"Here's a brand that's aptly named - its products providing a 'benchmark' technical performance. The HPA4 is no exception with its relay-switched stepwise volume attenuator calibrated in 0.5 dB steps over a 'useable' 105 dB range."
"Distortion and noise are vanishingly low."
"The frequency response is ruler flat (+/- 0.01) dB from 1 Hz - 100 kHz."
"The[line output] source impedance is a sensible 30 Ohms and the maximum output a huge 22 V."
"Via the headphone amp, the maximum voltage is 11.2 V and ... the maximum power output is a substantial 4.4W/25ohm and 7.7W/8ohm."
"So, not only will the HPA4 drive the toughest headphone loads but its ... insignificant -102 dBV (8uV) residual noise also ensures exceptionally quiet backgrounds when listening with the most sensitive headphones/earbuds."
"Distortion is broadly unaffected by loading."
"The source impedance is a low <0.6 Ohms up to 10 kHz, increasing to 0.78 Ohms at 20 kHz."
- Paul Miller, Hi-Fi News
"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
