HPA4 Review - Tom Fine, Tape Op
HPA4 - "Cleanest, Quietest, Most Neutral, Dynamic and Precise"
"Allow me to rave about the HPA4’s built-in headphone amp. Designed using similar technology as the AHB2 and licensed from THX (Benchmark calls it the THX-888 Amplifier), this is the cleanest, quietest, most neutral headphone amp I’ve ever heard."
"The HPA4 has no trouble playing music dynamically and precisely through any headphones I own."
"When the folks at Benchmark suggested a review of their HPA4 for Tape Op, my first reaction was, “Isn’t this aimed more at the audiophile market?” Benchmark’s Rory Rall replied that I should consider its use as a reference-grade monitor controller, with a world-class headphone amp built-in. He recommended I pair it with my Benchmark DAC3 B digital-analog converter and use it to drive my Benchmark AHB2 [Tape Op #111] power amp."
Four Years Experience with the AHB2
"When I previously reviewed the Benchmark AHB2, I described it as being as close to a straight wire with gain as I’ve ever heard – “a silent transmitter of musical energy.” I stand by that description after four years of living and listening to it."
"With the DAC3 B and HPA4 ahead of it, the whole signal chain runs silently and transparently."
The HPA4 Allows the DAC to Run Wide Open
"The HPA4 is built on the idea of avoiding any sort of bit-stripping volume control in the digital realm. So a full-output DAC sends it line-level audio."
"Inside the HPA4 is a precision relay-controlled analog attenuator, with exact channel-to-channel matching and a measurable/repeatable gain or attenuation (expressed in dB on the large color touch-screen front panel display). The volume knob is a 256-step precision encoder, driving relays that engage resistors, in 0.5 dB steps."
"You can memory-set a gain level for each input, so for instance, if you wanted to compare an analog source to a digital transfer, you can precisely level-match. Or (like I often do) measure an original LP release against a digital remaster. Or set your mixer’s output with what’s coming out of your digital rig. The possibilities are limited only by your line-level sources and the HPA4’s four inputs."
Headphone Amplifier
"Finally, in what may be a case of “burying the lede,” allow me to rave about the HPA4’s built-in headphone amp. Designed using similar technology as the AHB2 and licensed from THX (Benchmark calls it the THX-888 Amplifier), this is the cleanest, quietest, most neutral headphone amp I’ve ever heard."
Headphone Output Power
"The HPA4 has no trouble playing music dynamically and precisely through any headphones I own."
"I don’t turn the HPA4 any louder than -30 dB, and lower than that for rock music. Putting it in numbers, the THX-888 headphone amp is capable of peak-to-peak voltage swings of 25V and an output of 1.5 amps. It puts out 6 watts into 16 ohms! This should give you the idea that this thing will drive any low-efficiency cans you want to plug in."
The Price
"For all this silence and neutrality you have to pay a pretty penny, but is it worth it? As with all pieces of your system, it depends. For a precision monitoring setup for mastering, detailed mixing situations, or even a top-shelf listening system, you’ll have to look hard (and maybe spend more) to get this close to the fabled “straight wire with gain” sound."
Conclusion
"I can’t think of anything else that will get you closer to the sound coming out of your sources. Combined with Benchmark’s DAC and power amp with excellent speakers and headphones plugged in, this is quite the monitoring chain."
"When playing music you love, it will fire all the pleasure synapses."
- Tom Fine, Tape Op
Also in Reviews
AHB2 Review - Mike Prager, Future Audiophile
"For years, the audio world acknowledged one main contender (at least at sub-five-figure pricing) for the quietest, cleanest, most neutral power amplifier around. That was the Benchmark AHB2, whose specifications are still, for all practical purposes, unsurpassed, even by today’s excellent Class-D amps."
"10 years after its release, the Benchmark Media Systems AHB2 stereo power amp is still a standard-bearer in clean, neutral sound in the audiophile world."
"I greatly enjoyed having a pair of AHB2s in my system – their purity, neutrality, and seemingly unlimited power provided a clear window on the music and a lot of joy."
"I especially appreciated the AHB2’s smooth, well-integrated treble, free of splashiness or grain, and its natural reproduction of the human voice."
- Mike Prager, Future Audiophile
AHB2 Review - Constantine Soo, Dagogo
"The AHB2 bridgeable stereo amplifier ... was the topic of a recent discussion between American electrostatic panel speaker manufacturer Sound Lab’s president, Dr. Roger West, and me."
"In our discussion, he related his highly positive experience in driving even his largest, $55k Majestic 945 panels with the $7,000 pair of Benchmark Media AHB2 monoblocks, along with the $3,050 LA4 Preamplifier and factory XLR cables."
"Dr. West described the AHB2 as a class AB design using “feed-forward distortion reduction [thus removing] any possibility of pushing the margin of safety of a standard feedback loop, used in most amplifiers, into an unstable oscillatory mode.”"
"He further shared with me that “this is of most concern on powerful musical transients. The distortion of the amplifier in the balanced mode is astonishingly low even at just below the clipping level of 380 watts.”"
"The prospect of the AHB2’s specified distortion level of 0.00015% or lower when at full volume is comical at first glance, but upon actual audition the impact of the achievement is very audible from medium-high listening levels and upward."
"It was unlike any other sub-$20,000 amplifier I have auditioned."
"My audition of the Benchmark Media AHB2 amplifiers underscores the reason Dr. West is so taken by it, and confirms the design is best described as a watershed moment in the high-end audio industry."
- Constantine Soo, Dagogo
DAC3 Review - Jerry Del Colliano
"Benchmark is a stalwart brand in pro audio, but has carved out a very respectable niche in the audiophile world with their diminutive but powerful components."
"The audiophile world sometimes looks to the professional audio world for enlightenment, especially on the digital side of things, and Benchmark Media is one of the companies that we put high on a pedestal."
"They are hardcore digital engineers freezing their asses off in upstate New York as they come up with some pretty innovative ways to get your varied digital sources sounding as much like the master tape as possible. Thank you for your service, gentlemen."
"If you really want to hear what your music sounds like in today’s streaming-driven world, this might just be the DAC that you need to test out."
- Jerry Del Colliano, Future Audiophile