Holoaudio Bliss Level 1 headphone amp/preamp
With the Holoaudio Bliss Jeff Zhu’s approach to design is narrowing what once appeared to be an unbridgeable chasm between objectivists and subjectivists in the audio world. The brain behind Holoaudio is demonstrating that traditional, fully-discrete topologies not only have a place in subjectivists’ high-end systems but that they can compete with – and even exceed – the levels of technical performance offered by state-of-the-art integrated circuits if the implementation is up to snuff.
It’s no coincidence that the two best-measuring R2R ladder DACs currently in production both have Holo badges on them, Jason Kennedy reviewed the more affordable Spring 3 in 2021 and was seriously impressed by the musicality and resolution on offer for the money. Speaking of which, Holo products have earned a reputation for a quality of build and performance that punches well above their price points. Shortcutting the sales model by selling to customers through its two main distributors, Magna HiFi in Europe and Kitsune HiFi in the US, is no doubt why this company is able to be so competitive on pricing.
Holo’s latest product, Bliss, is a flagship headphone amplifier that promises to drive any earspeaker with ease. Zhu apparently used HiFiMan’s flagship Susvara as a reference during its development, this is a fiendishly current-hungry, planar-magnetic that has many owners reaching in despair for Benchmark’s AHB2 power amp. Bliss also functions as a preamplifier and, while it isn’t as generous as a full preamplifier in its provision of inputs and outputs, its sonic delivery is rumoured to snap dangerously close at the heels of HOlo’s flagship Serene preamp.
Holoaudio Bliss is fully-discrete and balanced from end-to-end with four sets of channels, each equipped with separate modules for buffering and amplification/attenuation functions. A total of eight of these are used to provide enough paired transistors to deliver the required power with linearity. Bliss’ dual-mono design provides 120dB channel separation and into a 32Ω load it outputs a maximum 12 Watts rms balanced and 3 Watts rms single-ended (the preamplifier circuits push up to 20 Volts rms and 10 Volts rms into balanced and single-ended power amps, respectively).
The stepped volume control uses precision relays to provide 86dB of adjustment (-72dB through +12dB) in 1dB increments with channel matching that’s better than +/- 0.1dB at all volume settings. The prominent, latch-like clicks heard inside the unit as the volume is adjusted soon become a reassuring part of the operating experience. There is no user-adjustable gain, this is cleverly taken care of by the relays that optimise the gain automatically according to the level the volume control is set to. This seamless behind-the-scenes gain management ensures the amp maximises its signal-to-noise ratio at all volume settings, meaning in-ear monitor enthusiasts needn’t worry about the potentially distracting noise floor they’d normally experience when plugging into an amp with high gain. Headphone amps with manually-adjustable gains often reproduce micro- and macro-dynamics differently depending on the setting; in my experience higher gain can trade composure and control for vividness and immersion. There is no such trade-off with Bliss, its auto-adjusting gain-staging delivers the same multifaceted listening experience irrespective of how much attenuation is dialled in.
Equal satisfaction
Build quality in the Holoaudio Bliss is as good as anything I’ve reviewed at this price and combines tank-like solidity with a premium finish. Most Holo products share the same black and copper-accented, slab-like, full-width chassis, this not only reduces manufacturing costs but also presents a streamlined look when stacked together. The layout of Bliss’s front panel includes a central LED display, copper push buttons for power, menu and mute and a large dial that controls volume and menu functions including input and output selection and display on/off. Even the optional remote control, which is all-too-often an afterthought, reassures with its weightiness. CNC’d from a solid block of aluminium and populated with more of the copper discs that decorate Bliss’s fascia, the RMT-2 is equally satisfying to use to control the amp. My only criticism is the omission of a power button, it would have been convenient to switch Bliss on and off without leaving the comfort of my listening chair.
The Holoaudio Bliss’ muting implementation differs from the norm in that once engaged the amp is effectively locked in a silent state that’s unresponsive to further instruction until the mute button is pressed again, this prevents the outputs from being re-engaged accidentally. Manual muting aside, when either the headphone or preamp output is selected the other output is muted automatically, this is handy for users like myself who are inconvenienced by unplugging headphones and switching off power amps.
There are total of three headphone outputs: two balanced (4XLR and 4.4mm Pentaconn) and one single-ended (6.3mm), and all three are active whenever the headphone output is selected. The rear of the unit offers three sets of line inputs (two balanced XLR and one single-ended RCA) and two pairs of pre-outputs (balanced XLR and single-ended RCA).
While tone, balance and crossfeed controls don’t yet have a place in Zhu’s purist approach, cycling Bliss’s outputs reveals two headphone settings, ‘Lo-Z’ and ‘Hi-Z’. On Lo-Z the 4XLR, 4.4mm Pentaconn and 6.3mm TRS connections have low output impedances of 0Ω, 2Ω and 1Ω, ensuring linear power transfer into the vast majority of loads*. On Hi-Z these increase to 15Ω, 17Ω and 8.5Ω, which reduces driver damping and induces tonal variations in low- and medium-impedance headphones whenever their impedance varies with frequency. In open-back, dynamic driver headphones this typically causes an increase in output around the transducer’s resonant frequency, which can be desirable when a warmer and more bass-focused presentation is preferred.
In keeping with many Holoaudio offerings, at the time of writing there are two versions of Holoaudio Bliss available; the Level 1 (base) model and the KTE (Kitsune) edition. The latter has been modded by Holo’s US distributor and sports several upgrades including a hand-wound O-type flat-wire transformer made from 6N copper, 1.5mm pure OCC silver wire linkages, rhodium-plated faston connectors, Red Nano fuse and Audio Note Kaisei capacitors. My impressions were formed with the Level 1, I did not audition the KTE.
*It’s likely the two jack outputs have been specified with a small amount of impedance on Lo-Z to protect the amp’s output stages from being shorted when plugging/unplugging (the 4XLR connector by design does not pose such a risk). The tonal variations induced by 1Ω and 2Ω output impedances usually become insignificant on headphones with nominal impedances greater than 8Ω and 16Ω, respectively.
Holoaudio Bliss sound quality
I spent most of my time listening to Bliss fed from the balanced XLR outputs of my reference Schiit Yggdrasil OG multibit DAC. I did, however, briefly swap in the newer Lim version of this DAC as well as Chord’s Hugo 2. The Holoaudio Bliss was very honest in contrasting the tonal and spatial characteristics of all three converters. There was no mistaking the Lim’s richer and more intimate presentation for Hugo 2’s paler and more ethereal delivery, but all three DACs had wonderful synergy with the Holo; it showcased what impressive performers they are at their respective price points without fear or favour.
Irresistible ear candy
Chris Isaak’s Wicked Game has the ability to flatter even the humblest of systems with its sparse yet sumptuous production. Something magical happens, however, when you play this track through gear that has a natural ability to reproduce the space around instruments as captured in the recording; it reveals there’s so much more going on than you think and the soundstage that’s reconstructed is so tangible it feels possible to walk through it. Isaak’s smooth and seductive vocal and James Calvin Wilsey’s tasty lead guitar licks are, of course, the star attractions and Bliss resolves their rich timbres, harmonic complexities and reverb structures with goosebump-inducing realism. The accompanying musicians are, however, just as integral to the track’s brooding mood and the Holoaudio Bliss brings them into clearer focus by providing a better vantage point from which to appreciate the performance as a whole. The bass guitar has a weighty thump but isn’t bloated or ponderous, it sits perfectly in the mix and has a firm but rounded texture with well-defined overtones. The kick drum that reinforces the bass line is clearly resolved as a separate instrument. The delicate strumming patterns of the acoustic guitars are beautifully articulated, as is their wide and deep placement in the soundstage, and the way the strings shimmer in space before decaying puts the glaze on what is utterly irresistible ear candy. I’d never grow tired of hearing this song – and countless others for that matter – on this amp.
Holoaudio Bliss’ imaging is uncannily tube-like in its holographic shaping of sounds. I’d actually swear I were listening to a valve amp if it weren’t for the fact that timbral neutrality, control, grip, speed and dynamics haven’t been unduly sacrificed to achieve such life-like dimensionality. The funky groove in Richard Page’s Shelter Me doesn’t translate as well on tubes as it does on transistors, it needs an amplifier with a strong hold to do justice to the snap of the percussion and timing of the bass. Bliss punches out this track’s rhythmic drive with unfaltering conviction without ever forcing it and – when partnered with a source and headphone that’s also up to the task – never leaves you wanting more.
Even if it did, I’d forgive it for the way it fleshes out instrument textures from the deepest fundamentals to the highest harmonics and treats the attack, sustain and decay elements of every note it plays with the same level of care. Not only that but the ease with which it aerates even the most densely layered soundscapes is quite remarkable. The background “whoas” in Toto’s I Will Remember can often be obscured by Simon Phillips thunderous drum kit on lesser amplifiers but Bliss is somehow able to separate them to the extent that you can identify the individual voices in the choir without losing any of the deep, visceral impact from the percussion or undermining the cohesiveness of the track as a whole.
Body and bloom
The Hi-Z setting injects a touch more low-end body and bloom into Focal’s flagship 80Ω Utopia and encourages a more forgiving and laid-back delivery from this usually unapologetically forward open-back headphone without sacrificing resolution. The slightly blunted transient attack suits some genres more than others but is undoubtedly conducive to longer listening sessions, especially when there are carbuncled productions on the playlist. The tonalities of high-impedance loads are less impacted by Hi-Z but the effects of the reduced damping are still noticeable on the 300Ω Sennheiser HD600, HD660S2 and HD800S with all three ‘phones becoming a touch more fluid and spacious. Neither an 8.5Ω nor 15Ω output impedance is enough to mellow the uncompromising speed and incision of the Beyerdynamic 600Ω DT880 or Audio-Technica 420Ω ATH-ADX5000 but I must say that, even on Low-Z, Holoaudio Bliss’ synergy with both of these headphones is almost certainly the most enjoyable and immersive I’ve experienced without there being tubes in the chain. When I play something like Chasing The Dragon’s fabulous binaural recording of Chabrier’s España, it doesn’t matter if I’m wearing Audio-Technicas, Focals or Sennheisers flagship open-back, they become my own, private, grand concert hall and I forget there are transducers strapped just centimetres from my ear drums. The out-of-head listening experience this Holo provides is addictive.
Pitting Bliss against the similarly-priced Sparkos Labs Aries was very informative. The Sparkos has been my reference solid-state headphone amp for almost two years and has engaged me more than any other transistor-based design I’ve heard up to its price as it injects just enough verve into its otherwise commendably neutral and transparent presentation to steer clear of sterility. The two amps are more similar than they are different but, in a direct comparison, Aries reveals a tendency to bring background information to the fore and accentuate leading edges. It is, as a result, slightly brighter and less forgiving than the Bliss without necessarily being more resolving. System synergy is, of course, key and there are instances where I’d favour the Sparkos over the Holo. When the partnering source and/or headphone lacks bite or is unable to resolve that last percentage point of detail, Aries’ touch of extra vibrancy is very effective at compensating for this. When the upstream gear and transducers are uber-revealing, however, Bliss would be my preference for its deeper soundstage and more effortless delivery.
Holoaudio Bliss preamp performance
Discovering Bliss’s preamplifier is every bit as good as its headphone amp is an unexpected bonus. When I partnered it with the Genelec 8030Cs in my nearfield office system I couldn’t quite believe what I was hearing so I promptly transported these modest, active desktop speakers into my main listening room for a proper evaluation. Even without the two BK XXLS400 subwoofers I later added to stretch the low end down to 17Hz, I was taken aback by the room-filling scale and unbridled dynamics I experienced from these diminutive nearfield monitors. The Holoaudio Bliss frees the music from the 8030’s enclosures better than any other preamp I’ve driven them with and offers up timing precision and transient attack that reminds me very much of the PMC Twenty5.24i I reviewed last year.
Despite hearing it dozens of times before, Bliss delivers the tom slams and kick drum during the intro to Richard Marx’s Take This Heart with such venom I actually flinched in my chair as they struck. Together with the much-improved clarity and instrument separation it feels like I’m listening to an audiophile remix of this ‘90s pop-rock gem, the increase in soundstage depth and height is quite remarkable. Robbie Robertson’s Somewhere Down The Crazy River shows the Holo’s soundstage width to be equally as expansive, it places one of the guitar licks so far beyond the right speaker that an unsighted guest would swear my room is several feet wider than it measures. I’m very much an eyes-closed listener but I found myself lifting an eyelid repeatedly during my month-long audition to check if the walls had moved.
Holoaudio Bliss verdict
Holoaudio’s long-anticipated flagship, balanced Class-A headphone amplifier proves it’s possible to get state-of-the-art technical performance from a fully-discrete design and make a product that’s both exceptionally transparent and sublimely spacious and natural-sounding. The fact that it’s also equipped with a preamp that performs at the same level makes Bliss an irresistible package, so irresistible that I’ve ordered one for myself; it would be foolish not to at this price.