The machine:

Conceived and built by Audionet`s legendary scientists and engineers, HUMBOLDT shares all the unsurpassed qualities of his brethren STERN and HEISENBERG, winners of the most coveted high end awards during the last three years. The design by German industrial designer legend Hartmut Esslinger hiding the most advanced circuitry and technology money can buy in today`s highenddom, HUMBOLDT stands as an integrated amp unlike any other on this planet. Our HUMBOLDT is the namesake of famed polymath, geographer, naturalist and explorer Alexander v. Humboldt who resurrected the use of the word cosmos from the ancient Greek and assigned it to his multivolume treatise, Kosmos, in which he sought to unify diverse branches of scientific knowledge and culture.This important work also motivated a holistic perception of the universe as one interacting entity.Thus aptly named, Audionet`s HUMBOLDT explores the universe of music and leads us to discoveries unheard before. Enjoy the ride!

The science:

Special features HUMBOLDT

  • Double mono layout of all circuitry and power supply for maximum channel separation.
  • Magnetically and capacitively optimized circuit and device design without any ferro-magnetic materials.
  • Floating Pane Design for optimal resistance against microphonic effects and temperature stability.
  • The floating panels of the body are resonance-optimized by pads on an aluminum frame.
  • Mounting and bolted assembly of transformers made of stainless steel.
  • Air Flow Design circuit boards for an optimum of cooling and stable quiescent currents.
  • Galvanic separation of all analog circuits by opto couplers.
  • Rhodium RCA inputs and mains connector by Furutech.
  • Volume controller on a double ball-bearing axis and with magnetic ratchet and optical sensing.
  • DC coupled with no sound diminishing capacitors or coils, shortest signal paths.
  • Four power supplies for positive and negative power currents, separate for input & driver stage and power stage.
  • Two encapsulated und decoupled 100VA and two encapsulated and decoupled 850VA toroid transformers.
  • Low impedance-optimized power capacitors with a total capacitance of 312.000 µF.
  • Total capacitance 400.000 µF.
  • Newly developed contextual operating concept.
  • By-Pass mode for integration into home cinema systems..
  • Audionet Link outputs for the remote control of further Audionet ULTIMATE SERIES devices.
  • Microprocessor control with separate power supply monitor and control of all functions, informing the user on a high resolution display.
  • User definable names for each input, input levels adjustable for each input.
  • User selectable function to remove DC levels from signal sources.
  • Rhodium fuse.
  • PreAmp Outputs in RCA and XLR for connecting additional Power Amps.



Microprocessor controlled Ultimate Linear Integrated Amplifier


In- and Outputs

Inputs: 4 pair Cinch line, Rhodium (Furutech) 2 pair XLR balanced, gold plated (Neutrik) 1 D Sub 9 serial port (control only) 1 SMA for WLAN (control only)
Outputs: 2 pair Cinch line, Rhodium (Furutech) 1 pair Cinch inverted, Rhodium (Furutech) 2 pair XLR balanced, gold plated (Neutrik) 2 Audionet Link, optical 1 connector, gold plated, for additional earth connection


Technical Data

Typ Ultimate Analog Integrated Stereo
Amplifier Output Power 2 x 320 W into 8, 2 x 460 W into 4
Frequency response: 0-700.000 Hz (-3 dB), DC 0,3-700.000 Hz (-3 dB), AC
THD+N <-100 dB @ 1 kHz
SNR > 120 dB, (A-weighted)
Channel Separation >140 dB, 20-20.000 Hz
Input impedance: Cinch (Line): 50 kl
Symmetrical (XLR): 35 kl
Mains: 220…240 V or 110…120 V, 50…60 Hz
Power consumption: < 0,5 W Stand By, max. 1800 W
Dimensions: Width: 450 mm
Height: 320 mm
Depth: 505 mm
Weight: 61 kg
Finish/Colours: Corpus: Aluminum, 9 mm, Silver or black Display light or dark Colour TFT
Display: Colour-TFT
Finish Corpus: Silver or black, Display: Light or dark colour TFT


The Absolute Sound

„When it comes to soundstaging and imaging, Humboldt is truly world-class. Not only was the stage compellingly wide, deep, and most notably, of proper height, but image sizes were completely realistic, with solid and stable locations, and a get-up-and-walk-around-in dimensionality. This was demonstrated consistently, with every genre I played, from classical, to classic rock, to the blues.

From the lowest register to its uppermost extensions, the Humboldt displays a remarkably consistent, unwavering tonal balance, which, when combined with its exacting speed and dynamic prowess, yields one of the most credible senses of tempo, pace, and drive imaginable.

The Audionet Humboldt is one utterly enchanting machine. My notes for this audition repeatedly mentioned two sonic attributes more frequently than all others…tone and texture. Its ability to render low-level textural, transient, and timbral details in such a complete and holistic manner allow the Humboldt to let any music it recreates flow with heightened nuance and immediacy. As a result, voices are at once more natural sounding, purer, and more expressive, bringing you that much closer to the artists intended message.“ (Greg Weaver)


Audio Activity (Italy)

„Finally, what should I add? First of all, I feel a little guilty to you for using so many exaggerations, you know that this is not my style, but I couldn’t describe the emotions that the Audionet Humboldt triggered in me any other way.
What amazed me most was his ability to materialize voices and instruments in three dimensions, with an impressive absence of grain or electronic artifacts.
Do you know the difference between looking at a landscape on a postcard and experiencing it live? Well, after listening to this amp well, the rest of it sounds like postcards to me.
It’s a top notch performer who doesn’t add anything of its own.
Personally, I have never listened to anything like it, under so to speak “controlled” conditions.
We are really on another planet.“ (Angelo Jasparro)


STEREO (Germany’s leading HiFi magazine, English version)

Weaknesses? – Not a single one!
We listened for a long time and looked to see if we could find a, possibly even bad, compromise at any point – but we did not discover even the slightest one in our search. From today’s point of view, the concept of this amplifier, which is consistently handcrafted by a specially trained Audionet employee, seems to us to be absolutely flawless. The Humboldt is positioned above any possible criticism, it simply does not show any weakness. Those who can afford it and have so far considered spacious pre/power amplifier combinations in order to reach the sonic nirvana may need to rethink. From now on, even the best separate amplifier combos have a serious opponent in this milestone from Berlin. However, it is withdrawn from a classic rating in view of the price tag.


AUDIOreview (Italy’s leading HiFi magazine, Italian version, sorry)

In qualsiasi ambito commerciale esistono prodotti di punta realizzati in piccoli nu- meri e con la cura che solo una manualità esperta e guidata da una visione ben chia- ra degli obiettivi può garantire. L’Audio- net Humboldt rientra ampiamente in questa categoria elitaria, ed offre presta- zioni oggettive che di certo non si riscon- trano con frequenza. Rapportare queste ultime al costo, che qui è prossimo a quel- lo di una Classe C Mercedes, permette so- lo di ottenere un numero privo di senso per quei facoltosi che una volta visto ed ascoltato un amplificatore di tal fatta se ne innamorano perdutamente. (Fabrizio Montanucci)


(NOTE: While HUMBOLDT is being reviewed by the leading German and international magazines, this section features the test reports on his brethren STERN and HEISENBERG, too. Apologies for any inconvenience, but hey, it’s the ULTIMATE series, so this is just a family affair. You may deduct a few percents from the prose herein for yourself, reflecting that obviously much larger reduction in price. Thank you, much obliged.)


AV Showrooms

Product of the Year + Gold Award by AVShowrooms for our statement Amp HEISENBERG. It doesn’t get better than this in the High End, guys. Thank you!!!


Stereo Times

“The bass was quick-footed, articulate and most importantly it conveyed a musicality that belied both its size and build. All I could say was DAMN! Ironically, instead of more powerful, the system appeared more relaxed and resolving – as if the added wattage aided in providing less stress and more realism. In a sense, it sounded as though the Heisenberg/Stern combo took full control of the massive YG XV’s many individual drivers and made them a single source.

The very look and feel bespoke “state of the art” throughout while the sound is powerful and taut, yet elegant and ultra-refined. Voices hover above the floor at the right height and size but elicit a sense life that’s quite uncanny for a solid-state design. Music just flowed into this huge listening space in way that it had not in the past. It made the room seem smaller and more intimate. Weird. This made it somewhat difficult to concentrate on anything except the music. What higher accolade is there when a system can achieve that?

I don’t know what else to say except that listening to the Audionet Heisenberg and Stern combination was truly an adventure!”
Stereo Times, Clement Perry


the absolute sound

“We chose to listen exclusively to LPs for this audition. I got to spend the entire day listening to this remarkable system, and virtually every LP we played (I had a dozen of my own favorite records with me) left me astounded. From the moment the needle landed in the groove, the utter naturalness of the presentation became apparent. I was hearing subtleties of hall and performance ambiance that I’d never before heard in all my years of listening to this LP on literally hundreds of systems. Transients were crisper, more sharply and accurately delineated, tone color and texture were astonishingly accurate, and every aspect of the presentation was depicted with full, honest bloom, accurate weight, and ample body.

Dynamic scaling was spectacular, and I was overwhelmed by the degree of ambient detail conveyed. The way this system recreated the sound of a snare drum—its location, size, tone, body, and retort—was chilling. This system expressed a fine degree of delicacy and finesse that I’d never experienced prior, and yet, at the same time, there existed an enhanced measure of power and speed. Both of these characteristics coexisted in equal measure; neither showed compromise.

An absolute revelation of the musicians’ spatial relationships within the soundstage and of vibrant, faithful timbre. And the rhythmic pace, the timing and drive of the music, had never sounded more frenetic!

During my time in front of this system, my impressions about a number of attributes that this new linestage and monoblocks demonstrated solidified. One was the overwhelmingly conspicuous absence of any vestige of transistor pall, glare, or grain. Moreover, all instruments, both in their singular, individual voices and in their specific locations throughout the soundstage, had never been so starkly apparent and yet so convincingly natural sounding.

Add to this the expressive and seemingly unflappable sense of unrestricted power and control, and you have a series of electronics capable of recreating a sense of realism unprecedented in my experience of three-plus decades of reporting on the art of music reproduction.

The Stern preamp and Heisenberg monoblocks push the bar to previously unattainable levels.

In short, the combination of the Audionet Scientist Series Stern and Heisenberg monoblock amplifiers establishes a new benchmark.”
the absolute sound, Nov 13th, 2017, Greg Weaver



“What is more, low-level textural, transient, and timbral details were rendered in a more complete and holistic way and with a heightened sense of focus and nuance. As a result, the voices of instruments and human singers became at once more natural sounding, more pure, and more focused. The sheer effortless clarity I heard was unlike anything I had heard from any hi-fi system in the past, and as a result, large-scale choral and orchestral works took a quantum leap forward in overall intelligibility and lucidity. Even more depth, more focus, and much more bass detail, yet that is exactly what the Stern/Heisenberg electronics delivered. Third, (and perhaps this come as no surprise) the extremely powerful Heisenberg amplifiers (1,050 watts @ 4 ohms) gave the system a certain “ceilings unlimited” quality in terms of dynamics.

Now those raised in the ‘smaller-is-better’ ethos of hi-fi amplification might well wonder if blockbuster amps such as the Heisenbergs could be anything but muscle-bound, but that isn’t the case at all. In fact, I suspect the Heisenberg might just be the most fleet-footed and agile audio amplifier I’ve ever experienced. Two major benefits of the Stern/Heisenberg package are these: first, the strengths of ancillary components seem greatly magnified by the Audionet electronics, and second, with the Audionet components in play recordings can be explored in much greater depth and with more insight than listeners might have thought possible.

In case you’re wondering, I’m not the only one who finds these components beautiful; in fact, the Stern is now on display as part of the Smithsonian’s National Gallery.

The bottom line is that Stern and Heisenberg have, in my opinion, raised the performance bar for high-end audio electronics, and I say this having heard top-tier components from Audio Research, Constellation, Dan D’Agostino Master Audio Systems, Naim Audio, Pass Labs, Soulution, and others). They also serve admirably as audio objets d’arts that are, in a very literal sense, of museum quality. Therefore, I would encourage listeners to go hear and see the Audionet components, if only for a glimpse of what’s possible when performance constraints are removed.”
Hi-Fi+, Nov 08th, 2017, Chris Martens


Positive Feedback

“The Stern and Heisenberg have a serious, we’re-not-playing-around, visual that will stop you in your tracks with their scale, cosmetics—and ambition! Both units are encased in nearly identical aluminum chassis of flawless German metalwork (by German design legend Hartmut Esslinger). The Stern has already been placed in the Smithsonian’s National Gallery of Art. The Stern has got to be one of the largest preamps on the planet. Why so much real estate? I was told the interior is chock-a-block with circuitry. It boasts some amazing specs. There’s more: more tone, more timbre and, most especially, triumphantly, the grandest dynamic peaks I’ve encountered in residential audio. I’m always fiddling with or critiquing tonal balance—it’s rare to find a system that leaves me with no complaint—but with this rig I didn’t want to change a thing. The tone was BIG, with 100% saturation, and striking in its uniformity from top to bottom. The treble was sweet and extended, but never harsh, and certainly not of a quality I associate with solid-state. The mids were clean; the bass full, round and tight. All of uncommon purity. Yay! The tone showed no compromise. The instruments on The Blues and the Abstract Truth grew from ff like you get with other über components, and then pushed beyond that to full fff, where no amp has gone before. Edge-of-the-art for what’s possible in audio reproduction.”
Positive Feedback, Issue 94, Marshall Nack



“Stern and Heisenberg take the transistor amplifier to a new level. An ultimate position, a new benchmark. Most strongly recommended by Audiotechnique. … This Audionet system is ABSOLUTELY THE BEST OF TRANSISTOR AMPLIFIER TODAY, with the highest end performance.”
AUDIOTECHNIQUE magazine Hongkong, Editor-in-Chief Lincoln Cheng




“With the Stern preamp and the Heisenberg mono blocks, Audionet chimes in a new chapter of amplifier building. In more than one respect this trio is blasting conventions; sound quality and price fall definitely within. The attractive – also because it won’t reveal itself at first glance – styling by Hartmut Esslinger and the extent of innovative hightech from Audionet’s R&D department form in this triumvirate a passionate symbiosis which brought me a true joy of heart. The fact that these components bear the names of Noble Prize winners won’t cause any harm, for Otto Stern and Werner Heisenberg would certainly be proud to stand bail as namesakes for the new references.”




“Unheard-of-supremacy… A new leaf in the book of ampbuilding… Soundwise, musically and aesthetically the three towers are performing in a different league, a new class that needs no other superlative.”

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