"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."
"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."
"The Benchmark HPA4 exhibits virtually no noise, whether employed as a stereo preamp or headphone amplifier, and his highly transparent, with no audible colorations."
"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. 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."
"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."
- Steven Stone, HomeTheaterReview.com
"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