"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
"This little unit will change the way you look and listen to amplifiers."
"My first taste of this remarkable new amplifier came earlier this year in April at Chicago's AXPONA where I discovered it driving a newly redesigned Studio Electric Pasadena loudspeaker, also bearing the Benchmark trademark. Now called the SMS1, the Pasadena's crossover had been reworked by Benchmark, upgraded with very low tolerance components, and the new look, more in line with the look of the rest of the Benchmark product line up, had been adopted."
"The subsequent sound in this room was one of the most musically engaging I encountered at this year's event, a remarkable result considering its modest overall system price of just over $7000, sans source."
- Greg Weaver, EnjoythMusic.com
Jim Austin wrote, "The DAC3 was all about depths, in several respects . . . I heard deeper into the music."
The concise conclusion to John Atkinson's Measurements sidebar: "All I can say is 'Wow!'"
In a Follow-Up, Jim Austin 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.
- Stereophile Magazine
"Class A+" is Stereophile's highest award for Digital Processors
"Benchmark's LA4 is the widest-bandwidth, widest-dynamic-range, lowest-noise, lowest-distortion preamplifier I have encountered."
- John Atkinson, Stereophile
"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."
- Kalman Rubinson, Stereophile
"Class A" is Stereophile's highest award for preamplifiers.