After an extended radio silence of several years, the Kora company started to re-emit a strong and clear signal since last year thanks to its new range of integrated amplifiers animated by a new circuit. The surprise was as unexpected as it was beautiful when it reappeared in 2018 by announcing the birth of a new concept of hybrid amplification around a scheme where the tubes were implemented in a modern way within ‘an owner floor called Square Tube.
After an extended radio silence of several years, the Kora company started to re-emit a strong and clear signal since last year thanks to its new range of integrated amplifiers animated by a new circuit. The surprise was as unexpected as it was beautiful when it reappeared in 2018 by announcing the birth of a new concept of hybrid amplification around a scheme where the tubes were implemented in a modern way within ‘an owner floor called Square Tube. Developed by Bruno Vander Elst, director of the company Kora High Fidelity, the Square Tube circuit is actually an operational tube amplifier whose technical name is Vacuum Tube DC Operational Amplifier for op tube amplifier that passes direct current. But where can the square come from ? The final prototype implemented to validate the concept arranged the four tubes of the floor in square, the idea was thus retained for the final name of the floor.
EXPLANATIONS The four tubes we are talking about are famous double triodes of the ECC family, specifically ECC82 and ECC83, polarized in pure class A with, therefore, an operating point placed in the middle of the load line. This operating point is imposed by current source on the two ECC83 triodes input into the differential stage and by reference voltage for the two ECC82 triodes output in order to guarantee a maximum service life. The heating of these tubes is regulated, direct current and referenced to earth for ECC82, but alternating and floating for ECC82. They compose a voltage amplification stage whose dynamic gain is extremely high on the one hand, and whose output attacks a push-pull stage with additional Motorola original power transistors polarized in class AB on the other hand. This output stage thus works as a follower, without gain and at very low impedance, which guarantees very high operating stability, even on complex loads. It somehow replaces the output transformer of a fully tube amplifier without the usual technical drawbacks such as problems of phase shift in the bass and treble, poor coupling in the bass and current limitations. Let’s sum up. The Square Tube provides the amplification and control functions of the audio signal, the output transistors adapt the current demand to the speakers, they «transform» current what the tubes amplify in voltage. In the case of the TB140, the youngest in the catalog made up of two other more powerful models TB200 and TB400, the four tubes of the Square Tube assembly are supplied between two seriously regulated and stabilized voltage rails, a positive of +280 V and a negative of -180 V, i.e. a total high voltage value of 460 V. The voltage at the output of the Square Tube is therefore a balanced voltage, or alternating with respect to the audio ground, which defines the final power of the amplifier after conversion into current through the transistor power follower. A portion of the total voltage of 460 V is used to obtain the nominal power of the integrated unit, which will never work under stress.
WITHIN TB140 The chassis of the TB140, like that of its two big brothers, is entirely made of aluminum plates covered with a matt and glitter paint in an anthracite gray tone. The front face adorned with the brand logo receives an acrylic plate on three-quarters of its upper part. On the right, a flush dial allows pressing and rotating to navigate in the menu of the TB140, it is assisted by a display with yellow LED diodes which materializes the programming in the menu and more generally the current operating state of the device (connected source and volume level in particular). For example, you can use the menu to adjust the balance between channels or adjust the sensitivity of each input in order to maintain the same sound level when switching from one source to another. The TB140 is supplied as standard with a remote control which takes over the current functions. The transistors of each channel are placed on a finned heatsink glued to the rear panel. A 300VA toroidal power supply transformer placed in the front center provides the voltages necessary to create the internal 460 V, two 10VA auxiliary transformers supply power for the timed heating of the tubes. The Square Tube is located on the vast circuit at the bottom right. Two other smaller cards, one on the back of the wheel and one at the bottom of the chassis, manage the display, the wheel controls and the source selection, the control signals pass through a ribbon cable.
THE SET UP We used the Kora TB140 indifferently on our three usual pairs of speakers, the T&T Nel Ultime, the ZU Soul and the Diptyque DP 77. Although these three models have radically different requirements, the Kora has been able to satisfy them every time. We can therefore validate its versatility, in terms of coupling with the different speakers. Regarding the wiring, we stayed on relatively simple models. According to the designer, exotic references are not his strong point. We have nevertheless noted that a good power cord brings a more obvious to the performance of this device.
THE SOUND How to describe what is indescribable? This is indeed the difficulty that we faced when listening to the music reproduced by this integrated amplifier Kora TB 140. Quite often, electronic devices dedicated to sound reproduction have a paw, a personality, a kind of identity with which we recognizes them, and who characterizes them. Of course, the eclectic music lover with intensive consumption will rather seek a product which banishes colorings and which tends towards neutrality. Fortunately, there are neutral products. A priori therefore, this Kora is to be classified in this last category. To tell you the truth, we spent a lot of time listening to it, before trying to analyze its performance. Because performance is a question here. Indeed, the TB 140 gave us a very nice demonstration of musicality. We have tried many different messages and styles with him. From symphonic to rap, from techno to new wave, everything goes admirably, provided of course that the disc has been produced correctly.
What can we say about its intrinsic performance? The bandwidth is wide, but not the widest we have heard. On the other hand, what characterizes the spectrum reproduced by the Kora is an absolutely remarkable consistency for the price. From the deepest bass to the widest treble, there is no break in the timing. We find this wideband type signature that characterizes the most musical products. This device knows how to demonstrate homogeneity. During listening, we therefore have the sensation of tasting an incredibly coherent message. A bit like a concert. As a second point, we will emphasize the lack of grain that this amplifier demonstrates. Whether on a large symphonic band, or on a small jazz trio, only the substantial sonic essence is transmitted to us, and none of the slag that could pollute it. This feeling, that of purity, is just as exhilarating as the first. The two combined allow us to access the musical message more directly. With the Kora TB140 we are undeniably closer to recorded music. Finally, we had an immense pleasure in feeling the way in which this amplifier is capable of reproducing the sound stage. With him, sound never lives in the listening room in the same way. Each disc has its panorama, its structure, and its space. Your living room thus takes on different proportions depending on what you are listening to. From minimalist it becomes majestic, from intimate it becomes spectacular. The Kora TB140 is thus able to fade completely before the intention of the sound engineer to recreate exactly what the musicians wanted to transmit to us. In this sense and at this price, it is a performance that should be saluted very low, because it is rare.
OUR CONCLUSION We had a real crush on this device, and all the more marked, that we salute here a French achievement. We know that we have brave engineers and innovative designers in our country, but when they venture this far in the quest for sonic pleasure, we must greet it with vigor. The resurrection of the Kora brand has begun successfully. The youngest of the new range has completely convinced us and I can not hide the fact that we are eager to listen to the rest of the siblings. Bravo, 1000 bravo to its designers.
TECHNICAL SHEET
PRICE €4.900 DIMENSIONS 420 x 100 x 340 mm WEIGHT 9.5 kg NOMINAL POWER 2 x 70 W at 8 ohms, 2 x 100 W at 4 ohms FREQUENCY RESPONSE 20 Hz – 20,000 Hz @ +/- 1 dB SENSITIVITY 1 V (line input), 4 mV (MM phono input) ANALOG INPUTS 4 RCA line (15 Kohms), 1 RCA phono MM (47 Kohms) ANALOG OUTPUT 1 RCA (2 Kohms, after adjusting the volume) OUTPUTS 2 pairs of HP plugs
You know the drill. In the past, it was a beautiful novel, it was a beautiful story, a story that began under the impetus of André Calmettes. Since its creation, the small company in Villedubert has not changed its habits. Everything is designed, validated and built in situ. Always present and more active than ever on the international high-fidelity scene, the French manufacturer has been pursuing its quest for the Graal sonore since the company was founded in 1983. For thirty-five years, the tube assemblies of this top-of-the-range French pillar have invariably been able to outperform the perpetual technological innovation of global competition.
One of the many secrets of the musicality of Jadis electronics lies in the quality of the oversized output transformers, whose windings are cast in resin, which guarantees total waterproofing and high thermal stability. Take a look at the JA80 MKII blocks on this test bench and you will begin to understand the spirit of the house.
PREAMPLIFIER JP80 MC The Jadis badgées 80 electronics are undoubtedly the brand’s best known. The JA80 MC preamplifier is divided into two chassis, one containing the power supply circuits and the other the preamplification stages. They are installed in superb polished stainless steel frames with front panels lined with a polished solid brass plate. The RCA-only connectors are of high quality. The electronic components of the audio section are mainly wired in the air with the assistance of small printed circuits. The power supply section «dispatches» its discrete low-voltage regulation components on a large epoxy glass printed circuit board and its high-voltage regulation stage with EL84 and EF86 pentodes is partially wired in the air.
The origins of this separate power supply deserve some explanation. The original creators sought a total freedom from current problems by isolating the audio stages from the facets of the sector. The main transformer supplies an amplifier of about 100 watts whose mission is to amplify a sinusoidal signal from a generator. This signal supplies a second transformer whose secondary transformer is connected to a rectifier bridge and creates the high voltage that is then filtered. There are three cascade controls, the first provides a reference signal, the second creates a high voltage of absolute stability regardless of the mains voltage, and the third regulates the high voltage. Line level amplification is provided by two double triodes ECC83, the CD input has apparently been given special attention with an ECC83 in cathodic mounting for optimal impedance matching with the source. The RIAA phono section consists of three ECC83 double triodes with an ECC88 two-tube circuit for preamplification of voice coil cells. It is in this part of the device now called MK II that some improvements have been made to reduce noise because the phono stage with very high gain (see «the numbers») was likely to hang in HF. Rather than inserting a scale, the volume adjusts separately on each channel from resistance switches. Passive components have been selected or even manufactured according to specifications, as is the case with some decoupling, connection and RIAA correction capacitors.
AMPLIFIER JA80 MKII This mono block is capable of delivering 90 W in pure class A and even in low frequencies. This gives an overview of the quality of the output transformer. The JA80 is the first amplifier of the Jadis brand, which appeared in 1983. It is now available in MkII version providing compatibility with the new KT150 power pentodes in the shape of a rugby ball. Even before trying to lift it, the imposing size of the two transformers, power supply and output, suggests the very high weight of the block, which also takes up little floor space. The chassis is in the Jadis standard. On the stainless steel front panel with brass lining, two switches and an LED diode that changes from red when the power is turned on to green after a few minutes of preheating. The hull and bottom are made of non-magnetic stainless steel and act as shielding. The hull supports the transformers, six high-voltage filter capacitors, the two largest at the rear for the output stage, and six tubes. The input tube is a double triode ECC83/12AX7 and the driver phase shifter is assigned to an ECC82/12AU7.
The four KT150s are configured as double push-pull triple distributed load, class A polarization is automatic and the cathode circuit is protected by an individual fuse. A godsend when it will be necessary to replace the previously matched tubes because no adjustment will be necessary. The JA80 MKII can work with other types of pentodes, KT120, KT90, KT88, 6550, 6CA7 or EL34. Please note that changing to another type of power tube requires a small internal modification of the device. If that is your intention, here is our advice: do not hesitate to talk to your dealer who will give you the right advice. The output impedance can be internally modified from 1 to 16 ohms by a set of strips that configure the secondary windings of the lifetime guaranteed output transformer. It will therefore be necessary to open the device to switch from 4 to 8 ohms for example. The power supply unit is oversized for better heat and vibration dissipation. The heating of the filaments is done by alternating current with balancing and noise reduction. The gold-plated solid metal loudspeaker plugs are specific to Jadis and allow bi-wiring, and the gold-plated connector system ensures the faithful transmission of signals.
THE SET UP We had the chance to taste this quartet of tube electronics already well established and impeccably installed in the Audio Video Feel showroom ; let us thank him warmly for it! If possible, the preamp and its power supply should be placed close to the various sources, and each block should be left on the ground not far from the loudspeakers. Even in asymmetric mode, modulation links are not critical for the Villedubert builder. The JA80s are able to power a large number of loudspeakers without any contraindications.
THE SOUND I had the chance to listen to my first Jadis already 30 years ago, and it’s a moment I haven’t forgotten! Since then, the whole range has passed between my ears, up to this latest version of the mythical JA80. In a few seconds, everything comes back! Rarely has a brand been able to embody the beauty and dazzling beauty of sound to such an extent. There is a signature «Jadis», it is absolutely undeniable, and it has been able to survive the years, intact and pure… With this «80» ensemble, the music acquires a unique dimension of its kind, it inhabits the sound space like no other device. The sound of Jadis is grandiose, oversized, exceptional in the true sense of the word, but never caricatural. There is the sound «Jadis», and there are the others, whether we think in terms of tubes or not. In any condition, a Jadis is extremely pleasant to listen to because it offers an exacerbated vision of the sound space, so as to transport the listener into a dimension that he is not only not used to being in contact with, but that he does not even suspect a priori the existence of. Listening to your first Jadis is an initiatory journey that never leaves you indifferent, especially since the addiction imposed by these devices is not based on the usual criteria for assessing a hi-fi link, but rather on a totally non-standard seduction power, based, it is true, on aptitudes that are also non-standard, and which for the moment coincide with objective and proprietary technical criteria. A Jadis really sings! And that’s why it destabilizes us. With our four «80’s», we spent hours listening to many purely acoustic records that caused us great emotions.
If we have to stick to classical criteria of appreciation, we would say that the Jadis are imperial in the fundamentals of the medium and dynamics. 90% of recorded music is based on this median register that the «80» reproduce with not the most scrupulous accuracy, but diabolical magic, and a consummate art of elegance and distinction. The ancients know how to make music as beautiful as possible. The sound remains round, fleshy, with a lot of substance, very beautiful textures. And above all, they know how to create an atmosphere whatever the level of listening! On a jazz trio, it’s divine. On a string quartet, it’s magical. On a large orchestra, and as long as the associated material is up to the task, it is phenomenal. The «80» know how to deploy the medium in its most intimate inflections, without any hardness, without the slightest artificial trace. The degree of homogeneity is staggering. And since the dynamic behaviour is imperial, all this passes like a letter to the post office. It should also be noted that, as with the delicious Ayon Crossfire III, the subjective power is much higher than the figures announced. And yes, it’s one of the priceless virtues of big tubes!
OUR CONCLUSION Built to perfection to be beautiful but also to last for decades, Jadis electronics are built to stand the test of time and offer the most exciting vision of recorded music possible. Thirty years after its creation, the brand still carries this standard high! Witness, these four «80» which constitute one of the most beautiful tube amplification sets with separate elements that a music lover can dream of owning. Power, presence, openness, emotion and emotional intensity, that’s what this quartet is all about, which will always be relevant in 30 years’ time. In the past, a sure bet and a lifetime investment!
TECHNICAL SHEET JP80 MC
PRICE €19.300 DIMENSIONS 430 x 175 x 345 mm (each frame) WEIGHT 30 kg (total weight) FREQUENCY RESPONSE 20 Hz – 50.000 Hz (line inputs) GAIN AT 1 kHz 57 dB (MM phono), 84 dB (MC phono) INPUTS 1 RCA phono MM, 1 RCA phono MC, 1 RCA monitoring OUTPUTS 1 RCA «main out», 1 RCA recording
TECHNICAL SHEET JA80 MKII
PRICE €17.000 DIMENSIONS 260 x 240 x 240 x 625 mm WEIGHT 35 kg RATED POWER 90 W SENSITIVITY 500 mV FREQUENCY RESPONSE 20 Hz – 27.000 Hz
Cable is a strange field where the best sometimes comes into contact with it, to say the least… Yet no serious audiophile would consider today not wiring his system properly from the source. And it doesn’t matter if computer scientists scratch their heads and look at us with their black eyes when we say that a cable through which digital data flows has a significant influence on sound quality. Surprising, isn’t it?
An essential link in any digital source operating on the basis of files stored on a hard disk, the USB link has been tested by a large number of cable manufacturers, with results ranging from poor to excellent. Much closer to this second option, we were able to test the Celesta, Eterna, Aura and Lumina models from the French manufacturer Esprit.
THE PRESENTATIONS Richard Cesari, who has been at the head of Esprit for 22 years, is a French manufacturer of high-fidelity, high-music cables. He is one of those craftsmen to whom we give our credit, first of all for the quality of their work, but also for their constancy in experimentation. Like many other national creators, Esprit perpetuates a kind of know-how of French cable. Its very wide range makes it possible to reach the «first-time access» music lover as well as the experienced audiophile capable of going very far in the material (and financial) investment of his system. Whatever the cable, the manufacturer provides little technical information on the structure and composition of its cables. On the other hand, we know that the most important thing is a drastic choice of properly sorted components.
For example, on the entry-level Celesta USB, pure long crystal copper strands were used in symmetrical assembly, isolated from noise by integral shielding and protected by a high-voltage dielectric. The rather sophisticated insulation work includes a quadruple air protection. The connection system is qualitative and the cord is covered with a nylon braid. A silkscreen print is applied to the two heat-shrinkable tubing tubes. This cable, assembled manually, is guaranteed for life. As for the Eterna USB, its structure includes pure copper strands preserved by a complex assembly, first an asymmetrical dielectric, then a double progressive shielding on air with integral optical coverage, and finally a multiple insulation on air. The Eterna USB cable is therefore larger but still loses its flexibility. Manual assembly takes several hours per cord… This cable is also completely assembled by hand and guaranteed for life.
The Aura USB model is approaching the summits. The symmetrical configuration of the data conductors ensures high immunity to electrical noise. There is an asymmetrical configuration of the dielectric, but the shielding is both partial to ensure that the data bus is isolated from the power supply bus and integral for total protection of the entire structure, is achieved by double screen. As for the Lumina USB, the manufacturer’s best USB cable except for the limited edition Lumina Signature, it combines all the technologies previously used in a more extensive formulation and implementation.
THE SET UP We use the USB connection at the output of an Apple laptop, network drive, or server. On the other hand, to obtain the best results, we avoid entering directly into the USB converter. We prefer to use a USB interface, in this case a 32-bit/192 kHz Matrix X-SPDIF that allows us to attack converters in AES/EBU when possible, or S/PDIF on RCA. In this way, the jitter level at the DAC input is drastically reduced. The four Esprit cords were placed in the same place at each stage of the comparison, after an identical running-in period of about fifty hours, according to the manufacturer’s recommendations.
THE SOUND First in the running, the Celesta, offers a beautifully crafted sound result. It should be noted that just under 400 €, this is already a cordon of a certain price from which we expect a quality service. And we are not disappointed, thanks to a wide sound spectrum, and especially a lack of stress, hardness, a beautiful opening and a silky and delicate palette of tones. At its price, nothing to say, the Celesta already gives a lot, in a fluid and delicate style, with a well channelled energy. The transition to Eterna does not revolutionize the sound personality of this line. This is a Celesta whose roughness would have been erased, the ends of the spectrum extended, and the dynamics released. Objectively, the passage from Celesta to Eterna gave us the impression that the speakers were bigger, that the sound was increasing in size and sitting. The gains are clear and going back is very difficult. With the Aura, we clearly change category. We go from a very nice supercharged 4 cylinder to a six cylinder in line, noble in its simplicity. The sound acquires a higher class of evidence and refinement.
The bandwidth does not seem dispropor-tionately higher. On the other hand, the listening is much wider, richer. Each recording is now characterized by an even better designed personality. The specificities of sound recording emerge much better. The listener’s sensory perceptions are more solicited. In short, «we are there», and in a very tangible way. At this point, we even wonder why go higher. It is the passage to Lumina that offers us the answer to this question. With it, you gain two cylinders to benefit from even better breathing. So much air, and what sensations. Here everything is only calm, luxury and voluptuousness. The seat is sovereign, the bass majestic, the medium extremely natural, and the treble totally free and absolutely free of artificial tonic. The price is high, but the performance is there. It’s one of the very best USB cables we’ve ever had the opportunity to listen to.
OUR CONCLUSION These 4 cords are very well made and deserve your full attention. What we can tell you is that it is essential to choose with the help of your reseller the one that will best match your system. So, on an excellent converter whose USB input is not at the same level as the S/PDIF or AES/EBU input, which happens regularly, we were able to get better results with the Aura than with the Lumina. With the Aura, the sound was completely balanced and musical. With Lumina, the higher resolution power and the better dynamic capacity highlighted the deficiencies of the link, and made the result dull. And when we inserted the Matrix X-SPDIF interface, it was the Lumina that worked better, simply because its environment allowed it to express itself fully. It is therefore important to take these criteria into account to make the best choice between these four excellent cords.
TECHNICAL SHEET
PRICE IN 1 M. € 390 (Celesta) € 790 (Eterna) € 1.480 (Aura) € 2.600 (Lumina)
In late 2018, Devialet is revisiting its Expert range with new updates and the long-awaited addition of the excellent Core Infinity circuit, which boosts the performance and possibilities of its devices. We have chosen the smallest of the Expert, which is already a successful device.
Not only does the Expert 140 Pro incorporate all Devialet technologies, but they have been further improved to the point of becoming new. No less than 107 patents protect these purebred French innovations.
REVOLUTIONARY ACRONYMS If the Devialet box set is a marvel, its bowels are just as impressive. The sumptuously arranged interior is a reference in terms of layout, order and logic. Splendid! It includes the new switched-mode power supply, better decoupled from the mains, faster on transient calls and now developing 4000 W at peak, as well as ADH, SAM, DAC, AIR, RAM and EVO… Uh, what ? How ? How ? All these acronyms are in reality the spirit, the soul, the essence and the existence of a Devialet. These few letters summarize the many technologies developed by the manufacturer. ADH Intelligence is a hybrid amplification method where analog Class A amplification known for its sound refinement and powerful and compact Class D amplification operate in parallel. SAM or Speaker Active Matching adapts the sound signal precisely and in real time to the characteristics of SAM Ready speakers (speakers for which Devialet has created a correction algorithm that can be downloaded by the configurator).
The DAC also known as Magic Wire is the digital to analog converter that is only 5 cm away from the speaker outputs. AIR for Asynchronous Intelligent Route is a 24/192 compatible high definition streaming system that can be used in Ethernet or Wi-Fi. The RAM for Record Active Matching is an MM/MC phono preamplifier that can be fully configured by the configurator, particularly in terms of load, resistive and capacitive, and the equalisation curve chosen among 13 available curves. Finally, the EVO for EVOlution is the integrated electronic platform entirely controlled by an evolutive software, it allows the regular updating of the electronics. The 140 Pro also benefits from the new Core Infinity card. As its name suggests, this new intelligent core includes the Devialet OS operating system. Based on a Linux kernel, this OS has been perfectly adapted for performance-based audio uses. Extremely evolutive, Core Infinity is also built to stand the test of time. For this reason, the computing power of this card has been greatly oversized. But judge for yourself: it first includes a quad-core ARM processor running at 1 GHz supported by 1 GB of DDR3 RAM memory and 4 GB of Flash memory.
Core Infinity also features the most robust network architecture ever built on Expert Pro, providing stability that is perfectly suited to streaming music in high definition via a Gigabit Ethernet port and a 2.4 GHz/ 5 GHz Wi-Fi module. This module is equipped with an internal antenna to cover most situations, but also with a removable external antenna to add gain or to remote any other external antenna equipped with an SMA connector. Finally, a 500 Mbps HomePlug AV2 PLC module allows networking via the Expert power cable.
Core Infinity finally embeds a number of hardware and software improvements. First of all, we notice an additional audio DSP, in addition to the one already existing on the motherboard, which will provide an additional power reserve to support future software evolutions. The FPGA circuit has been improved to provide more power to the Devialet OS, ensuring optimized audio signal routing and a new distribution of clocks minimizing jitter. This results in a significant gain in audio quality. The USB interface has been improved to support new audio formats in the future. We note the presence of 3 ASRC (Asyn-chronous Sample Rate Converter) in order to anticipate future developments of Expert and in particular compatibility with additional sources. Currently only 1 ASRC is used. Finally, R & D has integrated a time and date conservation system via a PSTN battery for an ultra-fast start of network services. It’s very simple, but you had to think about it!
THE SET UP Like any connected product worthy of the name, the Devialet Expert 140 Pro requires proper implementation. But, in all honesty, we must admit that the installation protocol developed by Devialet has the merit of simplicity and flexibility. Indeed, the user does not need to act on the machine directly. Instead, he goes to the manufacturer’s site in the configuration tab, after having registered his machine online, of course, and he proceeds step by step to the different settings. Phono, network, digital inputs, SAM if necessary, everything goes through it. The configuration thus determined is saved and then copied to an SD card provided by Devialet. All you have to do is insert the card into the appropriate slot on the back of the device, and, miraculously, your fully customized device starts working according to your wishes. For our part, we made all our listening in UPnP from our server, and with our Linn Sondek LP12 turntable. It should also be noted that unlike the vast majority of machine builders at this price, Devialet has the good taste to offer its customers a good quality power cord, in this case an Audioquest NRG X, a model sold for more than 100 € public price. It’s a delicate attention. Finally, as with any high-end machine, care should be taken to place the Devialet Expert 140 Pro on a stable and rigid support.
THE SOUND As time goes by, and with each new generation, the Devialet sound gains in fluidity and delicacy. If the Frenchman has always known how to master the ardour, precision and power, today he brings them a very pleasant touch of naturalness, immediately perceptible, from the most accessible model in the range. The Expert 140 Pro offers a sound reproduction whose rhythmic follow-up and dynamic mastery are still as impressive as ever, but which is expressed with more modeling and softness. The tonal balance is very good. It promotes the intelligibility of the message, transparency and naturalness. Devialet is in favour of removing all kinds of discolouration, and this can be heard very clearly. We played a large number of HiRes files, and we felt very clearly that we were as close as possible to the original signal. However, this magnificent transparency is not expressed at all at the expense of life and the way music materializes. The dynamic behaviour of the Expert 140 Pro remains a model of its kind, with a speed of reaction that often makes it perfect. On a large orchestral mass, the tutti manifest themselves without the slightest settling, and with sovereign intelligibility. The same goes for a drum solo, or powerful layers of superimposed bass. The piston work of the woofers is ensured by a flow of watts controlled to the millimetre and of extraordinary vigour. Listening to loud electronic music on large speakers with the Expert 140 Pro is an absolutely exhilarating experience. But this device is not limited to that, it excels on small formations where its sharp sense of analysis hits the mark every time. Debussy’s trio was sifted through with magnificent acuity and a splendid sense of proportion. Far from being sectarian, the Expert 140 Pro is at the service of all the music it reproduces with a mineral and luminous essence, textures of infinite variety, and a lot of sitting.
OUR CONCLUSION Thanks, among other things, to Core Infinity, and its extensive functionalities, Devialet has taken a decisive step forward, which allows it to make its electronics even more relevant and efficient. It is surprising to see to what extent the French manufacturer has succeeded in applying the great virtues of its ultimate products in its entry-level range. That’s why, in our opinion, the Expert 140 Pro, positioned just below the 5.000 € mark, is a formidable and efficient machine, with unparalleled flexibility at its price, and capable of delivering great musical thrills on a very large sample of speakers.
TECHNICAL SHEET
PRICE € 4.990 DIMENSIONS 383 x 383 x 40 mm WEIGHT 5.65 kg OUTPUT POWER 2 x 140 W RMS / 6Ω SIGNAL TO NOISE RATIO 130 dB OUTPUT IMPEDANCE 0.001 Ω BANDWIDTH BANDWIDTH DC-30 kHz @ -0.1 dB DC-95 kHz @ -3 dB MEMORY MEMORY 1 GB of DDR3-RAM 4 GB Flash CONNECTIVITY Wi-Fi 2.4 GHz / 5 GHz 802.11ac, compatible with 802.11a / b / g / n Ethernet RJ45 100/1000 Mbps USB Audio 2.0 Asynchronous ANALOG INPUTS 2 RCA line and 2 RCA phono MM/MC (depending on configuration) ANALOG OUTPUTS 2 pairs of HP plugs DIGITAL INPUTS 1 USB-B, 1 Toslink, 1 S/PDIF mini-jack 3.5 mm, 2 RCA S/PDIF (depending on configuration)
THE GENESIS OF DEVIALET The year 2018 marks the eighth anniversary of the launch of the D-Premier amplifier, Devialet’s very first production. The buzz caused at the time was considerable! Indeed, the device entirely created and developed by this newcomer to the world of high fidelity is unlike any other known electronics. This sleek and ultra-flat UFO in mirror polished solid aluminum houses a preamplifier, amplifier, DAC, streamer and phono stage, inputs configurable by an Internet configurator, all linked by a proprietary scheme protected by numerous patents. The profession is not accustomed to this kind of tidal wave, either technical or aesthetic. The arrival of such a machine shakes up the design of high-end audio electronics as we have imagined it since the beginning of Hi-Fi. Despite conversations and criticisms that are going on in professional clans, customer feedback is almost unanimous. Breathtaking aesthetics and WAF at the top level, outstanding user-friendliness, especially with this dream remote control and the scalability of the product, undeniable musical qualities. Devialet’s innovative concept hits the mark by providing a modern response in line with the demand of 21st century music lovers who want to listen to music in a simple and qualitative way. A source, a pair of speakers and a minimum set of cables are all that is required to put the D-Premier into service.
THE PHILOSOPHY BEHIND THE TECHNOLOGY The name Devialet refers to Guillaume Vialet. This Diderot’s companion participated in the writing of articles in the Encyclopedia in the 18th century, a major work that was the first French encyclopedia. The considerable work it represents makes it a symbol of the work of the Enlightenment, a philosophical movement against oppression of all kinds and for the progress of the world. Devialet’s instigators are deeply inspired by this intellectual approach, the company is a true engineering company at the service of progress in sound science. The D-Premier has served as a springboard for the company, which has since expanded its proposal with the introduction of Phantom connected speakers and has continuously improved the performance of its amplifiers in the Expert range since May 2013. The latest Expert Pro range would not exist without the level of expertise achieved with the Original Workshop Limited Edition launched in 2015. As for the 1000 Pro, it is the most powerful and advanced of all the electronics created to date by Devialet.
The GT Series loudspeaker range reflects the desire of Thierry Comte, the one-man orchestra of Welcohm Technology based in Pin in Haute-Saône, to push back the barriers of domestic sound reproduction as far as possible.
The designer’s creativity is embodied in the latest CAD tools and then tested dynamic simulations on computers and analyzers using the FFT finite element method. The prototypes are then screened for vibration measurements by laser interferometry before the essential step of validation by the subjective evaluation of listening, merciless and indispensable arbiter. All the components and technical solutions that take place on board the top-of-the-range GT3-HD column are exclusive to the brand and form an indivisible whole, as are those of the other models in the series.
The GT3-HD column is at the top of the GT range, which includes the sparkling GT1-HD, one of the most sparkling compact speakers currently available on the world market, and the GT2-HD column, a kind of GT1 with a more muscular bass. From a technical and technological point of view, the three speakers share the same roots, the same spirit, the same DNA. However, the GT3-HD takes a more royal, sovereign approach with specific loudspeakers and very high specifications. There is a real consistency of range within this series imagined by the manufacturer, each superior model being directly derived from the previous one in an indisputably more sophisticated and therefore more efficient version. If we can consider the GT2-HD as a GT1-HD that would have been grafted with a subwoofer, the GT3-HD can be seen as a GT2-HD whose every component has been perfect, has been optimized, has been the subject of even less compromise.
GT3-HD VOLUMES The GT3-HD is a three-way column and four speakers, each bass, midrange and treble register being distinctly assigned to two 18 cm boomers, a 15 cm midrange driver and a 28 mm dome tweeter respectively. The agreement remains bass reflex and takes into account the fact that the two woofers that equip the loudspeaker play together in two thirds of the overall volume of the cabinetry made of MDF with lamination of 3 mm plates for the curve of the side walls. As with the GT2-HD, the tuning vent opens under the speaker, which rests on a decoupled base. Internal reinforcements placed near and between the midrange bass transducers stiffen the structure under good sound pressure. The midrange transducer plays alone in its own closed room, so it is acoustically isolated from both boomers. It is mounted in a cavity called PRD for Progressive Rear Damping, filled with damping material and whose cone-shaped rear surface gradually compresses the wave that is then damped. It is converted into heat and can no longer return to the membrane, which results in a very smooth and precise sound, especially on the transients.
A REAL BUSINESS CARD The GT3-HD is the brand’s technological showcase. The speakers are from the Absolute Series. The bass is therefore reproduced by a pair of LD180s that operate up to 250 Hz. The diaphragm of this bass driver is lightened by eight holes around the core cover in order to decompress the copper-ringed core as much as possible and to cool the 35 mm diameter and 22 mm high copper coil wound on a Kapton and Nomex support. The enormous ferrite of 12 cm in diameter contributes greatly to the excellent sensitivity of these two units. The medium is provided by an MLD150, which covers the range from 250 to 2500 Hz, the specific alloy diaphragm is mounted on a special profile LDS suspension that pushes the progressive arrival of the first fractionation beyond the useful operating range. A solid aluminium anti-vortex warhead improves directivity and helps to cool the magnetic motor and the 25 mm diameter copper coil simultaneously. In addition, the spider and suspension have a generally constant and symmetrical stiffness coefficient so as to ensure equidistant elongations with respect to the rest position and to impart a restoring force proportional to the movements in both directions. The 100 mm ferrite FWI (Force Without Inductance) magnetic circuit extends the notion of symmetry by creating a symmetrical field around the rest point of the 25 mm diameter copper coil in the 6 mm long air gap of the MLD150s. The inductive influence of the coil has been reduced by the installation of a copper ring on the specific geometry core. As for the SD28 ND04 RD tweeter, «the» GT tweeter, it operates above 2500 Hz and the 28 mm treated silk dome climbs to 30000 Hz. The neodymium ring magnet unlocks the sensitivity measured originally at 98 dB. The CCAW coil, for Copper Clad Aluminium Wire, is mounted on an aluminium support. It is shorter than the air gap to ensure constant flow even on large displacements. The very high flow in the ferrofluid submerged air gap releases the dynamic capabilities of this loudspeaker. As with the MLD150, a copper ring core reduces inductance and linearizes the response curve while reducing intermodulation distortion. The profiled and granular front face of the tweeter is made of die-cast aluminium according to an ADP (Anamorphic Dispersion Pattern) profile which ensures excellent off-axis dispersion.
ATOHM PERFECTION To guarantee the best temporal alignment of the loudspeakers, to ensure that the phase of their emissive centre is properly respected, a specific TCC filtering for Time Coherent Crossover or temporal coherence filter meets this need, it integrates a time calibration cell, in practice an electronic delay line, on the acute channel. This cell allows the use of a first-order cut-off slope to limit phase rotations at the connection frequency. Various correction cells for various physical phenomena inherent in a loudspeaker system are also inserted. The GT3-HD has two three-position switches -2 dB, 0 and +3 dB to adjust the frequency response of the midrange registers, between 500 and 2500 Hz, and treble registers from 2500 Hz, for a total of 9 possible combinations. The internal damping of the cabinetwork uses cotton felt and Dacron. However, given the «tube» appearance of this tall column, the problem of the reflection of the first resonance waves between the walls of the column enclosure much higher than wide and deep remained to be solved. As with the GT2-HD, the GT3-HD was added a laminar absorption cavity in the top of the enclosure by throttling the section behind the medium volume. This acoustic transformer ends with a volume filled with damping material perfectly dosed behind the tweeter. The principle called SWD for Standing Wave Damper, channels the back wave which is then damped, the first resonances are then cancelled. At the bottom of the enclosure, another cavity has been built on the height of the cylindrical vent, which can receive a few litres of sand if necessary, which will reinforce the stability of the enclosure on the ground. The GT3-HD’s base consists of two bases, the underside of the GT3-HD and the base itself, which introduce a progressive decoupling called PDS for Progressive Damped Spiking. Through two sets of cones, one between the column and the base, the other between the base and the ground, and spacers between the enclosure and the base under stress from the weight of the enclosure, residual vibration energy is absorbed by the massive underside of the column.
THE SET UP We had the opportunity to listen to the GT3-HDs, among others, in a rather spacious room of about fifty square meters, and we were struck by the ease with which these speakers know how to appropriate the space. We thank New Tone and Jean-Michel André for this demonstration. These beautiful columns were combined with an integrated Micromega M-One amplifier, with which they got along very well. GT3-HDs are not difficult to power, but their potential argues for qualitative as well as quantitative amplification! In terms of placement, we would advise you to keep a respectable distance from the corners of the room. Indeed, the energy deployed by GT3-HDs can be quite high, and the radiation induced at this point will be detrimental to the readability of the message. With respect to the rear wall, the problem is less difficult because the decompression vent radiates towards the ground. But still observe a good thirty centimetres.
0, 30° directivity curves. Absence of marked directivity, low and perfectly regular attenuation, will result in a great stability of the stereo image and a good focusing of the soloists.
Impedance versus frequency curve. Curve of a particular system of 3 channels + 1 bass reflex. The filtering, in soft slope, integrates a module of temporary shimming on the treble allowing to compensate for the p&ysical offset of the motor coils (TTCTM technology). The cabinetwork physically provides an impedance adapter and acoustic filter (SWDTM Technology).
Curve per third of an octave in the axis. Representation of the three settings Smooth / Linear / High Definition. The attenuation is constant and perfectly regular, proof of the extreme rigour in the filtering design.
Waterfall curves. Extremely fast damping. This is partly the result of the combination of SWD and PRD technology, which respectively treats the standing wave at the top of the cabinet and provides progressive damping of the medium independently. Reflection of a true know-how.
THE SOUND For the first few minutes of listening, we were satisfied with chaining the tracks and enjoying the music without trying to analyze it. Indeed, the GT3-HDs have given us a playful, joyful and truly rewarding performance, especially since the eclectic music lover will be able to alternate large and small ensembles, baroque and techno, jazz and pop. GT3-HDs are not sectarian. On the other hand, they have their own way of embracing you in their universe. In the latter, the recorded music is reproduced on a large scale, with wide basses that extend in width and depth without attenuation. These columns are not stunted, but they are not barred by 38 centimetres either.
And yet, they know how to deliver a very well behaved bass, which ventures particularly low, with a lot of information. High frequencies are also a celebration, with an elegant signature that combines when modulation demands it. The voices are thus crunched frankly, with a beautiful light and all the required precision. They are solid reference points to validate the degree of naturalness towards which a speaker is capable of reaching. The same applies to acoustic instruments with which it is difficult to cheat, as well as to any reference point that is easily identifiable in reality. Here, we admire the neutrality of the GT3-HDs associated with a kind of listening comfort that is never denied, even when the sound becomes thick, even on particularly complex formations. Finally, one of the most attractive features of GT3-HDs is their ability to put recorded music into perspective. We will not hide from you that we attended a demonstration where their position placed them very advanced in a vast room, and that they made us enjoy an absolutely exceptional sound scene. Certainly the work of phasing was masterfully concluded by their designer. By closing our eyes, we were simply unable to locate the speakers in the room. On the other hand, we were able to witness the meticulous reproduction of a vast, coherent and phenomenally accurate three-dimensional image.
OUR CONCLUSION We had an undeniable pleasure living for a while with the GT3-HDs. They are chameleon speakers endowed with an innate sense of melodic coherence and capable of imposing a powerful rhythmic connivance with their owners. They are speakers with which we experience music more than we observe it. In addition, their ability to play (very) loudly without giving any sign of weakness is a plus that will win the opinion of music lovers who appreciate living music. This is further proof (but was it necessary?) that the French are able to design and manufacture speakers worthy of comparison with the finest in world production.
TECHNICAL SHEET
PRICE € 7.980 DIMENSIONS 240 x 1190 x 435 mm WEIGHT 37.5 kg FREQUENCY RESPONSE 35 Hz to 30.000 Hz RATED IMPEDANCE 6 ohms POWER HANDLING Up to 300 W RMS (800 W peak, less than 400 ms) SENSITIVITY 92 dB/2.83 V/m
