"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."
"Thanks to the special, discrete analog circuit/relay attenuator, this may be the most transparent line-stage preamplifier in the audiophile world."
"If you got a great-sounding source, the LA4 presents the audio in its original state — with gain or attenuation to the amplifier. I have never heard such low-level detail from a pre."
"The better the DAC, the better you hear it through a quality amp and speakers. It is quiet as a top-notch DAC, with S/N exceeding -135 dB and, feature-wise, it comes with unbalanced/balanced I/O and a really slick user interface."
"I use the four-input LA4 for audiophile A/B testing of DACs, monitoring my Hi-Res home recording/editing/mastering projects, as well as just listening how good my vast collection of 24 bit and DSD music sounds through an accurate amp and speakers."
"A steal at $2,500!"
- John Gatski, Everything Audio Network
"Since the HPA4 arrived, I have rediscovered so many of my favorite works all over again with improved detail retrieval dynamics and transparency that it’s hard to pull myself away!"
"It drove my power hungry Abyss Phi TC headphones with complete authority, but it was still dead silent and nimble enough to amplify my easy to drive Focal Utopia headphones."
"Rarely have I come across such a wonderfully revealing amplifier that can drive many different types of headphones so darn well! The solid build construction and various controls make the $2,995 price tag seem a bit low based on the other headphone amplifiers in this market space."- Peter Pialis, Headphone.guru
"Benchmark Media Systems’ LA4 preamplifier presented an utterly realistic reproduction of what was contained on each recording I played through it -- and weak recordings stood out more than usual. The LA4’s clean, analytical abilities are unmatched by any similarly priced preamplifier I know of. The LA4’s touchscreen brings it up to date with current user interfaces, and permits functions, such as balance control and muting at the device."
"If you want a preamp that editorializes, look elsewhere."
"If, like me, you value a high-resolution, totally neutral musical performance, add a Benchmark LA4 to your system, particularly if you already own a Benchmark DAC."
- Erich Wetzel, SoundStage! Hi-Fi