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Marja & Henk
Financial Interests: click here
Sources: PS Audio PWT; PS Audio PWD; 2 x Thorens TD160; Thorens TD124; Dr. Feickert Blackbird/Zu DL-103;
Streaming sources: Foobar2000; XXHighEnd
Preamp/integrated/power: Tri TRV EQ3SE phonostage; PS Audio Trio P-200;  Audio Note Meishu with WE 300B (or AVVT, JJ, KR Audio 300B output tubes); Yarland FV 34 CIIISA; Trends Audio TA-10; WLM Duo Amp; NuForce Icon Mobile; RSA Predator; Qables iQube V1; Devialet D-Premier [in for review]
Speakers: Avantgarde Acoustic Duo Omega; WLM Gran Viola Monitor Signature + Duo sub; Podium Sound Podium1; Arcadian Audio Pnoe [in for review]
Cables: complete loom of ASI LiveLine cables; full loom of Crystal Cable cables; Audio Note AN/Vx interconnects; Audio Note AN-L; Siltech Paris interconnects; Gizmo silver interconnect; Nanotec Golden Strada #79 nano 3; Nanotec Golden Strada #79; Nanotec Golden Strada #201
Power line conditioning: Omtec Power Controllers; PS Audio Powerplant Premier; PS Audio Humbuster III;
Equipment racks: Solid Tech Radius amp racks; ASI amplifier and TT shelf
Sundry accessories: Boston Audio Design Mat and Tuneblocks; Furutech DeMag; Nanotec Nespa #1; Exact Audio Copy software; Dell server and laptop w/Windows Server 2008, Vista and XP; iPod; wood, brass, ceramic and aluminum cones and pyramids; Manley Skipjack
Room treatment: Acoustic System International resonators, sugar cubes, diffusers
Room size: ca. 14.50 x 7.50m with a ceiling height of 3.50m, brick walls, wooden flooring.
Price of review item: €12.000 incl. VAT

The following tells the story of our initial encounter with the Devialet D-Premier - about when it stayed at our place the first time and why it returned again. Cryptic? It was. For us. Read on to learn what happened and how we gained fundamental new insights.

It all started when we were asked to attend a presentation on the new Devialet D-Premier. Dutch distributor D&D Audio arranged the presentation on board of the SS Rotterdam which is moored permanently in Rotterdam's port. The combination of allegedly stunning amplifier and a visit to our former stomping grounds was tempting enough to undertake the 90-minute drive. Boarding the SS Rotterdam tipped the scale completely. To appreciate it you must know that the Rotterdam steamer used to be the flagship of the Holland America Line. It started as a liner between Rotterdam and New York and later became a major cruise ship. After a major overhaul that restored its former architectural beauty inside and out it now found a final resting place. Read more on the wonderful Parsons steam engine and click on Engineering and Design.

So, we were to encounter 21st century digital design and 19th century boating glory. The presentation was given by one of Devialet’s designers, Mathias Moronvalle. Devialet is a young company that was started by Pierre-Emmanuel Calmel, a telecommunications engineer at telecom giant Nortel’s French operational branch. As a serious melomane he fantasized about the ideal amplifier which would also be the most efficient. The combination of best and efficient led to the basic idea of cross-breeding a class A amplifier with a class D amplifier. How was the big question. On this quest Pierre-Emmanuel was soon joined by Mathias Moronvalle who then also worked for Nortel. Both took the risk of quitting their steady jobs and dove head first into some very heavy R&D.

That was 2004. A year later the technical design was ready and patented in France as a Class AD audio amplifier in which a class A amplifier generates the voltage and a parallel class D amplifier injects current such that the loudspeaker sees both amps. In 2006 the adventure started in earnest when Pierre-Emmanuel pronounced the proof of concept ready and the two pioneers met designer Emmanuel Nardin who brought along Quentin Sannié and later Manuel de la Fuente. Together these gents launched Devialet. Private investors willing to back a new company and finance the—in hindsight lengthy—process from concept to  production stepped in as well. By the end of 2010 Devialet headquartered in Paris was ready to produce the final D-Premier in a Normandy facility and unleash it on an unsuspecting market.

Mathias Moronvalle - Manuel de la Fuente - Hennie Dolleman (D&D)

In his presentation Mathias stressed first and foremost that the D-Premier is neither a ‘digital’ amplifier nor class D. It is an ADH class amplifier, a true hybrid of class A/D. This he meant for all attendees to understand. The looks of the D-Premier are utterly unique but not just styled to look sexy. Just as with the components beneath the shiny armor, there is more to it which we’ll get to. In the room were two D-Premier amplifiers. One without the bottom cover was mounted on a stand to shamelessly display its innards. One of D&D’s dealers had brought in a pair of Avalon Indra speakers together with a Spectral CD transport so those were connected to the properly sealed D-Premier.

Within the D-Premier One one can distinguish eight different sections and all contain something that is either radically or ‘just’ different from any other design. Looking at the denuded machine a strong resemblance to a high-quality computer becomes evident. Think of an Apple iMac or blade server rather than PC, add high-tech parts and eliminate all OEM. The motherboard completely fills up the highly polished aluminum cover. When looked at with the socketry facing the observer, there is a distinctive power supply module at top left followed to the right by a bank of coils creating the power supply’s choke filter. Top right are six large capacitors for energy storage. Just above the IEC connector bottom left there’s the AC filter, at its right the two class A amplifiers. Above these Devialet placed the D/A converters. Slightly covering these amps and converters sits the separate class D amplifier unit and finally at bottom right sits the input processor as part of the motherboard. All these sections are managed by a central processor unit.

Let’s dive into these sections a bit closer starting with the power supply. Inside the 4cm high enclosure there was very little room for a conventional linear power supply. Instead of adding an external power supply the design team went a completely different route. They figured out how to build an extreme flat power supply based on switch-mode technology. In high-end audio circles an SMPS is often a no-no probably because few have done one properly. Devialet found a way to let the power supply take a continuous flow of current from the mains. A conventional SMPS takes energy only from the peak of the AC sine wave. This introduces harmonic distortion generated by current spikes at 100 or 120Hz depending on 50/60Hz AC frequency from the wall outlet. These harmonics happen in the crucial audio band.

Inside Devialet’s power supply module capable of delivering 600 watts the French use in-house designed planar transformers. These ultra-thin transformers are not built up with wire coiled around a core but consist of 16-layer stacks of printed circuits. As Pierre-Emmanuel’s dream was to build his amplifier as efficiently as possible, the D-Premier’s power supply also includes power factor correction. In an ideal world the power factor should be 1 to signify 100% efficiency. In the real world extra power is consumed to do the necessary work. This becomes wasted energy. With a PFC composed of a bank of capacitors this is compensated and Devialet’s power supply operates more efficiently

The stored energy in the capacitor bank is shared between both positive and negative rails. When the positive rail requires current, instead of loading down the negative rail its current is injected into the positive rail. A total of 13.200μF filter capacitance is available. A microprocessor controls the power supply and as we’ll see later on, this controller can be programmed to alter the power supply’s behavior. In total roughly 50% of the D-Premier’s motherboard are dedicated to the power supply from AC filtration to energy storage.