"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
"My initial impression was simple: The LA4 preamp plays everything that is, and nothing that isn't...Neutrality in Audio... and that's really all this review needs to convey."
"The LA4 preamp may occupy neutral audio country, but it is a sweet piece of audio kit. I love its form-factor. I love its simple operation. And I love that it allows the sound of the signal to flow through to the downstream components."
"The LA4's specifications are unquestionably excellent. When using pro-level balanced interconnects, the LA4 manages a Signal to Noise Ratio (SNR) greater than 135 dB, and Total Harmonic Distortion (THD) of -125 dB."
"The LA4 has a noise floor that is not just low, it's bats-strain-to-hear-it low."
"The Benchmark LA4 is an excellent preamp, an operationally solid spec-monster that also happens to sound great."
- Gary L Beard, Positive Feedback
"The headphone section, with its choice of 6.35 mm stereo or four-pin balanced XLR connectors ... really impresses with a smooth signal delivery."
"While on the one hand it can rock out when it needs to – its prodigious output means it can give as much power as your headphones can take – its sheer impact, openness and vivacity is jaw-dropping."
"An immaculate all-analogue design, the aptly named Benchmark is both technically and sonically as good as it gets."
- AV Tech Media Awards 2018/2019
Stereophile's editors chose 10 products to receive their top award, the "2018 Product of the Year - Editor's Choice Award". Two Benchmark products made this exclusive list - the AHB2 power amplifier and the DAC3 HGC D/A converter.
"I was impressed by this revolutionary stereo amplifier but it became an obsession when I mated three as monoblocks to a trio of Benchmark's DAC3s."
"The AHB2 is deadly silent, musically revealing, surprisingly compact, and quite powerful."
- Kalman Rubinson
"Benchmark has created a long line of DACs (several of which I've purchased) that present recordings with as little embellishment as is possible at their price points. The latest incarnation, the DAC3, is no exception, and excels at presenting the unvarnished truth, as the artist intended."
- Jon Iverson