB2's behavior was impressive with a total harmonic distortion and noise (THD+N) figure at 0.0009% for 8 Ohm loads and 0.0012% for 4 Ohm loads (measured at 1/3 of its maximum power) and harmonic distortion at 0.0005% and 0.0009% for 8 and 4 Ohm loads respectively."
"Intermodulation distortion (SMPTE) was also low, at 0.0005% and 0.0007% (8/4 Ohm loads). This performance clearly shows that the Benchmark/THX design approach works in practice as intended (at least from the distortion point of view) and the result is a power stage with very low distortion, indeed."
"The frequency response of the amplifier (with an 8 Ohm load) was practically flat with a slight attenuation towards the high-frequency part of the spectrum which is very progressive and does not exceed 0.3dBr at 60kHz."
"The noise performance of the amplifier was, also, top-class. With a reference level corresponding to 1Wmrs/8 Ohm, the signal to noise ratio was measured at -109dBr (A) (with a 1kHz input signal) and the dynamic range at 129dB."
"In both spectrum graphs, there is an apparent absence of noise components from the power supply and their intermodulation products in the low-frequency range (the 50Hz component is hardly distinguishable), all of them being below -130dBr. This is a remarkable behavior, especially with the output stage under load conditions, which justifies the choice of a switch-mode power supply."
"Finally, the square wave response shows a very good transient behavior, without any particular problem. Slew rate was estimated at 16V/uS and rise time at 3.5mS, a value that corresponds to a conventionally calculated bandwidth of 100kHz."
- Dimitris Stamatakos, AVMENTOR.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