HPA4 and AHB2 - "The Quietest Rig I've Heard (or Not Heard)"
"The HPA4 combined with the Benchmark AHB2 power amplifier ranks as the quietest rig I've heard (or not heard). Even with the gain up to full with no signal, there is no hiss, hum, or buzz, even when I placed my ears within a in inch of the drivers on 89 dB sensitive loudspeakers."
"The Benchmark HPA4 exhibits virtually no noise, whether employed as a stereo preamp or headphone amplifier, and his highly transparent, with no audible colorations."
"As a Headphone Amplifier, the HPA4 was First Rate"
"Whether it was my most power-hungry headphones, which currently are the new Abyss Diana Phi, or my most sensitive IERs, such as the Empire Ears Phantoms, there was no added noise or lack of adequate gain."
HPA4 - Front Panel
"The HPA4's front panel is a simple affair, with an on/off button on the extreme left side followed on the right by quarter-inch stereo and XLR balanced headphone connections and a large volume control that has four independent 256-step attenuators in half-decibel increments. This permits the volume level adjustments for the line level and headphone outputs to be completely independent from each other."
HPA4 - Touch Screen
"The HPA4 also has a full color touchscreen for setup and control."
"The front panel controls offer several welcome features, including the ability to control both the headphone and line level outputs separately or ganged together. Unlike many preamp/headphone amplifiers, which automatically mute the line level when a headphone is plugged in, the HPA4 gives users the option of using both at the same time."
HPA4 - Rear Panel
"In addition to its pair of stereo outputs, the HPA4 has one more output: a line-level summed mono, which could be useful in connecting a subwoofer if yours doesn't have stereo inputs."
"The HPA4 occupies a unique place, not only due to its features and performance, but also its price. Sure, there are plenty of decent line-level preamplifiers, DACs with built-in volume controls, and scads of headphone amps, but to get the same level of ergonomics and performance as the HPA4 for the same money from separate components could be a challenging proposition, depending on your needs."
"Benchmark calls the HPA4 a "Reference stereo headphone amplifier and reference line amplifier," and I found no reason to dispute this. It performed at reference level with whatever I threw at it. It is ergonomically elegant with a well-laid-out remote and front panel controls. Also, its headphone amplifier was able to support a wide variety of headphones and is the first component to utilize THX Achromatic Audio Amplifier (AAA) technology."
"If you are looking for a preamplifier/headphone amplifier that you can live with happily for a long time, you should consider the Benchmark HPA4 at the top of your must-audition list."
LA4 - Receives Stereophile's Highest "Class A" Rating for Preamplifiers
"Benchmark's usual approach to design is to out-spec the competition, and so it is here. Like other Benchmark equipment he has tested, the affordable LA4 challenged the resolution of John Atkinson's test instruments, with'superb'channel separation,'extremely low noise, and virtually no power-supply-related spuriae.'"
"Benchmark's LA4 is the widest-bandwidth, widest-dynamic-range, lowest-noise, lowest-distortion preamplifier I have encountered."- John Atkinson
"In his listening room, Kalman Rubinson compared the LA4 to a cable—and couldn't hear any difference. He concludes,'the LA4 is probably the most transparent and revealing audio component I've ever used. It does not seem to leave any fingerprints on the sound.'"
"The DAC3 B is a stripped- down, lower-priced version of the DAC3 HGC, which omits the headphone amplifier, balanced and unbalanced analog inputs, volume, mute, and polarity controls."- Stereophile
"The DAC3 was all about depths, in several respects...I heard deeper into the music."
"All I can say is Wow!"
- John Atkinson
"In a Follow-Up, JCA 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."