"The HPA4 is Benchmark’s latest headphone amplifier. This amp is unusual in that it features a THX-888 Achromatic audio amplifier, which is claimed to reduce distortion by 20–40 dB through a patented feed-forward design, resulting in the world’s most linear amplifier. In addition to the THX amp circuitry, Benchmark has gone slightly nuts (in a good way) with the volume control, offering 256 levels in 0.5 dB steps via an array of relays. The idea is to limit noise and allow the user to dial-in volume precisely."
"The HPA4 is a high-voltage, high-current design to allow low-sensitivity headphones to work well. In addition, the damping factor is high (near zero ohms output impedance), with the aim of sounding the same with low-, medium-, and high-impedance headphones."
"I thought the HPA4 sounded as good as any headphone amp I’ve heard for dynamic headphones, and it might be the best of the lot depending on your circumstances."
"The HPA4 is exceptionally good at presenting a layered, dynamic, yet relaxed sound. You can hear these rich results on, for example, Eliza Gilkyson’s Hard Times in Babylon (Red House), where the instruments not only are clearly differentiated but also sound fully rendered, as live instruments do. You also can hear the overtones of each instrument as they decay, which makes them sound more real."
"... wish the review sample didn’t have to go back."
- Tom Martin, The Absolute Sound
"The afternoon before the start of the show I ran into John Siau of Benchmark Media Systems. He says to me quietly, “make sure you stop in our room, we have a surprise!” With curiosity suitably piqued, Co-Editor Jim Clements and I paid a visit ..."
"The results were pretty astonishing. A stable, enveloping stereo image that was devoid of any distortion whatsoever."
- Carlo Lo Raso, Secrets of Home Theater and High Fidelity
"Sound was extremely well-integrated and controlled, and the bass memorable."
"The Note received signal through the introductory version of the company's Liquid Cables. Each cable contains 27,000 wires. The company's introductory Elephant memory player joined Benchmark Media's AHB2 power amps, DAC3 B D/A processor, and interconnects."
"With the aid of a forthcoming DEQX HDP4 processor that's due in the fall, the system sounded super on a 16/44.1 file of the famed rendition of Copland's Fanfare for the Common Man, recorded by Eiji Oue and the Minnesota Orchestra for Reference Recordings."
- Jason Victor Serinus, Stereophile Magazine
"Laufer Teknik - The Note line array - The most immersive listening experience I had the entire show."
"There is no sweet spot because everywhere is the sweet spot. Even behind the speakers sounded incredible!"
"SVS Subs doing the low end work and Benchmark 380 watt class H monoblocked amps driving the arrays."
"I spent an extended amount of time in this room."
