Norway’s Hegel Music Systems makes CD players, DACs, and amplifiers -- integrated, pre-, and power -- and since its founding has focused on solving the problems that plague contemporary amplifiers, such as harmonic distortion. In fact, harmonic distortion so intrigued founder Bent Holter that, in the late 1980s, he wrote his thesis on the subject. Among the technologies to come from this research has been Hegel’s patented SoundEngine circuitry -- now reincarnated as SoundEngine2 -- which seeks to retain the original detail and dynamic range of the signal with error-correction technology. The various stages of an amplifier -- input, gain, output -- are usually connected in series. The trouble with this is that any distortion produced in one of these stages is then sent on to the next stage to be amplified, along with the signal. At the end of this series, this cumulative distortion is then, hopefully, minimized by a global feedback loop.
Hegel’s approach is different. Rather than relying on a feedback loop, its SoundEngine feeds forward. Each block is checked for distortion; if any distortion is detected that reaches the specified threshold of audibility, the distortion signal is inverted, then added to that block’s output signal to cancel out the distortion. In a recent SoundStage! InSight video, Hegel’s Anders Ertzeid describes the Hegel sound as being about “dynamics and no pollution” by distortion-producing electronics. Hegel prefers to ensure its products’ longevity by implementing key features well rather than by checking every possible box, as some manufacturers do.
Hegel debuted the H90 DAC-integrated amplifier ($2000 USD), successor to the H80, in May 2017, at the High End show in Munich, Germany. It’s based on the framework of their well-received Röst integrated ($3000), now joined by the H190. Both the H90 and H190 include the SoundEngine2 circuitry, which makes possible wider dynamic range and a higher damping factor (see below), for better control of low frequencies. Both the H90 and H190 have built-in digital-to-analog converters and support Apple AirPlay and UPnP; the H190 adds IP control and Control4 for integration with home-automation systems; a forthcoming software upgrade for the H190 will support Spotify Connect.
The H90 is dense, measuring only 16.93”W x 3.15”H x 12.20”D but weighing 26.5 pounds. My review sample seemed impressively built; its steel case had superb fit and finish and was covered in a powder coat of black. Although a substantial toroidal transformer is visible through the top panel’s vents, the heat dissipation seems well designed -- the H90 never got too warm to the touch, even in long listening sessions. The aluminum front panel thickens toward the center, and has an understated elegance. On it are indexed knobs for source selection and volume, an OLED screen, and, at the far right, a 1/4” headphone jack; other than Hegel’s logo, that’s it.
The screen displays the source selected, the volume level, network connectivity, and the signal’s sample rate. I could easily read all of this from my listening chair: the source and volume appear in white in a large, bold, sans-serif font. The remote control switches the H90 from Standby to On, but at first I couldn’t find the main power switch. Turns out it’s on the bottom plate, just in front of one of the H90’s three beefy rubber feet. Should have checked the manual.
On the rear panel are two sets of analog inputs (RCA), one set of line-level outputs (RCA), two pairs of speaker binding posts, the inlet for the detachable IEC power cord, and the digital inputs: one coaxial, three optical, one USB Type-B, and one Ethernet -- no Wi-Fi. The H90’s home-theater mode can be set with its remote control. Each analog, optical, and coaxial input can be individually toggled from variable (default) to a high fixed level appropriate for an AVR or pre-pro preamplifier output, rather than to line-level output. The H90 remembers these settings even after being completely turned off.
The H90 is specified to put out 60Wpc into 8 ohms with less than 0.01% distortion. The signal/noise ratio is more than 100dB and the crosstalk less than -100dB, all to be expected in this product class. What’s astounding is the H90’s damping factor, or the ratio of the loudspeaker’s specified impedance to the impedance of the source: more than 2000. This likely indicates great control of the large woofers of full-range loudspeakers. The H90 drives headphones with a discrete amplifier -- a first for an entry-level Hegel amp.
While some makers of integrated amplifiers try to map the ever-changing landscape of network streaming protocols, Hegel has stuck with those that have demonstrated staying power: UPnP/DLNA and Apple AirPlay. The H90 presents itself as a DLNA digital media renderer -- that is, as a target to which to push audio files. This is my preferred approach for large media libraries, which I find easier to manage on a computer. When, in File Explorer on my PC running Windows 10 Professional v.1709, I select a supported music file -- WAV, AIFF, FLAC, Ogg, or MP3 -- the H90 appears as a network device and as a context menu choice for “Cast to Device.” A graphical interface for the Cast to Device server appears that looks like a miniature Windows Media Player, including transport control and playback queue. Additional files can be dragged and dropped to the queue -- though it was smart enough to prevent me from adding to the queue an unsupported DSD file. If the H90 is in standby, it will awake and switch to the network source when media are cast to it. Third-party applications such as JRiver Media Center and foobar2000 (the latter requires UPnP component plugin) can also be used to feed the H90 as a renderer. On the Mac, the Hegel makes use of the Bonjour service.
Apple AirPlay can be used from iTunes or a mobile device (natively and officially on iOS or via an app like doubleTwist on Android). iTunes can play with multiple AirPlay targets in whole-house audio systems, a capability included in iOS in 2017. Because the H90 lacks a Wi-Fi antenna, to play from a mobile device the amp must be connected to a network with a wireless access point. Once set up, the H90 appears in the software’s list of AirPlay speakers, and the app is given control over the transport and the Hegel’s volume. AirPlay is a convenient if less than ideal solution, as there’s some overhead from transcoding to Apple Lossless (ALAC, 44.1kHz). While AirPlay allows the screen of the iOS device to be turned off during playback, the device must remain on and connected to the network, which will drain its battery.
I began my listening session by playing CDs on my Music Hall MMF CD-25 CD player, plugged into the H90’s optical input. The Earth and Its Creatures, the first movement of Heitor Villa-Lobos’s Symphony No.10, “Amerindia,” with Gisèle Ben-Dor conducting the Santa Barbara Symphony Orchestra (CD, Koch International Classics 3-7488-2 HI), evokes nature with its multiple layers of fluttering birds in the flutes. The H90 kept this multiplicity of voices at once cohesive and distinct, each instrument occupying a specific position in space and reproduced at a unique dynamic level. Later movements of this work are scored for chorus (the Santa Barbara Choral Society and Donald Brinegar), and here the H90 maintained the energy of a rambunctious brass line that slipped smoothly into choral oohs and aahs. I’ve often thought of Villa-Lobos (1887-1959) as a man out of sequence -- the last of the nationalist composers whose zenith was the late 19th century, though he came to prominence between the world wars. Written for the 400th anniversary of São Paolo, his Symphony 10 tells, in oratorio style, a history of Brazil, the chorus singing in the languages of the native populations, the missionaries, and the European settlers: respectively, Tupi, Latin, and Portuguese. The words are sung to various motifs, to which are added the syncopated cross-rhythms of the descendants of African slaves. At times, the rest of the forces go silent to expose the voices of individual singers, much as in operatic recitative. Here, the musical magic could be easily destroyed were it not for the H90’s admirably low, if not inaudible, self-noise. Soon, full orchestra and chorus return in this workout of dynamic range. The sound was never congested, nor were voices or instruments lost in the mix. The ensemble was tightly woven, and wind bell tones were rounded and pronounced. Chimes and brass painted silvery textures, laid over the sweetly lyrical lines sung by the altos. Motifs were very much individual, alternating and competing, until all swelled in a concluding, unison “Alleluia!” with which the H90 filled my listening room.
Likewise, experimental rock of the 1970s took advantage of the H90’s impressive control and precision. The CD layer of Pink Floyd’s classic The Dark Side of the Moon (SACD/CD, Capitol CDP 5 82136 2) provided opportunities to explore expansiveness of dynamic range, soundstage size, and tonal nuance. Before the voices enter in “Time,” there is a gradual introduction consisting of a cacophony of clocks and chimes, a metronomic beat box, reverberant bass, keyboards, and drum touches spread over the soundstage quite unnaturally -- not as a live band would distribute themselves.
This hybrid disc also contains multichannel and two-channel DSD mixes of the album; I’m familiar with both, and am always curious to hear how much “multidimensionality” a two-channel integrated amp and two speakers can extract from the two-channel mix. In the case of the H90, quite a bit! The soundstage was wide and deep, and the sonic textures of the numerous sounds never got lost, but combined into something more than the sum of the parts. I appreciated the nuanced decays of guitar chords, and the H90’s responses to rapid changes in dynamics.
The Dark Side of the Moon also gave me a chance to assess the H90’s raw power. It was certainly more than I needed, and the music came into its own when given a bit more juice. The bass was well controlled -- lower-midrange notes were coaxed from my Sonus Faber Principia 3 monitors in a deliberate manner. The walking bass line in “Money” pulsated through the room as the sounds of coins flew between the speakers. Dick Parry’s saxophone sounded rawly emotional. The H90 got out of the way to present me with the music. Toward the end of “Money,” some phased responses are panned hard left and right, a detail I don’t recall having heard before. Similarly, the heartbeat that ends “Eclipse” was presented in solitary starkness.
In comparisons with my NAD C 356BEE integrated amplifier ($900) with classical music, the H90 generally opened up the sound to something more like the enveloping acoustic of a concert hall. The soundstage was given greater dimensionality. When I switched to the H90 from the NAD while listening to Mahler’s Symphony No.7, with Claudio Abbado conducting the Berlin Philharmonic (CD, Deutsche Grammophon 289 471 623-2), I felt as if my seat had been upgraded. The brasses packed more punch; the bass and low midrange exhibited greater dynamic control. Where the NAD provided more raw power, the Hegel did it with finesse, pushing forward details in the first movement’s march for full orchestra. At the same time, isolated mallet strokes on timpani and bells decayed naturally, and were imaged distinctly. The Hegel’s key advantages were in dynamics and details.
To get a sense of the H90’s support of codecs and containers, I tried different types of files stored on my PC’s music library. I was successfully able to play FLACs at the sampling rates of 44.1, 88.2, 96, 176.4, and 192kHz, as well as MP3s. As expected, protected AACs wouldn’t play, while unprotected ones did. DSD files (DFF) didn’t play, nor did 44.1 or 192kHz AIFF files.
“If I Were a Bell,” from Relaxin’ with the Miles Davis Quintet, exhibited Davis’s signature trumpet sound (24/96 FLAC, Prestige/HDtracks), lightly emphasizing pitches and displaying a tight handoff to John Coltrane on tenor sax. The H90 reproduced what detail and dynamic range this 1956 mono recording contains, particularly in Coltrane’s solo and when the bass and drums sit out, exposing the start of Red Garland’s piano solo. Instruments were well rendered at their natural sizes, and the sound of the upper range of the piano was delicate.
With a more modern recording -- Shostakovich’s Festive Overture, with Gustavo Dudamel conducting the Simón Bolívar Youth Orchestra of Venezuela (24/48, Deutsche Grammophon/HDtracks) -- the H90 offered exciting authority and energy as themes were traded off among various sections of the orchestra. This recording sounds a touch bright through some DACs; through the H90 it sounded more crisp than bright. By this time I’d come to expect expert handing of dynamics from the H90, and it didn’t disappoint. There was no congestion as the competing orchestral voices were imaged appropriately across a broad soundstage. The brasses’ attacks and rapid decays sounded natural. Toward the end of the work, themes played in unison, and motifs toward the end exhibited a tight ensemble.
Initiating AirPlay was simple. The H90 was selectable from the menu in iOS 10, in the app’s playback view. Keep in mind that the iOS device will then control the H90’s volume, beginning at whatever level is set on the mobile device -- and in my case, that was too high. In the contemplative title track of the Maria Schneider Orchestra’s Sky Blue (AAC, Artistshare), Steve Wilson’s sweet soprano sax easily filled the room at a bit higher on the dial -- “40” -- than CD sources did. This piece for big band begins with unison horn chords that, when the saxophone soloist supplies a melody at the front and center of the soundstage, remind me of a funereal motif by Ralph Vaughan Williams. The saxophone’s sound in this track can be a bit saccharine, but wasn’t overly so through the H90’s DAC. The instruments contesting for dominance at the midpoint of “Sky Blue” remained distinguishable, and, at the close, the H90’s dynamic range delivered varying levels of intensity as Wilson mimics birdsong.
In “Strasbourg/St. Denis,” from the Roy Hargrove Quintet’s Earfood (AAC, Universal 787733), each player is given a chance to shine. After bassist Danton Boller sets the groove, trumpeter Hargrove lays out the tune’s melodic contours. The music is equal parts post-bop jazz, groove, and funk, and the H90 maintained the energy as each player improvises with a happy, chatty staccato. Through all of my listening via AirPlay over my 802.11n network, the H90 never dropped a note.
The Hegel H90’s USB input supports 44.1, 48, and 96kHz sample rates but not DSD, or the less common 88.2, 176.4, and 192kHz rates. It is also class-compliant -- no specific driver needs to be installed for use with Windows. I found that not every USB cable would work; I had to try a few before Windows would recognize the device, but this didn’t require an “audiophile” USB cable. With the optional WASAPI component installed, foobar2000 sees the Tenor TE7022 USB receiver chip as an output option. When I set foobar2000 to use WASAPI in “push” mode, the H90 correctly displayed the sample rates of the various FLACs I sent it -- so long as they were 44.1, 48, or 96kHz. But when I sent it an 88.2kHz FLAC file, it displayed a blue screen and I had to reboot it. While I appreciate and understand the decision not to ship a driver and thus support a limited set of files, these should be listed in the owner’s manual. But within those constraints, and listening to Schumann’s Symphonic Etudes as performed by pianist Freddy Kempf (24/96 FLAC, BIS/eClassical), I was happy with the H90’s sound: lyrical, crisp, and detailed, with depths of dynamics and intensity.
The headphone outputs built into many integrated amplifiers are weak afterthoughts that necessitate the purchase of an outboard headphone amp. While the Hegel H90’s headphone amp is an integrated circuit, it’s implemented well and is backed by a good power supply. As usual, when a 1/4” headphone plug is inserted in the jack, the H90 automatically mutes the speaker terminals.
The H90 had no problem driving HiFiMan’s notoriously demanding HE-500 headphones ($599), delivering the rich, complex sound of the multiplicity of voices in Sibelius’s cantata Oma Maa, with Paavo Järvi leading the Ellernhein Girls’ Choir, the Estonian National Male Choir, and the Estonian National Symphony Orchestra (CD, Virgin Classics 5 45589 2). The sound was enveloping and energetic as the male and female choruses hand off melodic settings of lines about the beauty of nature and national awakening. In their opening phrases, the female choirs’ delicate motifs have an ethereal quality. When the orchestral brasses enter, the H90 revealed no congestion in its sound and demonstrated its mastery of dynamic range. I then listened to this recording through level-matched Grado Labs SR80 headphones, and found that their lessened detail and narrower dynamic range didn’t do the Hegel justice. The differences between the SR80 and HE-500 headphones were much more dramatic through the Hegel H90 than through my NAD C 356BEE.
Value and wrap-up
Hegel Music Systems maintains its well-deserved reputation for producing high-quality components with the H90 while bringing that quality down into the budget market. The H90 provides a balanced set of features that includes proven technologies and can integrate with equipment already on the buyer’s rack. In my time with the H90 I found nothing that it did wrong -- just a few defensible choices. This was my first experience with the Hegel sound in my home system, and I appreciated their minimalist philosophy of “do no harm,” in which the electronics get out of the way of the music. Including the SoundEngine technology of upmarket Hegel models, the H90 punches well above the level you might expect from a DAC-integrated at its price -- Hegel’s attention to dynamics, detail, and transparency shone through. The Hegel H90 is well worth hearing.
. . . Sathyan Sundaram
- Speakers -- Sonus Faber: Principia 3 and Principia C; Wharfedale: Diamond 8.2, Diamond 8 Centre, PowerCube 10 subwoofer; Infinity Primus P162
- Headphones -- Grado Labs SR80, HiFiMan HE-500
- Analog sources -- Goldring GR1 turntable, Rega Research RB100 tonearm, Goldring Elektra cartridge; Onkyo TA-RW244 tape deck
- Digital sources -- Music Hall MMF CD-25 CD player; Pioneer DV-563A DVD/SACD/CD player; Google Chromecast Audio; Raspberry Pi2 running volumio 2.246; Monoprice HDX-401TA; Apple iPad Pro
- Subscription services -- Google Play Music All Access (via Chromecast Audio)
- Phono preamplifier -- Cambridge Audio 540P
- Integrated amplifier -- NAD C 356BEE with MDC DAC 2.0 module
- Power conditioner -- APC Line-R LE1200
Hegel Music Systems H90 Integrated Amplifier-DAC
Price: $2000 USD.
Warranty: Two years parts and labor.
Hegel Music Systems AS
PO Box 2, Torshov
Phone: +47 22-60-56-60
Fax: +47 22-69-91-56