"This THX-888 amplifier is driven by a Benchmark line amplifier that features relay gain control, relay input selection and relay muting. The gain control has a whopping 256 steps in impressive 0.5 dB increments so that you can get exactly the volume that you want to hear!"
"You get a brilliant Touch Screen that in the end provides easy access to the plethora of features and settings on the amplifier. Everything from balance control, input level offset selection, personalized input names, screen dimming, remote control and function-locking are only a touch or two away with the intuitive user interface. Throw in an optional remote control, and you really get everything you’d ever need with a dedicated headphone amplifier."
"The HPA4 is 100% analog and is driven by an upstream D/A converter (DAC). The THX-888 can easily deliver high voltage into low-sensitivity high impedance headphones and it can conversely deliver high current into low impedance headphones. It easily drove all of the headphones I had on hand from my 300 ohm Sennheiser HD800S, to my 32 ohm Grado PS2000e and power hungry Abyss AB-1266 Phi TC orthomagnetic headphones. Heck, it was also dead silent on lower gain with all of my in-ear monitors too like the Grade GR10e IEMs. It literally is both a jack of all trades and master of all!"
"I plugged in the HD800S headphones and quickly selected Holly Cole’s “Collection Vol. 1”. This collection of classic Holly Cole songs is one of my favorite “go to” albums."
"The tonality of the piano in “Trust in Me” was simply “life-like”. The tonality and detail of Holly’s piano playing was as if I was transported to a jazz club with Holly paying in front of me. Her vocals were seductive, transparent and perfectly portrayed. The HPA4 amplifier offered an incredibly close look into this recording with the ability to mine out the smallest details that other amplifiers would seem to gloss over."
"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
November 6, 2019
"The benchmark combination offers a full range of equipment that can hardly be topped, leaves nothing to be desired in terms of sound, and meets professional requirements without any ifs or buts."
"The HPA4 has the HIFIMan one hundred percent under control, eliciting neutral timbres, tons of spatial information and crisp dynamics."
"I connected everything the household had to offer in terms of speakers - Spendor S3 / 5, Ayon Seagull / c, Quad ESL57. It goes without saying that the American coped with the dynamic boxes with ease. But even the quads, which have some meanness on the part of their impedance, did not pose a challenge for the amp."
"There are many things that come into play when putting together a hi-fi system, one of which is synergy."
"After the arrival of the Benchmark Media Systems AHB2, I immediately thought of the matching HPA4 that colleagues Jaap and Yung were very pleased with."
"The key question, of course, was whether the HPA4 would really provide an audible improvement."
"Well you bet! The synergy between preamp and power amplifier is nothing short of magical, not to mention the DAC3 B that I got from importer Helios for the occasion."
"Not only a few curtains disappear, the whole window is gone."
- Geoffrey Vanhouwaert, Alpha-Audio
"The Benchmark AHB2 is a very fine sounding, easy to live with, zero-maintenance power amplifier that has enough power for most systems. If more power is needed, two amplifiers configured for mono can provide it. The decision to purchase the review sample and make the Benchmark AHB2 a new, long term reference took over a month of listening and comparisons."
"The outstanding musicality of the Benchmark AHB2 takes some time to convince the listener of its wholly musical presentation. This subtle excellence assures long term satisfaction."
-10 Audio, Perfect 10 Award