"THX has patented a novel amplifier design, THX AAA Technology(TM) and Benchmark Media Systems has turned it into a new power amplifier – AHB2. The design is called Achromatic Audio Amplifier. Achromatic may mean colorless or neutral or without modulation. The AHB2 is an attack on current amplifier design. It’s basically an AB amp with a class H power rail arrangement."
"A low power Class A correction amplifier ... runs in parallel with the regular AB amplifier ... and corrects ... non-linearity in the transition stage."
"The AHB2 is a class AB amp – but could easily be mistaken for a class D with its very compact dimensions. The small size is made possible by the compact switching power supply."
"The AHB2 has a resonant zero-voltage switching power supply. The switching is carried out at frequencies well above the audio band to reduce any audible artifacts from the power supply. Switching power supplies are much more efficient, and smaller, than linear transformer based supplies."
"The AHB2 power supply is regulated and very efficient in combination with the H Class rails. Benchmark claims that there is no sagging in internal voltage during high loads or when line voltage dips."
"The amplifier has a spectacular frequency response of 0.4 Hz to 200 kHz. This means that the AHB2 will amplify the high frequencies present on high res digital files."
"So is there a sound signature to the AHB2? Since THX calls it Achromatic we can assume that they were not aiming for a warm and sweet tubey sound – and this is not what it delivers. The sound is indeed neutral and exact without being sterile or clinical. Colorless? Not really. The amp will send through the sound palette of the source component and disc/file without stripping any color away."
"The Benchmark AHB2 is a solid foundation for an audio system. It is very quiet with extremely low distortion."
"The AHB2 is so good it will immediately expose weaknesses in your system. It requires a very good pre-amp ... which should output a balanced signal."
"Medals to everyone and a rebel princess to the AAA Technology inventor!"
- Toby Tingskog, dagogo.com
Benchmark's Rory Rall shows a storm trooper the AHB2 power amplifier at the NAMM 2016 Show, and explains the new THX AAA Technology. Rory waved his hand and was heard to say: "These are the amplifiers that you are looking for."
"Before I dig into the sound of the LA4 it is important to know that it employs a wide bandwidth design. The LA4’s bandwidth is specified at 0.2 Hz to 500 kHz."
"Most of the wide bandwidth designs I have heard exhibit ... a purity in tone with superb timing and speed ... the LA4 proved to be no exception."
"The Benchmark LA4 yielded a change that was quickly apparent in several areas. Notably were; bass, upper midrange, treble, low-level listening, and the ability to distinguish the colorations of other components that were contributing to my overall sound."
"Acoustic guitar, piano, and harmonica among many other instruments are presented with speed, clarity, and coherency that made them sound more “present” in the room and less like a recording."
"The Benchmark LA4 is simply the most transparent, least colored, and most revealing component I have had in my system to date. I look forward to it joining my stable of reference components."
- Ken Redmond, The Audio Beatnik
"This little unit will change the way you look and listen to amplifiers."
"My first taste of this remarkable new amplifier came earlier this year in April at Chicago's AXPONA where I discovered it driving a newly redesigned Studio Electric Pasadena loudspeaker, also bearing the Benchmark trademark. Now called the SMS1, the Pasadena's crossover had been reworked by Benchmark, upgraded with very low tolerance components, and the new look, more in line with the look of the rest of the Benchmark product line up, had been adopted."
"The subsequent sound in this room was one of the most musically engaging I encountered at this year's event, a remarkable result considering its modest overall system price of just over $7000, sans source."
- Greg Weaver, EnjoythMusic.com
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
"Class A+" is Stereophile's highest award for Digital Processors