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Audio Reveal

Manufacturer: ALTRONIK
Price (when reviewed): 46 900 PLN

Contact (for Europe):
ul. Muszlowa 3 lok. 83
01-357 Warszawa ⸜ POLAND


Provided for test by: NAUTILUS Dystrybucja


Images by Marek Dyba, Audio Reveal

No 240

May 1, 2024


AUDIO REVEAL is a Polish brand specializing in the design and manufacture of single-ended tube amplifiers. However, the latest product of this company, that premieres herewith, belongs to a different category, although familiar elements are still there. It is the latest product in the lineup, the Hercules DAC, which belongs to the rare genre of tube DACs. What's more, it features the magical 300B triodes.

THE ALTRONIK, OWNER OF THE Audio Reveal brand, was established in the historic (for our country) year of 1989. For 26 years, however, it had virtually nothing to do with the audio industry. That is, except for the private passion of its owner MICHAEL POSIEWKA. It was he who in 2015 came up with the idea to develop his own tube amplifier, preferably with a single ended output stage. The idea resulted in the first commercial product in 2018 proving right from the start of the new endeavour, it is not in this designer's nature to rush development of new products.

Audio Reveal was chosen as the brand name for audio products, as its creator intended for products with this logo to reveal to users new layers of information and emotions encoded in musical recordings. That first model was simply called → FIRST, as it came first (test of the Mk II version → HERE), the next, you guessed it, was named → SECOND, and later came its → SIGNATURE version, as well as the opening model → JUNIOR.

For its partner on both, Polish and international markets, Audio Reveal chose an experienced distributor, Nautilus from Krakow. Let's add that all products of this company had their premieres on the pages of "High Fidelity" magazine.

Audio Reveal x 4

As I’ve mentioned, the following years brought the release of successive models of Audio Reveal integrated amplifiers. Each of them was based on the same design assumptions. First of all, all devices were based on tubes, and these were supported by a high quality power supply and high-end output transformers (which, in this type of design, are the most important elements for the sound quality). Secondly, the external design remained unchanged (except for minor elements), with a wooden front and metal components, so that all it took was one look to recognize the brand behind every new Audio Reveal product.

Thirdly, the tubes in the output stage each time operated in single ended mode. Fourthly and finally, although it would seem that the obvious choice for such designs would be triodes, you couldn’t find them in any of the recalled models. The 6550 in the Junior, the KT88 in the First (also Mk II), the KT150 in the Second and the KT170 in the Second Signature were not the obvious choices, but, as listening tests proved, the designer was right to chose them.

As you probably know from your own experience, or from our (or any) reviews, each of these amplifiers, even the opening Junior offering, offers great, mature, refined sound. The choice this particular, rather than any other, type of the output stage results in yet a fifth, distinctive feature. Each of these designs offers relatively low output - for the Junior it's 10 watts, and for the Second Signature, the most powerful of the bunch, it's 21 watts per channel. You should also know, that since power supplies in each model are of very high quality each of Audio Reveal amplifiers can surprise you with it ability to drive speakers that on paper seem to difficult for low-power amps.

Audio Reveal, as I suggested at the very beginning, has never been a company that throws at us new quickly-designed products just to keep some schedule or to present a novelty at each show. It always takes a long time to design, develop, build, test and tune each new project. The work stops only when Mr. Posiewka is fully satisfied that the product meets his standards and particular assumptions, and that takes time. Yet, the lineup grew to five amplifiers, which is already quite a lot, and which is probably why the previous latest Second Signature model was followed by a slightly different, though logical addition to the range.

As Michał told me, the idea of creating (for a change) a DAC popped out nearly two years ago. It was indisputable from the beginning that it would be a D/A Converter with a tube output stage. It was also very quickly followed by the assumption that this time, as if in contrast to amplifiers, it would feature triodes. In conversation with me, the designer also admitted that he immediately thought that for this device he would rather use one of the older multi-bit DAC chips, which he particularly valued, as did many others, for its unique, musical sound.

After testing several of them he chose the one that he thought offered the sound closest to his idea of what the device should sound like and.... decided not to share specific information regarding his choice. The markings of the chip have been removed, so even the more persistent ones who will peak under the hood will not be able to check manufacturer and model. This was the designer's intention - it is the performance of the DAC that should help potential customers to choose this device, and not a list of components used to achieve the sound.

Michał also admitted to me that he's not a big fan of the DSD format (i.e., he doesn't hear its advantage over PCM), so the selected chip didn't have to support, and it doesn't, this format. Ultimately, Hercules is a tube DAC with the magical 300B triodes on board (although the first prototype used dual 6SN7 triodes, and it was only in the course of development that they were replaced by 300Bs, which Michał found sounding even better, more to his liking), supporting hi-res files, but only those in PCM format.

Is that a downside? Hardcore DSD fans will probably say yes. I myself, an ardent supporter of it, after successive upgrades of my LampizatOr Pacific DAC (now in version 2), at some point stopped paying attention in my daily listening routine to whether I play DSD or PCM files, because both sound equally good. So, in my opinion, at least for people who use software such as Roon (which offers an option to convert unsupported formats/resolutions to those supported by a given DAC), this is not even the slightest problem.

The DAC has been christened with the mighty name of Hercules, and had its premiere in March this year during an event held at Nautilus headquarters in Krakow, which I had the pleasure of attending. Two units of this device played in two separate rooms and systems. The first was equipped with tubes supplied as standard with the unit, while the second showed what a possible upgrade with the help of Emission Labs' excellent tubes could offer. The distributor provided both DACs with suitable company consisting of choice components from brands such as Accuphase, Dynaudio, Ayon, Siltech and others.

I must admit that Hercules made quite an impression on me. That's why a week after the official premiere, one of the units and two sets of tubes visited my listening room.


FOR COMPANIES THAT DO NOT BELONG to "mass-manufacturer" category, and Audio Reveal surely doesn’t, one of the ingredients necessary for success is a reasonable approach to production process. What do I mean? A solution is developing a distinctive, visually attractive external design and sticking to it whenever possible when creating subsequent products. Second solution that helps is using the very same (or very similar) elements/components in various models which allows a manufacturer to purchase larger quantities which in turn translates into a lower purchase price and, on the other hand, more flexibility when it comes to fulfilling orders.

This is why all Audio Reveal amplifiers to date have used similar, albeit different sized chassis. When it came to creating the DAC, one of the first assumptions was to use the chassis developed for the First. The Hercules was originally developed on (a piece of wood", that is, without any chassis, so it initially seemed that a chassis of this size would suffice. When the circuit was ready, however, it turned out that it wouldn’t quite fit in, also because several components needed enough space around them for proper ventilation. It is a tube device, after all, and as such it emits a lot of heat.

Michał told me that it would probably be possible to use a smaller chassis, but that would mean operating the components, including capacitors, at temperatures that would shorten their lifespan. Therefore, Hercules shares a chassis with the larger Second amplifier which this means that we are dealing with an amplifier-sized device, weighing a little less than Second (about 16 kg), but still heavy for a DAC.

The use of the same chassis suggests that Hercules will look really good next to any amplifier from this brand. At the same time, it is simply an elegant component with a distinctive look, with a Merbau wood front panel (although it is possible to order the Hercules with a black stained panel) and two steel knobs. The left one (when viewed from the front) is the unit's on/off switch, and the right one is the input selector. The entire chassis, made, as in the case of the amplifiers, of bent steel sheet powder-coated in black, is set on anti-vibration feet.

The designer, looking for one of the key components, a digital-to-analog converter chip, went for the ones he himself prefers, that is, older multi-bit designs. As I mentioned, he does not share information about his ultimate choice, and has even taken steps to make it impossible to check by the markings on the chip itself. From the choice made, however, come the capabilities of the Hercules, which supports playback of the PCM format at resolutions up to 24 bits and 384 kHz. It features an USB input (supporting up to 24 bits and 384 kHz), and two coaxial and one optical Toslink inputs (these accept signals up to 24 bits and 192 kHz). So we have four digital inputs at our disposal and one unbalanced (RCA) analog output. The set of connectors on the back panel is completed by an IEC power inlet.

As Michał told me, PCM in his opinion sounds so good with his DAC that DSD support was simply not necessary in this case. At the same time, he realizes that DSD has its avid fans, and therefore there is a good chance that in the future also lovers of this format will get a chance to use it with Audio Reveal DAC. Whether it will be offered as an upgrade for Hercules, or only in the next planned converter - we don’t know for now. To provide DSD playback it will be necessary to use a different DAC chip, although it will certainly be paired with a tube output stage.

I mentioned earlier that the size of the enclosure is due to the fact that it was necessary to provide the components with proper working conditions so that they could operate reliably for many years. The selection of these components was based on both their quality, reliability and listening tests. Among them were Clarity Cap and Nichicon capacitors, for example, while the transformers and choke came from a Polish specialist, Mr. Leszek Ogonowski.

The output stage is not the only „tube” section of Hercules, as the power supply is based on a tube as well, specifically a 5U4G rectifier. This is another, after the final choice of 300B for the output stage, good news for fans of tubes, as there are quite a lot of both on the market (new and NOS), which offers Hercules users the opportunity to shape (to some extent) the sound of their device. For this DAC manufacturer chose Russian NOS 5U4G rectifier, while the 300B pair comes from PSVANE - this particular version is "UK Design".


HOW WE LISTENED • The Audio Reveal Hercules digital-to-analog converter was tested in my reference system replacing in it one of the best DACs available on the market and, importantly, also a tube device, LampizatOra Pacific 2.

The source of signal for the USB input was my custom passive server running the latest version of Roon equipped with a JCAT XE USB card powered by Ferrum Hypsos in Signature version. Server and DAC were connected using David Laboga Custom Audio Expression Emerald Mk 2 cable and further via a Soyaton Benchmark analog interconnect to, interchangeably, a GrandiNote Shinai integrated and Circle Labs split amplifier (P300 + M200). The latter two components were connected using KBL Sound Himalaya II balanced interconnect. The amplifiers via the Benchmark speaker cable drove, interchangeably, my GrandiNote MACH4, but for some time also Fonica International FLAG L planar speakers.

Testing was divided into three stages using three different pairs of 300B triodes: standard tubes from the Chinese company Psvane, tubes from the Czech manufacturer Emission Labs, and American Western Electric tubes.


Hercules + Psvane

LET’S BE HONEST, AUDIO REVEAL HERCULES is quite an expensive device, albeit it is a matter of perspective, because compared to my LampizatOr Pacific 2 it seems to be priced very moderately. In other words, despite its high price it still costs only a fraction of what the manufacturers of the most expensive DACs ask for them. But with its price, which is hard to disregard (once you know it), when testing it you have to set very high expectations for it. For the test I got it with two sets of tubes, the standard ones and those intended as a potential upgrade that come from Emission Labs, so by design, as it were, I spent most of the time listening to the „standard” version, only later „upgrading” the DAC with Emission Labs tubes, leaving a pair of my own Western Electric 300Bs for dessert.

My impressions from listening to the two refined, but nonetheless for me (at least as whole) non-familiar systems at Nautilus were more than good, but listening to it in my own familiar setup was something else. The impressions from my setup, even the very first ones after firing up the "cold" Hercules, were simply much more credible. And, to be honest, they were at least as good from the start as those remembered from the Krakow’s premiere. The key word describing Hercules right from the start? MUSICALITY!.

I know that from any 300B tube DAC being „musical” is theoretically what should be expected if not demanded, but I also use 300B tubes in my Pacific 2 at times, and while its musicality in undeniable, it is not the most prominent quality of it sound. Audio Reveal's musicality entails a number of effects, starting with fully engaging listeners. It is not, except perhaps for very quiet playing, a DAC that can play music in the background, although that depends a bit on the repertoire. For me, whenever acoustic music or vocals started, they drew my attention like a magnet even when I was supposed to do something else, something important. Music, through recordings and playback systems, is supposed to first of all move listeners, just like the one played live, it is supposed to evoke some reaction, some emotion. And this is what Hercules is good at, very good, even great! It never leaves listeners indifferent.

It didn’t when I listened to KEITH JARRETT from his solo concert in Koeln, or when each piece from Pink Panther & Friends played on, that is, jazz variations on a famous theme from a well-known film, or when the sounds of bamboo instruments from JOHN KAIZAN NEPTUNE's Asian Roots album came from the speakers. All of these presentations had many things in common. First of all, the incredibly natural, true (as far as someone who was not involved in the recording can assess it) sounding timbre of the instruments, the depth and saturation of the sound, its openness and airiness, the perfectly rendered acoustics of the recordings both live and studio ones. Plus, the not overly exposed, as if a bit subcutaneous, but highly impressive energy of the reproduced sound.

Jarrett's piano "breathed", sounded dynamic, and the noises coming from the hall made the presentation even more credible. Even in studio recordings, however, there was considerable space around the instruments, which (even if at least in part added to the recording, not „natural”) participated in the creation of the music, and was an integral part of it. The reverb superimposed on both FAUSTO MASSOLELLA's guitar and GENNARO DELLA VOLPE's voice in one of the tracks was shown by Hercules in such a way that it was hard to resist the impression that their performance was recorded in a huge room. What really mattered, however, was how all these elements worked together combining into an extremely coherent and seamless whole. A whole that was impossible to remain indifferent to, one that resonated with me, that was fabulously natural and incredibly.... MUSICAL!

It is not, however, a musicality that comes from coloration of the sound applied to make it more appealing to the ear. Yes, the Hercules' sound is warm, but naturally warm, not warmed up. It's devoid of sharp edges, at least as long as material doesn’t clearly demand it (like when Al di Meola’s guitar came on on one of his albums, which was supposed to pierce ears a bit, and that's exactly what it did), and it's dense, but this characteristic is also part of the sound being „natural”. How could I tell it was natural „density”? Simply because the density in question was a result of the great resolution of this DAC which filled the sound with huge amount of information. Another clue was the fact, that the tested DAC, with all its density and smoothness, at the same time offered an easy insight into the deeper layers of recordings, sounded pure and transparent, and while I could easily point out a lot of tiny details in the sound it wasn’t one I would call „detailed”. All those details were used by Hercules to enrich the whole, not to impress a listener by their mere, artificially emphasized, presence.

To hear all that you don't need sophisticated acoustic recordings at all, because even the aforementioned album by the guitar master, Land of the Midnight Sun is by no means the eighth wonder of recording technology. Nonetheless, with Hercules, I was offered an abundance of information sourced from these recordings, and presented in a way that forced me to focus solely on the music, its intensity, energy, tempo and rhythm, and not on the somewhat muffled, and sometimes bit harsh treble (this is a matter of recording, not playback!). The same thing happened when I listened to STEVE RAY VAUGHAN. Quality of his recordings is mostly good, but not necessarily quite at the level most demanding audiophiles expect. For what it's worth, the music is fantastic, and SRV's guitar playing style has become an inspiration for many younger blues, and rock guitarists.

With Audio Reveal’s DAC, the minor recording or release imperfections simply landed somewhere in the background, almost at the edge of perception, behind the music, behind this incredibly energetic performance brimming with emotion. The master's guitar had everything it should have - it was properly „fleshy”, aggressive and sharp, when needed, it had a punch, but it was also presented in a suitably precise manner allowing one to appreciate the extraordinary talent of the artist. And my impressions were equally good when listening to Slash (with Guns'N'Roses, or with MILES KENNEDY and CONSPIRATORS), whose concert with the latter band will take place in Katowice on the day this review is published (and I shall be there!), Angus Young (AC/DC), or Joe Perry (AEROSMITH).

With the basic tubes, there may have been a hint of a „romantic nature” in the playing of each of these guitarists, but there was nothing lacking in terms of that fantastic energy and a touch of rawness that characterizes rock guitars. The sometimes annoying sharpening in the upper range was slightly less annoying with this DAC than with most similarly priced (and even some more expensive) solid-state DACs, although I know exceptions also among the latter (Weiss Helios, or Playback Design MPD-6, which I had the opportunity to test recently, to name just two). This proves that the Hercules (with these tubes) gently smooths out the upper part of the band, but does it really sensitively, thus enhancing the listening pleasure of such imperfect recordings without significantly changing their character.

In fact, I already liked this basic version of the Hercules so much that I was not at all in a hurry to change the tubes for "better" ones. It sounded natural and very "analog" (this is a note to vinyl record lovers - you will most likely like this DAC a lot). Also, compared to the Pacific 2, it performed really well, even if the latter is even more resolving, transparent and precise, and therefore a bit more (naturally) neutral. So the difference, as it usually the case is in audio, was not directly proportional to what a simple price comparison would suggest.

The aforementioned solid-state DACs, which I recently had the pleasure of testing, are also representatives of a significantly higher price range, and also, with their outstanding musicality and naturalness of sound, belong to the category of even more precise and neutral sounding DACs than the Hercules. Despite their certain "audiophile" advantages, the new Audio Reveal joins them and literally two or three other, mostly much more expensive (than the Hercules), DACs, whose presence in my system instead of the LampizatOr I could live with, and which would not spoil my pleasure of listening to music. It is simply a damn good DAC!

Hercules + Emission Labs

300B TRIODES ARE among my favorites, although I had the opportunity to listen to them far more often in amplifiers than in DACs. My experience with the former was not at all always clear-cut, i.e. not always replacing tubes with theoretically better ones gave the desired results. The ironclad example I almost always refer to was the Wavac amp with factory installed JJ tubes. It sounded really good, even surprisingly good with them. I remember that when I finally swapped the Slovakian tubes for my Western Electrics in some respects I heard some improvement, but the presentation as a whole turned out to be less coherent, less complete so ultimately I returned to JJs. This is why I am cautious about claims that simply replacing the tubes with better ones (which usually also means a lot more expensive ones) is enough to guarantee a dramatic improvement in performance. One should always check such option preferably though, before spending money on „better” tubes first.

At the time aforementioned Hercules premiere at Nautilus, we could listen to this DAC with two different sets of tubes, but also in two different systems, so it did not really offer a chance for a reliable comparison. This time, however, I could listen to the DAC with one set of tubes, then turn the device off for a few minutes, swap tubes, wait a bit until the new ones achieve proper temperature (i.e. about 20-30 minutes), and... I could listen to the same tracks again looking for possible differences resulting from a different tube set. These, of course, are also not the optimal conditions for comparisons, but other than having two Hercules with two sets of tubes placed one next to the other, it was the best I could do.

So, what did I find out? With the Emission Labs tubes Hercules lost a bit of the romantic nature or sweetness of the top end. The latter, though still fabulously natural, open and vibrant, became a tad harder, a tad more contoured, which could also be heard in the other band extreme, where the bass became tighter. The presentation as a whole lost nothing in terms of smoothness and coherence, gaining instead in terms of precision and transparency of presentation. To put it briefly, it was presentation closer in character to the one I know from the LampizatOr Pacific 2 (where I also use the Emission Labs on a daily basis, but PX4s). The leading edge of sounds, and the contours of the instruments were slightly better pronounced, the better insight into the deeper layers of the stage and improved precision of imaging were another attributes added by Czech tubes. These were not big changes, but they were exactly what you would expect when replacing tubes with "better" ones.

So, going back to the question from a few paragraphs ago, let's ask: so is it worth replacing the tubes in the Hercules with more expensive ones? The answer, as it is common in audio, is not at all clear-cut. This slightly more romantic, slightly sweeter sound with the Psvane tubes has its charm, especially when it comes to acoustic and vocal music. The presence of the performers is built more by the density of their images than by a precisely defined contours, the timbre of the instruments and the emotions captured in the recordings play a bigger role. Also, the decay of instruments with these particular tubes seemed a tad more natural to me, and the acoustics of the recordings seemed to play a slightly larger role where the Czech tubes focused on accurately capturing the sound of the instruments themselves.

However, if one were to take a checklist with generally accepted characteristics that a high-end audio device must deliver on, one would probably tick off a few more boxes for the Hercules with Emission Labs tubes, simply because it offered more „audiophile”, more faithful presentation to the nature of the recordings. The choice, however, will depend on individual users and their preferences. I, for one, am not at all convinced that I would bet on Czech tubes when choosing between these two sets, at least if listening pleasure was the ultimate goal. However, as a reviewer's tool for evaluating other system components, the Hercules with Emission Labs tubes would do a better job.

Hercules + Western Electric

I COULDN’T HELP MYSELF and „for dessert” I had to at least briefly listen to the tested DAC with my, already a bit worn out, but still great-sounding Western Electric tubes. With them I got a sound that was a bit more precise and refined than the Psvane, but at the same time a bit sweeter, more palpable than with the Emission Labs. For me, they were a kind of golden mean, that allowed me to immediately forget that my job was to evaluate the sound. Instead, I just let myself be carried away by the music.

Soon, I found myself focused on listening to good live albums, and actually more for pleasure than out of obligation, I listened to titles by MUSICA NUDA, PATRICIA BARBER, HADOUK TRIO, or CHRISTIAN MCBRIDE's band recorded in small clubs. There is something special, unique about this sound offered by properly used (because it is all about application) triodes, and particularly 300Bs. With hercules there was this extraordinary naturalness, this feeling of participating in an event instead of just listening to its recording. There was excitement, goosebumps and a smile on the face. It sounded so good, so immersive, that I was not at all in a hurry to return to my Pacific 2 DAC, even though it is, after all, an higher quality, better device. The Hercules, however, somehow made me not think about it at all. And that's not an easy task and happens extremely rarely with other DACs.


AUDIO REVEAL HERCULES may seem like a device from a slightly different time. After all, on the outside we see a wooden front, tubes, no trinkets, no bells and whistles, or in a word a typical "old-school" tube device. The set of inputs and outputs isn't the most impressive either, but it's really enough to satisfy the actual needs of 95% of potential users. The designer made some choices, because the goal was not to achieve maximum versatility or functionality, but the best possible (for a given project) performance. Instead of studying the appearance or the description of the Hercules' capabilities, one should simply give it a chance and listen to what the designer managed to achieve sound-wise with the truly magical 300B tubes and the not-so-modern DAC chip. There is a strong chance that after you do that, you will get to the same conclusion as I did - "I don’t care about those „downsides", because what truly matters is the performance”. For me the class of this device is not even in question, it is simply a high-end DAC!

Its sound is smooth, natural, vivid, open, highly energetic, saturated, dense, and at the same time (depending on the tubes) also a bit romantic and incredibly MUSICAL. And the result of all these features combined is that listeners easily get engaged, immersed in genuine experience while listening one album after another with a smile on their faces. Because this is the kind of device that is supposed to draw the listeners in, move them and give them immense pleasure while experiencing music, and not serve as a tool for taking recordings apart. Importantly, what it does, it does with real class! Congratulations Michał on another fantastic product! From us a fully deserved ˻ RED Fingerprint ˺!

Technical specifications (according to the manufacturer):

Tube complement (included): 2 x 300B (PSVANE) 1 x 5U4G
Frequency range: 20 Hz-20 kHz (+0 dB, -0,2 dB)
Digital inputs:
• USB supports: PCM 44.1 ⸜ 48 ⸜ 88,2 ⸜ 96 ⸜ 176,4 ⸜ 192 ⸜ 352.8 ⸜ 384 kHz, 16 ⸜ 24 bits
• 2 x RCA supports PCM 44.1 ⸜ 48 ⸜ 88,2 ⸜ 96 ⸜ 176,4 ⸜ 192 kHz, 16 ⸜ 24 bits
• Toslink supports PCM 44.1 ⸜ 48 ⸜ 88,2 ⸜ 96 ⸜ 176,4 ⸜ 192 kHz, 16 ⸜ 24 bits
Analog output: unbalanced, RCA
Output voltage: 2.7 V
Startup time: 60 s
Nominal power consumption: 95 W
Dimensions (W x H x D): 476 x 410 x 220 mm
Weight: 16 kg

THIS TEST HAS BEEN DESIGNED ACCORDING TO THE GUIDELINES adopted by the Association of International Audiophile Publications, an international audio press association concerned with ethical and professional standards in our industry, of which HIGH FIDELITY is a founding member. More about the association and its constituent titles → HERE.