Thrax Audio Dionysos preamplifier and Heros monoblock test review

Matej Isak

Well-Known Member
Jan 20, 2013
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Another rare ultra highlight of 2013 arrived. Rumen Artarski company Thrax captured my attention during the shows and getting to know their philosophy more deeply via their website and correspondence with Rumen. There was something so different and "right" about it that dragged my attention again and again toward their products and philosophy.


As I often stated, everything start from the first encounter; namely the shipping boxes, packaging etc. I really love when things are done right and in the best manner. Following wooden packagin further on, everything associated with Thrax product was refined and on the level I wish most companies would present them selves and their products. In ultra high end league, this is actually a must, but mostly fail to deliver. Why exactly? Dedication, pride of own works, respect for customers ...

Packing, manuals components design... All over achieved! Thrax Dionysos preamplifer aesthetics are a true piece of modern industry art. I always loved statement product in a state of the art enclosures, but Rumen really went far beyond ordinary in both inner and external design. High performance electronics executed electronically and visually in trueartisan way. This is a Thrax language of experssion.

Heros monoblocks are of the same calibre. With three dimensional looks and monument aura those are one of the best looking power amplifiers if not the best I'v seen! Period! And they sing!



Thrax Audio philosophy and approach strongly correlates with my inner clock and how things should be made according to my understandings and feelings about ultra high-end audio. From tube rectifiers, chokes, TVC's, best materials being used, simplicity of signal, remote, quality of build etc.

Here below are just three of their reminders and wake up calls to consider, but I strongly urge you to take time and go through Thrax Audio home page for their complete views. They are not there only to entertain, but they actually educate or reminds us on quite few important points:

Transformers. Why no body does that – and why they do only a partial job.

Transformers don’t measure that well. They have limited bandwidth and rising distortion at high levels and low frequencies. All those shortcomings are true, but would seem to be substantially better performing in dynamic conditions than ANY op amp. The effect is jaw dropping not subtle.

Why do we use triodes?

Audiophiles have been led to believe through published measurements at maximum output power and uneducated reviewers that single-ended triode amplifiers produce vast amounts of harmonic distortion. As a matter of fact triode vacuum tubes are by far the most linear amplifying devices in existence today. They produce the least amount of distortion, and that distortion is predominately second harmonic, which is the least obtrusive type for the sound. By contrast, pentodes produce greater distortion, and the third harmonic tends to dominate. A transistor looks at best like a very bad pentode.

Bring theory to practice – no feedback.

It is logical that a signal passing trough and amplification stage will have some distortion added to it. (In our case this will be almost only second harmonic.) Passing trough the next stage we will add distortion to the distortion generating a minimum amount of fourth order distortion and so on. (Pretty much like the effect of feedback described above)

Consider now the following: the usual preamplifier (tube or solid state) has 3 stages (input buffer, gain stage, output buffer), then the simplest power amplifiers have 4 stages (input, phase splitter, driver, output buffer ). And all this is dependent of the signal amplitude via an extremely nonlinear function.

In order to minimize this effect the preceding stage of any amplification stage should have at least 2-3 times lower distortion than the latter. (Would that be possible when we have 7 stages in the signal path?) Minimizing the number of stages reduces drastically the order of distortion and its inter modulation products.
The sonic result is vastly improved transparency and speed.

Our products feature the minimum sensible number of stages implemented with the most linear devices possible operating in the closest to theoretically perfect operating conditions achievable.

Result? You be the judge!

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All great artisans never hide their inspirations. Many of us share the respect for Japanese audio legends and their heritage. They did rewake the magic of tubes (Triodes) and approached the creational stage with their cultural norms. Those norms makes them so different and in my terms better then most other designers. It sets the artisan way. As they created a legend they followed the legends. Thrax Audio elaborate shortly:

"The works of Japanese tube gurus are a source of inspiration for us. Shishido San's designs with transmission triodes manifested trough Wavac Audio and Kondo San's creations at Audio Note Japan are the best examples of the Japanese vacuum tube art currently in production and the different approaches taken to achieve the same goal. Their attention to detail and manufacturing quality inspired us to try and do better. The works and concepts of another Japanese designer came closest to the direction in which we were heading. Never implemented commercially, however, the designs of Sakuma San are a tough example to follow. Directly heated triodes with inductive loads seemed to deliver the effortlessness and tonal richness we are after."


For me there are only two ways to ultra high-end heaven (with one or two exceptions, think Excalibur). Pure A class solid state or best executed tube circuits often or as a rule in A class. Outside of this territory products might sound fine and even above good, but never great in the ultimate sense. It seems that some rules of basic understanding must be followed to achieve state of the art high-end reproduction. And a talent to recognise and implement them.

It is my joy and pleasure to see and hear Thrax Audio venture going totally out of the box and above all trends to create their products in a stunning audible way. This is what true high-end dedication means.


I'm perfectionist by nature and love refined manufacturing combined with the great industry design. Both Dionysos and Heros are an example of what ultra high-end components should look and feel like. From handy remote, that reminds of Mobiado mobile phone to fine artistic details of Dionysos front plate. If you cannot appreciate meticulous CNC work and finish of this preamplifier then you must have other issues rather then respect for finest craftsmanship. I can spot the anomaly in design within seconds. It's just how my inner clocks and aesthetic sensors work. Both gift and curse at the same time as it's hard to get pleased and satisfied. Perhaps it's even peculiar. But, the thing is i can spot the un-perfection from a distance and it irritates me like anything :).

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I love premium feel of things regardless of product type. Thrax products are carrying premium feeling that radiates an instant feeling of proud ownership and substantial luxury. Not in a snob like way, but with a certain aura that clearly reveals the elegancy and profound taste of man behind the company. My urge for things being done right is so rarely addressed with most high end audio products that usually feel rather mediocre in their appearance and design, then something that cost like a car or house.

Dionysos preamplifier and Heros heros monoblocks are wonderful examples of not following the crowd. Not only with their aesthetics, but as you'll find out in next lines also with what matters the most. Sound and music!


I'm an indépendant and without any need to flatter anyone or follow up to advertising money to justify my writing. I can simply write through my passion and freely choose what to test and write about. Mostly I'm after the stand out products that boil my blood. Those who deliver music in its purity and potency. In that search I'm not bound to the price restriction. Both above and below. Thanks God!

Along Kondo Audio Note Japan and Robert Koda so far I simply didn't stumble upon the electronics that could ewoke such an unique musical impact as those two companies can project. Thrax joins them with big pace and it seems that even transcend at few points of Kondo unmistakable delicacy of intoxication.

Even from the first few notes being played through the Thrax Audio Dionysos preamplifier and Heros monoblock combination I was being shot directly into the vein with what Dionysos and Heros could present. A true blissful venom :). The sweet unstrained flow of music presented in a way of Monet and Degas witty view the world. Full of colour vibrancy and feeling of being there. And most importantly with the impact that last and stand continuously. A lot of high-end audio components might impress you at first glance. When you return to the listening, their initial impression fades. Through my listening notes that never happened with Thrax and I'm as excited with the music flow as I was on the first day. That should tell something right!?

With Thrax combo intimacy of sound and musciality hits you at such scale that leaves most of the gear of current high-end market light years behind. Bold statement right!? Here are at workings something that few seems to understand or even write about. Not that I feel egocentric of special, but as I don't have to think in narrow or guided way perhaps this gives me a better position. And I'm used to high-priced high performance gear. I don't get scared or confused easily.

Thrax evoke the energy of motion. The purity of music untouched and so potent in its power to interact with listener without borders or constraints. At stake... It's not only a matter of electronic design being used or implemented, but a subject of art and culture. The fact of the one's view of things general and particular. Choices being made and implemented.

Both Dionysos and Heros give such an impact and it feels so right. How is then that some fail to understand such products. Simple. People get scared of emotional potency and exchange! Over my twenty some years I've seen and heard quite an array of what supposed to be the best of the best. Based on numbers and some reviews those might hold some wicked titles, but at primal role of music reproduction at highest level they most fail to follow up those claims of state of the art. Ultra high-end is not a matter of background listening visionary of most. It's to be experienced directly and non altered. I know live and acoustical music by heart and play few instruments. Being in constant reset of subjectivity keeps me focused and objective. When it comes to the highest judgments I do think its a must to set a certain level of performance. Ultra high-end audio is a science by itself. It takes efforts to create those exceptional devices and it also takes mileages and efforts to understand and recognise them. Like with state of the art food, wine or horology. You cannot become an artisan or distinguish between the mediocre and the best in an easy way. It takes time and dedication on both fronts.


There is something special in the way that few of true state of the art products behaves. It got to do especially with inherited power of music. How it connects with us on the sublime level where things are on the emotional plane and far away from technicality being main reasoning act. It's true, that knowing music scales, history and philosophy helps in appreciating music more. Like with like an art. It adds to experience, but not by default. It enriches you. Once you discover the historical time travel anchors of scales, movements, passions and pains behind the roots of past musical creations the primal impact is even more direct. Perhaps even poignant to a degree based on music material being listen to. But, for true emotional exchange all those variables are not needed, but they're welcomed.

We can argue a whole day long or until the cows go home about how certain audio component do or don't connect us more intimately to the core of performers and their intimate world, yet something do happen with certain audio reproduction devices. What is this exactly we fail to measure and I doubt we ever will, but we can understand a little portion to a certain degree with the overview of the technology being used. Of course when right strikes being taken. Not blindly, and in most cases not straight of the book.

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Our expectations towards ultimate playback should be sky high. As prices. Sharp and direct. In the sense of ultra high end audio we're not buying into luxury segment, but a luxury performance that raises all the bars. I highly enjoy the complexity of any extraordinary design, but if it's only an outhere shell then what's the point. There are to many of such jewellery boxes out there. What I want and hanker for is an extraordinary musical box. Thrax made both wining strikes. With performance and looks. As mentioned above Dionysos looks like no other preamplifier. It's an art form of industrial design being taken seriously and above ordinary. It act as statement in physical appearance and sound performance. In a sense this is a true functional art for the music enjoyment of highest calibre. With Thrax form follow function and vice versus. Quite rare and wicked example :).


Just in time I received Chad Kassem latest version of Getz/Gilberto Girl from Ipanema LP on 45rpm. Now if you need to buy one album per year here is your desert island choice. As with Acustics Sounds Analog Production of Nat King Cole Love Is A Thing analog is as great as ever. Some of the latest analog reissues or contemporary recordings like Norway's 2L digital to vinyl releases brought such a high performance to vinyl, that digital simply watch the burning smoke trail left behind by few miles. If you want to reveal a true potential of any given system then full state of the art analog front end will show the truth. Thrax combination is most enjoyable one brand system I have had pleasure to listen in my demo room. I put a lot of smilies in my listening notes and clearly noted my enjoyment of music and forgetting about the world.

I always do a reality check with the LessLoss set of product. They are my "trade standard" for testing the refinement of things. DFPC power cables quickly show the level of importance of quality cabling on any device. With Dionysos and Heroes the impact was not subtle and it only further showed the true capability of both devices. Analog is my medium of preference for reference performance and this is also where the LessLoss Firewall shows its sublime workings. Combining all this, and with an added Blackbody as Cherry on Top, the neutral performance was made clear. As written in my previous reviews of LessLoss products, they bring balance to performance and show the real potential of any given gear. With both Thrax components and LessLoss in a system they really enter the realm of state-of-the-art replay.


As with Robert Koda Takumi K-10 Thrax Heros pulled the trick of illusion where one loose the objectivity regarding technology being used. In a blind test you cannot figure our if Takumi K-10 is a solid state or tube preamp. It holds all the attributes of tubes, but with the advantages of solid state. I can relate in a same way with Thrax Heros mono blocks. With the delicate power that some tube based power amplifiers might lack, Thrax Heros acted like no solid state or tube amplifier. They actually didn't act as any other power amp I heard. They've gone beyond solid state pure A class sweetens and bring that natural there dimensionality and sense of space from tubes. A daring and puzzling combination, but it worked far beyond of what I expected. Remarkable!

In the upper echelon there are quite few solid state amplifiers that uses a pure class A at their heart core. Take Gryphon, Vitus etc. for example. While they performance brings certain intimacy nothing compare to the purity of Thrax Heros. They don't strain music in any way with dynamic imprint that still take away the "full magic" as with those establisehd pure Class A amps. Heros actually liberate music from solid state "cuffs".

Thrax Audio Heros looks different, perform different and act different. I can imagine only one amplifier being taken to the other shore of things beyond and that's Robert Koda Takumi K-70. I haven't listen to those monoblocks yet, but they're coming for a review in due time.

Heros are not about power but about energy in motion. Its the effortless flow of music that makes Heros so darn warm hearted. You'll get struck by the intimacy and limitless natural nuances when music is being played. Especially with live acoustical recorded music, where one can instantly find and hear the what makes amp performance so elevated.


Thrax Dionysos is a true ultimate component that you build your system around. You can start with it and elaborate when time and funds allow. Its performance goes ming boggling above the given price and fluidity and emotional impact makes you rethink about some of those pricey Japanese products.

If Dionysos resembles the language of Rumen Artarski then all my respect and ego bow down to his efforts. This preamplifier is the labour of respect and love for music and all around approach with premium feeling makes one desire it even more.

You may execute your need for branding, but there is no way to logically and emotionally pass the Thrax Dionysos when you're in the need of system change or in a hunt for state of the art preamplifier. Dionysos redefine the price structure and audiophile money being spend. Even when money not being subjet matter, you'll have the hardest task to find a competitive preamp.

Like with IWC, Patek Philippe, Rolex etc. The feeling of handling things around Dionysos is prestigious and refine in most ergonomic way. Everything makes sense and I simply love the clear, clutter-less front plate without any prints. Anyhow. In few strikes you'll know your way around and enjoy operating it with ease.

In an Apple kind of way there are no visible screws or bolts on chassis. Design like this takes time and dedication. Result is an unmistakable aura which makes Thrax flagship preamplifier unique and stand out from the crowd.

Thrax Dionysos received Mono and Stereo most prestige Uber amp award for preamplier that I though I'll won't gave out anytime soon if at all.


I wrote this review in a bit different way. Above are links connected to the operational manuals and specifications for both products. With Thrax products under review I wanted to share how special and different they are. As products in league comes rarely on market, I felt a need to present them as special and unique.

If any other company would packed so much high priced modular parts and add on all the R & D of Thrax Audio Dionysos would cost a fortune and quickly jumped into the territory of sky high priced preamplifiers like Kondo M1000 etc. You can rant as much as you want with my next statement, but at given price Thrax Dionysos is an actual high-end audio bargain. If we only break down the parts cost and quality of chassis you'll will quickly gave a wake up call for most ultra-high end companies. Money have to come from Rumen Artarski other operations. I highly and openly respect this.

Thrax Dionysos is one of the best if not the best (when implemented in a right system approach) preamplifier currently in production. Yes, quite a bold statement. With almost mind boggling internal architecture that paves the respect to the past and incorporate contemporary solutions Dionysos shifts the paradigms of what is possible when dots are connected in both researched and audible way. This preamplifier now only shows, but screams loudly how many man hours, passion and attention went not only in inner and outer design, but into an actual listening.

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  • Like
Reactions: Stef


Well-Known Member
Feb 12, 2013
Dear Matej,

it is very interesting how different is your review against 6moons.

best regards


Matej Isak

Well-Known Member
Jan 20, 2013
Dear Josef,

indeed. It seems our views and experience of ultra-high end differs by far and thanks God we live in the world of differences :).

I can only repeat what I've written above. Rumen Artarski have one of the most demanding visions in his quest for ultimate music reproduction. Having on hand funds and whatever wanted/needed (full Kondo gear, The Sonus Faber Speakers etc.) he's the man of little compromises. As a successful businessmen and music lover his not the the kind of person to invest a fortune and years of his life in creating an audio dream company and send out half finished products...


Sep 3, 2012
Hi I recently purchased a Robert Kodak k 10... Your review helped get me interested, I got a bit lucky with a demo model nearby, now I've had my k 10 for about 6 weeks and just love it. Very curious to read when u get the Koda amps and how they compare to the thrax and others you've had in house.

Also I'm very curious to try a phono stage on par with the Koda k10... Did u try the thrax phono? I hear Robert might have a phono stage one day soon...really want to hear this....

By the way, great magazine, thanks for doing what u do...

Matej Isak

Well-Known Member
Jan 20, 2013
Hi jfrech,

Very nice purchase. Congrats. You own one of the best preamplifiers in the world. As with above mentioned Thrax Dionysos preamplifier these machines belong to different category. I'm glad, that my review helped and thanks for nice words about Mono & Stereo. It's both passion and hard work combined :).

If everything O.K. Robert Koda Takumi K-70 amplifiers should arrive later this year. I'm as intrigued as you to hear them :).

Yes, Robert is working on the phono preamplifier, but we might wait a bit more to be released. Robert Koda Takumi K-15 preamplifier is coming first as it seems...

I didn't hear Thrax phono yet, but I'll try to arrange for a review as soon as possible. This should for sure be a great partner for Takumi K-10.

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