"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
"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
The competition in the amplification category was very tight. There was a two-way tie for first place between two amplifiers that cost $30,000 a pair and $13,500 a pair.
The Benchmark AHB2 was just two points behind the leaders when the Stereophile reviewers cast their final votes. In all, there were 13 amplifiers that made Stereophile's select list of finalists. The Benchmark AHB2 was the least expensive amplifier on the list, yet it received top scores from the reviewers. The list included amplifiers with stratospheric prices. Six amplifiers were priced between $25,000 and $118,000 a pair!
At Benchmark we believe that a great audio system shouldn't set you back by the cost of a sports car.