"Benchmark describes its product as a 'reference Stereo Headphone Amplifier and Reference Line Amplifier with Relay Gain and Input Control', which should give you some idea of what's going on here, but only hints at the fact that this is actually two completely separate products packed into one relatively compact unit."
"Unlike most headphone amps able to do double duty as a preamp, this one doesn't split its output ... but actually has discrete amplifier sections for the two functions."
"The headphone section is powered by a power amp from THX, employing the same AAA (Achromatic Audio Amplifier) technology first used by the company in its AHB2."
"Benchmark's line amplifier uses relays for input selection, gain control and muting while four independent 256-step attenuators ... feed the the headphone ... and preamp outputs."
"As PM notes in his Lab Report, this design gives the HPA4 not only outstanding performance, but also rather impressive - to say the least - signal delivery."
"All of a track or two should do the trick, as whether with revealing headphones ... or used as a preamp, the HPA4 simply drops jaws with the sheer impact, openness and vivacity of the way it plays music."
"I played a new Channel Classics recording, pianist Anna Fedorova's Four Fantasies [CCS 41318; DSD 256], and was instantly struck by the way it sprang to life, with every element of the playing, and the size of the Steinway in a credible concert-hall acoustic, readily on display."
"It was one of those real 'performer in the room' experiences and I was instantly transported back to the time I spent monitoring the recording as it was being made in the Eindhoven Muziekgebouw back in July."
"The HPA4 can certainly rock out, it prodigious capability when it comes to output levels meaning it can five as much as your phones can take."
"Its beauty is that it sets no limits on your system: any failings audible will need to be looked for elsewhere."
- Andrew Everard, Hi-Fi News
"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