THRAX Teres Ref 250w hybrid/tube Mono Block amplifiers

TX 08 AM TERES
NZ$ 47,995.00 pr (incl. GST)
Thrax Audio

Unconventional State of the Art Audio components delivering Never Heard Before reproduced Music Performance

New

Teres is based on the architecture of Spartacus. Single ended tube input stage loaded with a phase splitting transformer controlling 2 separate single ended amplifiers out of phase for output. Tube clarity and tone with might and power. Unusual but true..

The C3g tube handles all the voltage gain needed. It uses a new generation or our choke rectified shunt regulated power supply. providing a stable noise free operating point. 

The output stages power JFET cascodes form a bridge that when unbalanced by the input signal via the 2 transformer windings restores balance by adjusting their current conduction trough the load. The 2 output stages actually enclose the load in their control loops and try to correct each others errors reducing the distortion to negligible amounts. Leaving only the “character” of the input stage. 

To reduce the amount of heat generated the amplifier is biased so only the first few watts are in true class A. Music has a crest factor of 10 on average. This means that most of the time we listen with 1/10th of the peak levels. For most users this translates to under 5W. Peaks could reach over 100watts during playback, but only for few milliseconds. For those peaks the amplifier switches to class B using only one leg of the output stage capable to deliver up to 250W/8ohm and 350w/4ohm. 

Not sharing a common reference point apart from the load itself makes the second leg correct for any error produced by the first one. Result is an amplifier capable of extreme power wile delivering exquisite smoothness and low level resolution. 

The driver stage is isolated by the interstage transformer and is not influenced in any way by the output stage maintaining tone colour and resolution at all powers and loads. 

Having the output stages floating around the load prompted for the use of a unique biasing technique powered by solar cells. This was the quietest galvanically isolated power we could come up with. Using opto-electrical conversion we control the bias by adjusting light intensity in the control circuit. 

Teres is an example of modern technology solving age old problems allowing us to go a step beyond.

The physical appearance of Teres is typical Thrax understated elegance. Exquisite finishing ads to the presentation of a solid block of metal like a bigger brother of Heros.

Features

Reviews

Videos

Features

- Tube amplifier architecture with simplest signal path
- Transformer coupling of stages
- Special grade screened power transformer
- Jfet/Mosfet cascode output devices
- Silicon carbide rectifiers
- Microprocessor control
- Audiophile super long life C3g Input tube
- Shunt regulated power supply
- Solar cell bias of Output stage
- Battery bias of Input stage
- Both RCA and XLR inputs
- Compact chassis built like a elegant tank
- 250W/8Ohm 350W/4Ohm
- Zero feedback design
- Finish: Black or Silver anodised aluminium

Reviews

I have not heard any system (regardless its price level) that came even close to Thrax's performance. Bulgarian system delivered extremely rich sound, surrounding me continuously, without and division
Wojciech Pacuła (translation by Marek Dyba)

REVIEW SUMMARY:....sound will be amazingly palpable. It will fulfill expectations of those who search for a rich, clear and close sound rather than presented in a distance. Depth of the sound in outstanding and I am sure that one could credit low-distortion drivers and resonance-resistant (coloration free) cabinets for that. Make and finish is top class. Also elements used for both products are of top quality. Rumen Atarski developed a system he can be proud of.

EXTENDED REVIEW: Thrax Audio - TERES Power amplifier + LYRA loudspeakers
To be honest I can't remember how it started. In my own review of Dionysos preamplifier for January 2011 I wrote that I'd firstly learned about existence of Thrax Audio one year earlier during High End 2010 Show in Munich. But now I really can't remember any details. It seems though that I somehow knew already then that it was a brand worth interest. I was the first, or at least one of the first people who reviewed Rumen Todorov Atarski's product (outside his homeland, Bulgaria). For a few years it was also the only review in Poland, as it took few years to find a proper distributor in our country.

since the foundation of this company its core product has always been a linestage—as if Rumen thought that it was a key element of the system (I always thought exactly the same thing) – that is quite a unique approach in audio world. For the first few years all other products were presented always as prototypes. As you can read below, in fact he started his audio adventure by designing loudspeakers. It took him many years before the first model, Lyra, was finally released in 2014. Just like his preamplifier and power amplifiers also speakers are quite a unique design.

Last month you could read in HighFidelity what a CEO of YG Acoustics, Mr Yoav Geva, had to say about his loudspeakers. Not only do they use many interesting solutions for the drivers and crossovers, but also cabinets of their speakers are quite particular, being a key factor in achieving a final sound. These cabinets are made of aluminium slabs using vibration-free pressurised assembly, creating sort of monolith design, that reminds me of products of another American company – Magico.

Not more then 5-6 years ago using any other material for speakers' cabinets than wood (in one of its forms or the other) was thought to be eccentric (at best), possibly harmless but having nothing to do with "true" audio. These eccentricities included materials like: glass, concrete and aluminium. Today, after the audio world recognised the amazing Crystal Cable speakers (glass) and both above mentioned manufacturers of aluminium speakers, the general view on what is and what is not the "right" material for speaker's cabinet has changed significantly.

Thrax Audio Ltd., a manufacturer of Thrax products, decided to use most rigid, vibration-free enclosures for their products. Based on the experience of other manufacturers, they knew how to do it—it "only" required them to buy crazy expensive CNC machines. So they did. It didn't take long before they had such an advanced machinery and such an experience with using them that some renown European high-end  manufacturers started to commission enclosure production to the Bulgarian company.

A casing of the new power amplifier, Teres, looks like it was carved of solid aluminum block—the fit and finish is that good. Actually it was made of aluminum plates put precisely together, with outer surfaces of side panels  milled in such a way that they look like radiators.

This amp is getting really hot under stress as the current mode uses a pair of single transistors per phase. It is a unique design as there are only two gain stages in a cascode: a single penthode C3g in the input stage and JFET followers in the output. C3g is an octal tube with metal body. Input and output stages are coupled with a single transformer. There is no negative feedback loop.

When it comes to electronics aluminum casings are very common, even such advanced ones as Thrax's. But aluminum cabinets for speakers are still quite rare. Lyra speakers are the newest addition to Thrax portfolio despite the fact, that  Rumen Atarski's first audio project ever was speakers.

It is a two-way, three-driver design, with drivers in D’Appolito array. The concept is quite unique because of extraordinary rigidness of the cabinet, very special, aluminium bass-reflex port design, and very special crossover. The latter sports a huge capacitor for tweeter and that's it! Speakers and amplifiers use a high quality, user-friendly Furutech speaker binding posts.

A few simple words…
RUMEN ATARSKI - Thrax Audio | CEO
The story of Teres.  As you know Spartacus is our statement amplifier, 2 gain stages with Class A push pull output stage. Many people were scared by the exposed tubes and all were requesting a bit more power. So I started working on a circuit that will have a tube controlling a power MOSFET that can replace the output tubes in the Spartacus. Solid state and inductive loads don’t go well tighter and many devices let their gray smoke out. Fortunately for us new devices were introduced to the market that could withstand the high voltages and power required. This gave birth to a unique cascode system for the output. It is still operated at high voltage but not nearly as high as on the tubes. The output transformer used to load this cascode made it sound and behave as a tube amplifier and simplifying the input, as to be essentially a single stage device. So Heros was born.

A year later all our dealers started asking for more power and bigger amplifier with the same character. There was no commercially available output transformer of sufficient quality for power above 200W, so the only option was transformer less output stage. This automatically prevented the use of Heros driving system, so I went back to the drawing board. We resorted to the topology of Spartacus again and implemented it in Teres. we use an input tube for voltage gain and a transformer for phase splitting (same as in Spartacus), but here we replace the standard push pull output with 2 totally independent single ended followers based on a scaled version of our cascode. Running them out of phase to each other and sharing the load, forming a bridge that is unbalanced by the phase splitting transformer signal in order to be re-balanced trough the load with a mirror image of the same signal. The output stage has no character of it’s own, so the sonic color of the the tube stage is the overall character of the amplifier.

Regarding Lyra. The development started around a driver developed by BMS. It uses a ring diaphragm. It was patented more than 15 years ago. During the research for wide bandwidth horns at Spherovox new profiles with different directivity properties where developed. We just adapted one of the designs for high end audio.

It uses a custom "short" version of the driver and the special horn to cover the 1.5k-20k range with an outrageous sensitivity of 112db/W. We use a combination of the horn loading and the High Pass filter to tailor the response of the tweeter while severely attenuating it to mach the mid/bass unites. There is no stress for this driver at ANY level. It practically has lower intermodulation distortion than the amps.!

The 6.5" drivers are used only bellow the 1.5kHz crossover. This prevents them from exiting the breakup modes of the magnesium diaphragms. In order to get the perfect time/phase alignment the front panel of the speaker is carved from solid accommodating for the relative positions of the drivers. Geometry is optimized for listening distance of 3.5m. The solid aluminum prevents any vibrations in the enclosure and specially the front.

THRAX AUDIO in High Fidelity
• TEST: Thrax Audio MAXIMINUS + DIONYSOS + SPARTACUS – D/A Converter + preamplifier + power amplifier
• INTERVIEW: Rumen Atarski | Thrax Audio – CEO, see HERE
• TEST: Thrax Audio DIONYSOS - linestage, see HERE

Recording used for the test (a selection):
• Abraxas, 99, Metal Mind Records MMP CD 0102, CD (1999).
• Abraxas, 99, Metal Mind Records/Art Muza JK2011CD07, gold-CD (1999/2011).
• Aquavoice, Nocturne, Zoharum Release ZOHAR 077-2, CD (2014).
• Bob Dylan, Oh Mercy, Columbia/Sony Music Labels Inc. SICP-30579, Blu-Spec CD2 (1989/2014).
• Helen Merrill, Helen Merrill with Clifford Brown. Singles box, EmArcy/Universal Music LLC (Japan) UCCM-9336/8, "Limited Edition" 3 x SHM-CD (1955/2014).
• J.S. Bach, English Suites 1, 3 & 5, perf. Piotr Anderszewski, Warner Classics/Warner Music Japan WPCS -12882, CD (2014).
• Leonard Cohen, Popular Problems, Sony Music Labels SICP-4329, CD (2014);
• Leszek Kułakowski Ensemble, Looking Ahead, ForTune 0043, "No 031", CD (2014).
• Ludwig van Beethoven, Sonatas op. 109, 110 and 111, piano: Evgeni Korolov, Tacet 208, "The Koroliov Series Vol. XVI", CD (2014).
• Pet Shop Boys, PopArt: Pet Shop Boys – The Hits , Parlophone/Toshiba-EMI TOCP-66252-54, 3 x CCD (2003).
• Porcupine Tree, The Incident, Roadrunner Records/WHD Entertainment IECP-10198, 2 x HiQualityCD (2009).
• Queen, Queen Forever, Virgin/Universal Music LLC (Japan) UICY-15347/8, 2 x SHM-CD (2014).
• Sting, All This Time, A&M Records 212354-2, SP CD (1991).
• Voice Factory, Voice Factory Sings Chopin a Capella, Voice Factory, CD (2014).
• Zapach psiej sierści, soundtrack, music Włodzimierz Nahorny, GAD Records GAD CD 019, "Limited Edition 500 Copies", CD (2014); 

Whatever will I write later, whatever assessment will I pass I would like to send a strong signal already now to all electronic music fans, to those who like close, palpable presentation, and to those who expect not a huge space far behind speakers, but a close sphere built around listener sitting in its center: all of you can can search no further. If you can afford this system just buy it and keep it for ever.
It is a system of a very strong sonic character. What it offered might not have been exactly my cup of tea, but it did not matter at all. This time I didn't mind at all to fall for something offering quite different qualities from those I usually search for. The quality of the above mentioned sound features is so high that this Thrax system could be exhibited in the Museum of Sound as a perfect example of a high class, sophisticated piece of art.

Lyra speakers together with Teres amplifiers build a warm, rich sound that is also amazingly vibrant. This is obvious no matter what recording one plays, no matter what music genre. The precision this system forms the sound with, makes you wonder about choices of other  audio designers, in particular those who create loudspeakers. If you use Thrax amps with most of speakers using paper drivers you will realize that they tend  to mask problems generated by other elements of the system. Lyra show us that paper, which under certain circumstances sounds warm and soft, is used to mask a roughness, harshness of the sound.

I think that these solid, metal cabinets of Lyra speakers work in similar way. If one uses a low distortion, precise drivers in such z high class cabinets they will start to act as sort of magnifying glass providing listener with information about any problems originating from any element of the system. To use that to one's advantage one needs a very well designed crossover and a high class system driving these speakers.

Not all manufacturers utilizing paper or plastic cone drivers for their loudspeakers with wooden cabinets do that because they can't do any better. Anybody who knows JBL, Spendor or Harbeth speakers can vouch for that – these "antique" technologies and materials, properly used, deliver outstanding results. But more often then not using them will result in less favorable sonic results.

Thrax chose a different, I think most difficult way. There are only very few companies that took the same path and succeeded—YG Acoustics and Magico are best examples. Thrax system produces similar results. Anybody who claims that transistors produce a "cold" sound, and metal cabinets and drivers deliver a "dry" sound, has really no knowledge of the audio industry and audio products. If he based his opinion on particular products, these particular products must have been faulty and not the technology or solutions. The latter offer particular benefits, have some flaws of their own, but are surely not a bad choice—only a particular application might be wrong.

Was it because of elimination of cabinets resonances, or usage of amazingly linear C3g tube, (whose cousin,  C3m, I knew from some other top products), or most likely due to many elements working together, these speakers create a dense sphere made of air, sounds, details that surrounds listener. If only recording we play allows that. Because when we play a recording that was made in such a way, that we perceive sound as coming from far behind speakers, than Thrax allows the sound out of this sphere. That's how the latest Piotr  Anderszewski CD recorded in Warsaw with J.S. Bach's English suites 1, 3&5 from Warner Classics, sounds like. I have a version of this recording released in Japan. This type of production focuses on a soloist presented quite close to the listener, but it does not create a "wow" effect as there are not so many other sounds coming from sides or from behind us. It is not a very lively sound. Thrax system did not try to "light the presentation up", didn't try to deliver the very essence of the music, it simply conveyed the recording in a way it had been made proving why other recordings, like Anderszewski from Carnegie Hall sounded better.

Quite a different result we shall achieve with recordings where some spatial spatial effect were used, were out of phase sounds were used to create an impression of sound coming even from behind listener. These recordings create an impression of surround—multi-channel sound. There are quite a lot of such recordings. The best ones were prepared using the Q-Sound system, like, for example: Roger Waters' Amused to Deathor Sting's Soul Cages.

There are also some Polish interesting recordings of that kind. I really like the group Abraxas so I often listen to their album 99. They are representatives of so called art-rock (progressive rock), and this particular album was recorded in 1999 by Jacek Gawłowski, who received a Grammy Award in 2014 for Włodek Pawlik's Night in Calisia. For that album he was involved as a producer and a mastering engineer. He was also involved in a project of re-issue of first four Czesław Niemen's albums.

Anyway, on 99 between tunes there are additional pieces of music that include very special spatial effects. The reviewed system recreated those spatial effects in an amazing way. I have not heard any system (regardless its price level) that came even close to Thrax's performance. Bulgarian system delivered extremely rich sound, surrounding me continuously, without and division for front and back sounds.

This system will present in a very interesting way also some recordings that are usually not "liked" by most audio systems. I mean those recorded with microphones placed very closely to instruments, mixed from multiple tracks, usually as multi-mono—this actually means 99% of music material that's been produced for many years now. For example—the latest Leonard Cohen's album, Popular Problems. System delivers the foreground very close to the listener. It is a large scale, rich sound so it creates an impression that we sit in the first row, just in front of the stage. This manner of presentation was even clearer when I listened to Voice Factory album with  Chopin's music, sang (a Capella) by NOVI Singers (album comes from GAD Records). Microphones were placed so closely to singers that it created an impression of a very small distance between listener and singers standing in my room. The reviewed system provided also information about quite aw realization, not so perfect voiced were taken by microphones placed very closely.

Tonal balance is set quite low. Speakers deliver very clear, rich sound, with bass going really, really deep. The lowest octave is "indicated" mostly with higher harmonics, but these are delivered in almost perfect way which creates an impression that we listen to much larger speakers and the we can really hear even lowest notes.

Treble seems warm but also very vibrant. Cymbals sound seems bit darker than in reality, even slightly darker than delivered by my Harbeth speakers. But there is no "rounding" or "softening" of leading edge. It's a rare combination—sound are not "lightened up", and yet the decay phase is rich and long enough.

The key element of this presentation is midrange though. Many good things can be said about deep bass and rich treble, but they both seem to only complement midrange that is amazingly rich and complete. Images are not precisely depicted as they are presented very close to the listener. Their energy is extraordinary though. Sound is quite energetic despite the fact it is also quite warm.

This particular set of features should satisfy all fans of music I mentioned before, plus fans of electronic music. I believe that if Tadeusz Łuczejko, whom I met a few days earlier (a musician, member of Aquavoice, an organizer of Gorlice Ambient festival could have listened to his album Nocturne on Thrax system, who would have loved it. The sound was very essential, rich, mature but also very pure.

Summary

I have defined a potential owner of this system at the very beginning of this text. Thrax does not like compressed  signal, as it decreases scale of the sound, and creates an impression of the whole sound coming from area in axis in front of the listener. It does happen even with well produced recordings like Porcupine Tree's  The Incident. The whole structure of the music seems to fall apart, there is chaos instead. Thrax doesn't forgive that. Classic recordings with a lot of air BEHIND performers (and above them) tend to be re-interpreted as the foreground will be shown closer to us and there will be less of the air in a distance. Also phantom images won't have a real depth.

But if one listens to the music I mentioned before sound will be amazingly palpable. It will fulfill expectations of those who search for a rich, clear and close sound rather than presented in a distance. Depth of the sound in outstanding and I am sure that one could credit low-distortion drivers and resonance-resistant (coloration free) cabinets for that. Make and finish is top class. Also elements used for both products are of top quality. Rumen Atarski developed a system he can be proud of.

DESIGN

TERES
Teres is a monaural power amplifier. It is a hybrid design, with C3g pentode (in triode mode) in the input stage and transistors in the output stage. According to Rumen Atarski there are only two (!) gain stages. What's more, input stage (tubes) are loaded with transformer—it is the large cube in the middle of the casing. Behind it there is only a second cascode gain stage based on JFETs and MOSFETs.

Developing a device based on such a simple concept requires a lot of time and effort. At least if sound quality and good measurable parameters is what we want to achieve. Teres is uniquely simply design. Input section is placed on a PCB bolted to the back panel of the device. It includes almost complete power supply section for C3g. Power transistors are placed inside two small aluminum boxes. These have a shape of a section of cylinder. They are bolted to the sides of the device and they produce most of the heat one can easily feel after turning Teres on.

In the middle there is a large toroidal transformer and two large smoothing capacitors. On top of them designer put a small board with SiC Shottky diodes. This material called carborundum is used in many top designs, one of them being SPEC Corporation Designer Audio REQ-S1 EX phonostage.

Amplifier sports RCA and XLR inputs, but the device works in an unbalanced mode. Signal is balanced in coupling transformer. The whole circuit is controlled by a microprocessor that sits on separate board and sports a separate power supply. Teres works without negative feedback.

LYRA
Lyra is a two-way, three-driver monitor. It sports a vented enclosure that is made of aluminum plates screwed together. Also bass-reflex port is made of aluminum. A mineral wool was used for internal damping.

Drivers are screwed to the front baffle from inside, so the screws are not visible. A solid aluminium carved front panel incorporates a horn with specific directivity and frequency response. Its shape was developed by a company Spherovox. A ring diaphragm compression driver was custom built by German company BMS.

Two mid-lowrange magnesium diaphragm 6.5'' woofers work together. These look like top line SEAS drivers. They sport a magnesium membrane and copper phase plugs. They work below 1,5 kHz.

Loudspeaker sport a puristic crossover of  the 1st order, built of the most expensive elements including Mundorf silver capacitors and a huge coil. Even speaker posts were chosen to achieve the best sound quality—these are the same posts that are used in amplifier—Furutech FT-816.

The only thing these speakers miss are matching stands. For now any solid 70cm stands should be fine, but since these are high-end speakers they will show any problem with accompanying system including low quality stands.

My New Reference amplifier...
Key Kim

REVIEW SUMMARY: Listening to orchestral music once again presented the amplifier’s innate ability to paint a realistic three-dimensional picture of the live event. The Teres recreated a soundstage with floor-to-ceiling, wall-to-wall spaciousness that was seamless while never once oversized. It rendered large-scale symphonic works as well as the Karan with a seemingly limitless dynamic contrast along with a powerful and full bodied low-end. Dvorak’sNew World Symphony No.9 in E Minor, Op.95, with Fritz Reiner conducing the Chicago Symphony Orchestra (JVCXR-024), produced enormous size, scale, and, more importantly, realistic dynamic swings. Whenever I cranked up the volume, the Teres kept its composure under whatever sonic onslaught that came down the cables.

the Teres hybrid mono amplifier brings so much to the table that, relative to other reference amplifiers in today’s market, it’s a bargain. They produced magic with every listen including a new reference of quiet, speed, and transparency. Timbre rightness coupled with color density and warmth is what ultimately won me over. Hats off to Rumen Artaski for creating a new benchmark so close to his superb sounding Spartacus, with lower voltage and no exposed tubes and can be used with mainstream loudspeakers. The Teres has earned my Stereotimes 2015 “Most Wanted Components’ award. Highly recommended!

EXTENDED REVIEW: I’ve reviewed Thrax Audio equipment over the years and found it to be what I qualify as the cat’s meow. In fact, I admired its craftsmanship and musical prowess so much that I chose the Dionysos as my new reference preamplifier over my Karan Acoustics preamp that had been my workhorse for nearly a decade. Rumen Artarski, founder and chief designer of Thrax Audio stated in many discussions I've had with him that “Thrax Audio components are highly addictive and once exposed to Thrax you are not the same anymore”. I was warned. Now I’ve got the Thrax bug. And that ain't good!

Thrax Audio’s latest product, the Teres Hybrid mono amplifier, is the subject of this review. Artarski told me about two years ago that he wanted to design an amplifier to sound as close as possible to his superb sounding Spartacus, with much lower voltage and no exposed tubes, to be used with more mainstream loudspeakers. Unfortunately, it is impossible to totally replicate the sonic signature of the Directly Heated Triodes and transformers used in the Spartacus. The Spartacus was designed primarily to drive efficient loudspeakers with maximum refinement. Keeping the sonic signature and specific presentation of Thrax gear in check, the Teres was created. Teres is an innovative design that still follows the “less is more” approach. Interestingly, Teres uses two separate and discrete output amplifiers completely independent of each other. Each consists of a single JFET/MOSFET and bias logic devices that were derived from computer and motor drive applications. Artarski is open minded and loves to think outside of the box. 

To make the Teres perform as intended, Artarski resorted to a new type of shunt regulator circuit for the input stage and a radically new bias method for the output stage. Artarski utilizes battery bias in the input stage to provide the cleanest signal path for the ultimate C3g tube (a minimum lifespan of 10,000 hours!) that drives the phase splitting transformer. Solar cells are used to bias the output modules; any other implementation would have required some electrical connection between the output stages, but with the solar cells they are totally independent. Cleverly, silicon carbide diodes are used which have no reverse recovery. They make for cleaner switching (and are gaining momentum in audio). Two output stages feature very high input impedance and do not affect the sound character of the transformer loaded input stage. The Teres uses zero negative feedback in any form; the load has no connection with the input stage and cannot affect it. This gives stability of tonal color and a low level resolution. Teres uses interstage transformers to create two identical out of phase signals that feed the two output stages. The Teres output impedance was reduced and the output stage is now DC coupled to the speaker in order to handle the huge currents needed by inefficient loudspeakers. Lastly, the input stage is totally isolated and optimized for all the voltage gain defining the sonic character. Teres can output up to 250 Watts per side into 8 Ohms without a shift in sonic signature and keep all the low level “space” information at the same time. Teres incorporates a new type of shunt regulator circuit for the input stage and a radically new bias method for the output stage, utilizing, as I noted, clever solar cells to generate the floating bias voltage.

The Teres mono amps arrived in sturdy wooden crates with thoughtful carrying handles. First class all the way. Just as I remembered when reviewing the Spartacus and the Dionysos. Artarski is a perfectionist; every little details counts from the components he chooses to the final details in shipping as well. He wants to make sure everything is flawless. I concur. Removing the screws opens the wooden crates to reveal how professionally the amplifier was packed. Thrax’s build quality is impeccable and the Teres mono amps are exquisitely crafted; fit and finish is top notch. The chassis is stunningly finished in solid aircraft aluminum plates and the chassis looks as if it were carved out of solid aluminum blocks. Brilliantly, the outer surface of the chassis works as a heat sink. Indeed, the Teres never got above warm to the touch, even when listening to symphonic music at realistic levels. The Teres is manufactured using Thrax’s ultra state of the art CNC machinery. Cleverly, it has a stand-by switch, which doesn’t need to be turned off after each listening; it remains on stand-by. With my Karan a solid-state amp, I was able to leave it on 24/7. But with the Teres it gets even better; I could put the amps on standby, which turns off the tube and leave the circuits on. This way it sounds really good from the moment you start playing the next time. In fifteen minutes you are playing at the components full potential! On the back of the Teres there are both XLR inputs and RCA inputs and it is equipped with gorgeously crafted Furutech speaker binding posts and IEC. 

Artarski told me that the Teres had been through 72 hours burn-in time in the factory to ensure sound quality and workmanship. However, he recommended 150 hours of burn-in time to fully settle it in after its arrival. I started listening right after a quick setup and right out of the box, I knew this was going to be something very special. As I logged on more hours the Teres started to gain more bloom and harmonic beauty. I’ve been looking to upgrade my Karan with a new reference and lately I’ve reviewed many great sounding reference amplifiers like the Concert Fidelity ZL-120V2SE, Reimyo KAT-777, and Franck Tchang's ASI Grand Stereo. These are superb sounding reference amplifiers; especially the ASI, and they bettered my Karan in every possible way. But for some reason I didn’t pull the trigger; I wanted a little more tube magic in my new reference amplifier. My readers by now know that I’m not the type who jumps ship to the “flavor of the month.” My reference Karan amplifier served me well as it did everything just right, was built like a tank and was - most importantly - trouble free for nearly 10 years.

My reference system has evolved and improved, thanks to Rumen Artarski from Thrax Audio. I’m really loving my new Thrax Dionysos preamplifier which of-course has a symbiotic relationship with its brother in the Teres mono amps. Cables are the unbelievable sounding Enklein David cables throughout the system (review on the way). Also (lucky me), near the end of my Teres review, I received Thrax Lyra speakers which were quite a surprise both in terms of their arrival and performance.   

Music to my ears

Normally I would let a component burn-in for about a month or so and then I would start to listen discreetly. Not with the Teres. My enjoyment started immediately but only got better as I put in more hours. The Teres possesses a very quiet and super transparent footprint and produced a mesmerizing three-dimensionality stage. So much in fact, the Teres sounded as though I moved my speakers further away. I didn’t hear any tubbiness but rather its performance was more graceful, gentle, and at ease. Images were more solid in a holographic space and were more liquid. The Teres’s solid-state output revealed itself more acutely, particularly on the bottom, where excess bloom gave way to greater dynamics, grip and speed. The amps had immediacy and were rhythmically alive producing a punchier, more direct life-like sound; yet in no way was the sound clinical, harsh or harmonically depleted in any frequency. This all resulted a seamless, top-to-bottom wall of sound by way of my Consensus Audio Engineering Conspiracy loudspeakers (and Thrax Lyra loudspeakers: which by the way produced a taut bottom-to-top transient response and an excellent overall speed without sounding etched or analytical).

One listening session I was in the mood for a female vocalist. I put on my new reference vocalist, Melody Gardot’s “The Rain” from MY One and Only Thrill CD (Verve). I was introduced to her beautiful voice at last year’s Munich show in the Silbatone Acoustics room. They played a tract, on her CD entitle “Your heart is as black as Night”, and it was a thrilling experience. Silbatone Acoustics tube electronics from Korea showcased Melody's astonishing voice through a majestic sized set of Westin Electric 1936 theater loudspeakers. Melody Gardot’s performance was beautifully rendered to the point that I was almost fooled she was in the room. As soon as I got back to the States, I ordered the album and since then it’s been added to my reference recordings. I put on “Baby I’m A Fool” and the music flowed exquisitely by the Teres mono amps not quite to the level heard by those Westin Electric, but still quite impressive. Vocal and instrumental timbres proved spot on, thanks to the Teres robust, full-bodied midrange. The Teres mono amps gave the music more life, the ability to deliver pace, while maintaining its natural character. As much as I love my Karan, the Teres mono amps performed better. The Teres reminded me of the Spartacus which I reviewed (here). Melody's vocals startled me – first by the immediacy and solidity of the image –  then by the improved complexity of her phrasings. Her sensual voice possessed a more tangibility, textures and tonality. Everything that I have come to expect from a Rumen Artarski design. Then some.  In the end, the Tere's presentation of this remarkable recording proved to be tonally, dynamically, and rhythmically more captivating than anything I've reviewed thus far. Quite a soul-stirring affair and what this hobby of musical appreciation is all about.  

The Teres boasts and uncanny solid footing in both worlds: it has the right amount of tube glow and solid-state control and speed. The best solid-state amps generally produce greater transient speed and clarity, better dynamic contrast, and superior bass extension and control. Predominantly, solid-state designs deliver levels of transparency that few tube designs can accomplish. However, compared to the best tube designs, even the best solid-state amps can produce an overhyped transient attack not generally associated with live music and it can sound harmonically flat. And often, solid-state’s superior transparency is accompanied with an analytical and crunchy sonic aftertaste, with the leading edges a bit unnatural. Tube amps, on the other hand, are generally harmonically overripe and sound richer than life; they are slower and softer than life on transient notes, but they lack solid-state’s control on the bottom.

I put on a familiar recording of Bill Evans’ Alice In Wonderland (JVCXR-0051-2) and the sound can be best described as liquid and beguiling. The Teres revealed a blacker background and an ability to paint vivid tonal colors. Paul Motian’s shimmering cymbal work came alive with incredible sheen and naturalness that was neither tube soft nor solid-state hard. Scott LaFaro’s double bass sounded as striking as I’ve ever heard on this recording. This legendary trio were natural and yet their attack never drew attention. The sustaining of their notes and their resonance decays were reproduced with an uncanny naturalness. Timbres are richly portrayed, with a density of color and warmth that makes even the best solid-state sound ever-so-slightly more mechanical. The Teres resolved tremendous amounts of detail without ever sounding overwhelmed, etched or analytical. The Teres has a remarkable ability and a realism that conveys a vividly convincing illusion of live instruments.

Listening to orchestral music once again presented the amplifier’s innate ability to paint a realistic three-dimensional picture of the live event. The Teres recreated a soundstage with floor-to-ceiling, wall-to-wall spaciousness that was seamless while never once oversized. It rendered large-scale symphonic works as well as the Karan with a seemingly limitless dynamic contrast along with a powerful and full bodied low-end. Dvorak’sNew World Symphony No.9 in E Minor, Op.95, with Fritz Reiner conducing the Chicago Symphony Orchestra (JVCXR-024), produced enormous size, scale, and, more importantly, realistic dynamic swings. Whenever I cranked up the volume, the Teres kept its composure under whatever sonic onslaught that came down the cables.

Conclusion

Rumen Artaski was right, the Thrax Audio is addictive and I need HELP because I am hooked. Yep, I pulled the trigger and purchased this review sample. Ladies and gentlemen, it’s that good a product. At $30k, It’s not inexpensive but the Teres hybrid mono amplifier brings so much to the table that, relative to other reference amplifiers in today’s market, it’s a bargain. They produced magic with every listen including a new reference of quiet, speed, and transparency. Timbre rightness coupled with color density and warmth is what ultimately won me over. Hats off to Rumen Artaski for creating a new benchmark so close to his superb sounding Spartacus, with lower voltage and no exposed tubes and can be used with mainstream loudspeakers. The Teres has earned my Stereotimes 2015 “Most Wanted Components’ award. Highly recommended!
...... Key Kym.

Jason's Adventures Continue on Day 2 at MHES 2016
Jason Victor Serinus 

Ah yes. Through the audio jungle I thrashed, through sound both thrilling and threadbare, until, having totally exhausted the alliteration resources of my thoroughly thumbed thesaurus, I alighted upon the thoroughfare of Thrax. Once there, I threw all literary pretence aside, and thrillingly cried, "Thanks be to Thrax!"

And with this borderline hysterical paragraph behind me, I solemnly pledge to never again abandon critical impartiality in order to indulge in the mad plunge into holographic hyperbole!

Over it I may be. But what I'm not over is how good this room, assembled by HiFi Imports, sounded. Perhaps in part due to canny speaker positioning, the Thrax Lira 77lb. loudspeakers threw an astoundingly large soundstage that was far larger than any two-way stand mount of this size has any right to create. The presentation had lots of atmosphere, with a beautiful midrange. Equally important, the system could perfectly spotlight instrumental solos in a most musical manner. (Note: When I first encountered these speakers in Newport Beach last June, they were not broken in. The set-up sounded considerably better this time around.)

First up, on LP, were the very space music "Intro" and "Numb" tracks from Sam Brookes' Kairos. Everything sounded just as it should, which means perfectly musical and all-enveloping. I had never heard the music before, but it sounded so fine that it felt like just what the artist hoped we would hear.

Then came "St. James Infirmary," with cymbals and horns sounding drop-dead gorgeous. And I wasn't the only one who marveled. Two dealers who had chosen to sit RMAF out this time around were seated behind me, enjoying the music just as much as I did.

Playing while I was present, in addition to the loudspeakers: Thrax Dionysos linestage preamplifier, Thrax Orpheus phono preamplifier with LCR RIAA equaliser, Thrax Teres Hybrid power amplifier, Dohmann Helix 1 turntable with new Schroder CB tonearm.

Leaving with regret: yours truly, Jason Victor Serinus 

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Thrax electronics and loudspeakers, world premiere The Döhmann turntable, Munich