HPA4 Review - Tom's Corner, What's Best Forum
HPA4 - "The Best Sounding Headphone Amp I've Heard"
"While you may think that any amp whose quiescent residual noise you cannot hear from your usual listening position is quiet enough, that has not been my subjective experience. This is one reason I'm now a big fan of the Benchmark equipment, including the AHB2 amp. I've been using a pair of them in bridged mono, as well as the Benchmark DAC3 HGC to drive my Harbeth M40.2s for awhile now."
"With this combination of electronics, for the first time in my audio life I can pin my ear to each speaker driver and hear absolutely no sound coming from the speakers in a quiet room with the system volume control at any position from minimum to maximum with no source material playing. Most amps produce quiescent noise under such conditions loud enough to be clearly heard at least a foot from a speaker driver, often more like several feet."
"I find that lowering the background noise paints the music on as black a canvas as possible and thus seems to bring out realistic low-level detail in recordings. While I may not actually hear residual amp noise as hiss/hum/rumble/roar, I more clearly hear the environmental ambient noise captured on the recording if the amp noise is lowered and this increases my perception of hearing the music in its recording venue, as well as my perception that the music is being made by real humans producing little noises like forceful breathing in rhythm, sub-vocalizations, lips parting, risers and chairs creaking, etc."
"For best headphone sound, use the four-pin XLR connector on the front panel of the HPA4, rather than the 1/4" TRS jack on the HPA4 ... the four-pin XLR connector has no chance of producing measurable distortion."
"Expect to hear quite-audible-from-the-listening-seat rapid clicking/chattering when adjusting the volume up or down with either the remote or front-panel volume controls. That's the sound of the HPA4 relays. If your SPL is already moderate or higher, the sound of the music may well cover up the sound of the relays. Just to be clear, this noise is purely mechanical and comes from the HPA4 chassis. There is no electronic clicking noise audible at all through speakers or headphones when the volume is adjusted."
"My reference headphones are the Audeze LCD-4 fitted with an aftermarket "balanced" Moon Audio Silver Dragon cable with a 4-pin XLR connector at the amp end."
"The whole presentation sounds more "solid" with the HPA4 than it did with the 430HA, giving the impression that the amp has a more solid grip on the drivers. The presentation gains a more "out front" aspect, with the presentation seeming significantly more in front of my head than it was before, while having equally wide spread. This is especially true of the NAD Viso HP50 headphones, probably because the subjective frequency response of those phones lacks any depression of the presence range and lower highs whatsoever and especially because of the "RoomFeel" response technology built into those phones."
HPA4 - "The Best Sounding Line Amp I've Yet Heard"
"The Benchmark HPA4 is the best sounding line amplifier I've yet heard. It's innovative approach to controlling system volume/SPL results in what for me is a uniquely transparent-to-source experience. It is also the best sounding headphone amp I've heard, both for very-insensitive, hard-to-drive phones and those sensitive enough to easily be used directly from a smart phone. The HPA4 truly stands apart in terms of measured and subjectively low background noise and distortion when driving either loudspeakers or headphones."
- tmallin (Tom), Moderator of Tom's Corner, WhatsBestForum.com
Note: Above quotes are from a very lengthy and well-written review of the HPA4 by tmallin (Tom) at What's Best Forum. We recommend following the links below and reading Tom's complete review.
Also in Reviews
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
DAC3 & AHB2 - System Review, Trevor Butler, The-Ear.net
"I began with the DAC3 HGC and AHB2 powering the glorious Morel Avyra 633 three-way floorstanders."
"This pairing created a full-bodied sound which brought the recording to life."
"Notable from the off was the bass from the DAC3 HGC and AHB2."
"Wow! It was deep, tight and conveyed a real feeling that the electronics were in charge of the transducers."
"Involuntary foot-tapping confirmed the timing ability and the overall presentation was spot-on, the Benchmark electronics created a fluent sound across a vivid soundstage; performers evident both tonally and spatially in an easy-to-believe presentation that brought the performance close."
"The Benchmark’s ability to retrieve deep-down detail and display it so well across the soundstage, with accurate positioning and convincing layering, made for a glorious re-creation of the recordings."
"To my mind the AHB2 is an amplifier with no obvious characteristics of its own: the level of transparency is sublime."
"Above all, the improved transient response performance stood out in a presentation that was not only lively but incredibly fast and revealing. The attack and decay displayed was awesome and not something I expect at this price point."
"The Benchmark DAC3 HGC and AHB2 are cracking products, sonically superior to a lot that’s available and well priced."
"They are superbly designed and built to an extremely high standard."
- Trevor Butler, the-ear.net