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Devialet D-Premier Upgrade to Expert 250 Pro

12-11-2020 | By Arnis Balgalvis | Issue 112

The Devialet D-Premier is sure to go down in audio history as a game changer. When it was introduced in 2010, little did we know that the D-Premier would alter the integrated amplifier landscape forever by redefining the concept of what an integrated amplifier is.

Up to that point, an integrated amplifier had consisted of a phono preamp, a line stage, and a power amplifier. With the D-Premier, Devialet added a DAC to that line-up. This move turned out to be of such significance that it permanently changed the concept of what an integrated amplifier represented. 

But that was not all. At the same time, Devialet used the D-Premier to introduce a completely new power amplifier technology named Analog Digital Hybrid, or ADH for short. It was Pierre Calmel, one of the founders of Devialet, who conceived the idea of taking an exceptionally linear Class A amplifier and combining it with a highly efficient Class D stage. The Class A amp provides a very clean analog voltage at the speaker, and the powerful Class D stage takes care of the current demands of the load. ADH technology was revolutionary and is only available in Devialet products.

And the D-Premier took the audio industry by storm. It was widely recognized for its superb sound the world over by universally positive reviews and enthusiastic listeners.

During the past decade Devialet has grown into a significant High End powerhouse. Their current product offerings consist of a very diverse integrated amplifier line-up as well as several powered loudspeakers featuring innovative technology. Devialet's amplification products are headlined by the Expert 250 Pro integrated amplifier.


Bear with me for a moment, while I backtrack. 

It was ten years ago that my audio mindset was seriously rattled. After reading a review of the D-Premier by Paul Miller in the April, 2010 issue of Hi Fi News and Record Review, I was never the same. (Arnis has reviewed the unit in PF as well, that review can be found HERE)

I had become quite familiar with Paul's writing over the years, having developed a sense of his sonic sensibilities and his descriptions of those notions. But this time it was different. What struck me was the manner with which he conveyed his very favorable impressions of the D-Premier. It was not a case of one word or one sentence. It was the Gestalt of the review that was the slap to the upside of my head. It left me convinced that, with the D-Premier, Devialet had a product that was nothing else but extraordinary. 

Just like that, I was in the "had to have it" mode.

There was a problem however: Devialet was so new to the game, that they had not yet set up distribution in the US. I searched high and low and finally purchased a D-Premier from Audio Plus Services in Canada. 

The D-Premier has been my go-to component in my reference system ever since.

Serious Misgivings

Over the ensuing years, I noticed a trend—the D-Premier was losing value. And at an uncomfortable rate no less. 

When I look back, I am quite sure that this decline had a lot to do with the fact that Devialet had been steadily adding new and improved amplification models to their product array. 

No matter, I felt short changed. I could not shake the feeling that the depreciation of the D-Premier was unusual and something very unsettling. 

When new, the  D-Premier was priced at $15,999. Lately a D-Premier can be had for something like $3000.

I was not a happy camper. 

Life Is Good

My misgivings were significantly blunted recently when I learned that Devialet had instituted an upgrade program for the D-Premier.

For a $5190 fee Devialet will take a D-Premier and turn it into an Expert 250 Pro with an asking price of $18,990. And provide a new 5 year warranty to boot.

Now we are talking! It sure looks like an offer that can't be refused.

Think about it. Here, in one fell swoop you can go from your years old D-Premier and end up with the very best that Devialet offers, the Expert 250 Pro. 

Obviously, the procedure of converting a D-Premier into an Expert 250 Pro is a very extensive transformation requiring specialized skill. Basically, the complete guts of the D-Premier are removed from its case, something in itself very special since it has been machined from a solid aluminum billet, only to be refilled with a completely new set of the Expert 250 Pro electronics. That is why this demanding  process is assigned to the Devialet facility in Paris. The turnaround time is 20 working days according to their website..

Unfortunately, my financial situation precludes me from getting the upgrade at the moment.

But luck was on my side when an opportunity came up where I was able to spend some serious time with an Expert 250 Pro in my system. I used this good fortune to compare it to my D-Premier and observe the benefits of the conversion. 

Inside The Expert 250 Pro

As the king of the hill of the Devialet product lineup, the Expert 250 Pro has numerous areas that have been significantly upgraded. These improvements show up as substantial gains in performance and significantly expanded functionality.

Here is a look at some of the more significant technical advances that have been implemented in the Expert 250 Pro. 

The groundbreaking ADH hybrid amplification now appears in a newly upgraded iteration. 

The Class A amp design has been simplified to the point where the signal now crosses only 2 silicon junctions resulting in a significant reduction of THD. Additionally, the Class A amplifier has an increased sense from 8 bits to 10 bits resulting in 1024 levels, up from the previous 256. 

The recent version of the Class D amplifier features optimized efficiency. Without any increases in size, it is now capable of supplying 50% more power. 

The capacity of the main Power Factor Corrected power supply has been increased and made more responsive. This power supply now continuously adapts to the demands of the music playing and, as a result, allows it to perform with greater energetic efficiency. Additionally, it is now capable of delivering 4000 W of peak power. The new power supply has notably improved decoupling of 15dB from the mains network. 

To achieve more gain in the ADH loop, the number of inductors has been increased from 12 to 14. 

The Core Infinity board has been further integrated and the distribution of the clock has been optimized to yield much lower jitter.

The Expert 250 Pro will support the following streaming software: UPnP, Airplay, Spotify Connect. And it is ROON ready. 

The Magic Wire DAC has been reworked by reducing the number of transistors to realize significantly lower the harmonic distortion over the full operating bandwidth. This results in an improvement of THD by more than 6dB and lowers the noise floor by 2.5dB.

And Then There Is SAM®

I want to pay very special attention to Devialet's Speaker Active Matching, or SAM® for short. 

According to Devialet: "SAM® is an electro-acoustic revolution. For the first time ever, Devialet SAM® technology guarantees a seamless match between your amplifier and connected speakers."

SAM® is an innovative technology of great sophistication, and is a singularly effective design that dramatically optimizes speaker performance. It was developed in-house and is only available from Devialet for their amplification products. It's a process that operates in the time domain in the frequency range below 150Hz. 

It all starts with a logistically challenging effort of epic proportions. During a span of years, Devialet has been continuously obtaining a wide variety of loudspeaker models from numerous manufacturers. Employing laser technology, they proceeded to perform sophisticated measurements of specific transducer characteristics and behavior for each speaker in a fully activated state. In addition, an assessment of electrical and acoustic characteristics is performed. All these very challenging and elaborate tasks have been executed at Devialet's Paris facility. 

The resulting immense database organizes these specific and unique measurements and correlates them with each particular loudspeaker. Presently this database contains more than 900 SAM®-READY speaker models. 

SAM® functions by recognizing the exact specifications of the particular speaker model in use and then, using DSP, provides, in real time, at a rate of 96,000 inspection points each second, a drive signal specifically tailored for that speaker. The level of effectiveness of SAM® is variable and can be adjusted with a setting selected in the remote control.

Included in the scope of SAM® is speaker protection. If a drive signal is detected approaching the Safe Operating Area of a loudspeaker, the drive signal is adjusted on the fly to a level that will not damage the speaker.

This is how Devialet describes SAM®: "A mathematical model of the complete loudspeaker, accounting for the electrical, mechanical, and acoustical behavior (crossover filter, speaker driver, acoustic load) is running in real time on a DSP, that is like the brain of the Devialet. It computes for every sample the exact voltage that has to be applied to the loudspeaker input by the power amplifier, so that the acoustic pressure is a one-to-one image of the audio signal."

To initiate SAM®, the user selects the speaker model in use and, using the Devialet Configurator function, programs the selected model into the Expert 250 Pro. This directs the DSP of the Expert 250 Pro to calculate and provide, in real time, a unique drive signal customized to this speaker's specific characteristics so that the speaker can perform as close as possible to its optimum ability. The end result is a seamless match between amplifier and speaker.

When Devialet started out to compile the required information for SAM®, it would take days to complete the elaborate set of specific measurements for each speaker. Never one to stand still, Devaliet has consolidated this whole complex analysis process into a portable and expedient device: the SAM Lab. This accessory, that comes in a package the size of a briefcase, is a portable device that can be easily transported to perform the complete SAM® analysis anywhere, like a client's house or dealer showroom, eliminating the need to bring the speaker to Devialet's facilities. 

But There's More 

In addition to SAM®, there are several Devialet technologies that significantly increase the performance capability and flexibility of the Expert 250 Pro.

CORE Infinity brings a number of streaming protocols to Expert Pro such as UPnP renderer, AirPlay, and Spotify Connect.

MAT® - Minimal Arithmetic Transform - Minimal Arithmetic Transform works to make DSD playback more competent. MAT® is a DSD Engine technology that supports DSD 64 on USB and every high speed PCM digital input through DoP v. 1.0.

Devialet has singled out Vinyl lovers for specific consideration by paying special attention to the phono stage and providing useful options for the LP user. 

Phono Stage Choices. The selections available cover the ability to select a moving magnet and moving coil cartridge, or stereo and mono settings, and provide provisions for resistive and capacitive loading possibilities. 

RAM® - Record Active Matching provides a choice of equalization curves and other variables to adapt, on the fly, the Devialet phono stage of the Expert 250 Pro to each exact vinyl LP.  The equalization curves: RIAA 1953, RIAA 1976, NAB, RCA, COLUMBIA, EMI, AES, DECCA, L'OISEAU LYRE, TELEFUNKEN, CAPITOL, MGM, and ESOTERIC.

I feel that the level of sophistication of the technology and the amazing flexibility provided in a product like the Expert 250 Pro, is, for me, in the mind-boggling realm. The vast majority of these accomplishments are only possible because of the very significant advances made in Digital Signal Processing, or DSP.

Thank you DSP! Digital can do in its sleep what analog can only dream about.

Here's How I Did It

The evaluation procedure could not be more simple. Since the D-Premier and the Expert 250 Pro have identical outside dimensions, and with gain settings the same for both, it was just a matter of a simple substitution of the two units. My D-Premier is supported by a Star Sound Technologies Sistrum model SP-101 platform which sits directly on the concrete floor of my listening room. For each swap I simply disconnected the D-Premier and replaced it with the Expert 250 Pro. And then back again. And so on.

When it comes to getting the most from the D-Premier, I have found that the Furutech NANO FP-559 AC power cord does wonders. It is also what I used to power the Expert 250 Pro .

The rest of the system consists of an Aurender N10 Caching Music Server/Streamer or a Laufer Technik MP64 Memory Player (designed by Mark Porzilli), and the Revel Salon 2 loudspeakers. The S/PDIF cable is The Reference XV-5 Ultra from Chris Sommovego's Black Cat Cable Company.

I used two speaker cables: Basis Audio Signal Science Labs Cables Model Extreme Biwire and the Cardas Audio Clear Beyond Bi-wire.

The Cardas Clear Beyond cables played an exceptionally useful role. They provided an inordinately transparent path from the Expert 250 Pro to the Salon 2 loudspeakers that allowed me to get to the heart of the extraordinary performance capabilities of this amplifier.

Room treatment consists of a number of Acoustica Appllicata DaaDs and 4 units of Shakti Innovations Hallographs.

Bottom Line, A Prologue 

When all was said and done, the Expert 250 Pro outperformed the D-Premier handily by being better in an all-encompassing manner. No surprise there.

The task now is to convey how much better.

To help me accomplish that undertaking more effectively, I will rely on some of my impressions of the D-Premier performance as I expressed them in my original review that appeared in Positive Feedback in Issue 67 (HERE).

No matter how you pick it apart, the ambient cues, the most subtle instrumental shadings, the micro and macro dynamics are revealed aptly proportioned to communicate the joy that music is intended to convey.

When we are in a concert hall listening to a performance and the music gets to be really dynamic and intricate, thoughts about clarity or purity of sound are just not there. It is taken for granted that this is how things are; it's live, it's unamplified, it's something that is to be expected. It is a reality. It all adds to the drama and expression of the music, but not because it is really pure or clean.

Well, listening to music with the D-Premier is very reminiscent of these types of presentations of purity and seemingly effortless clarity. If the recording captured that intangible "it", the D-Premier was there to recreate it. It was that same effortlessness and, yes, simplicity, that allowed it to replicate the dynamic and harmonic complexities with an ease reminiscent of the live event.

It approached that elusive spring-to-life aspect more closely than any other audio component in my experience. It exhibited a vivid vitality aglow with a sonic presence that was captivating and energizing.

The way I hear it, it's all about speed. More speed means more bandwidth, more bandwidth results in more information. The trove of sonic trivia, the shadings, the intonations, the subtleties, the spatial relationships, were not only revealed, they were now thoroughly versed and clearly delivered in a very profound, yet refined, manner.

What sets the D-Premier apart is its ability to convey the sense of the starkly sudden leading edges of transient attacks that allow us to relate to the dynamics of a live situation. Be they guitar plucks, rim shots, or brushes caressing a cymbal—that ability to replicate the immediacy and speed is the prominent aspect that takes the D-Premier to that exceptionally lofty performance level that distinguishes it from the rest of the crowd.

I feel that the sonic behavior of the D-Premier as I described it then is very much the same today.

The test conditions now and then have remained quite static over the years. Same room, same room treatment, same speakers. The MP64 Memory Player has been updated, and the speaker cables are different. Source material still all digital. Since I am now using many of the high-res files available from Qobuz the equipment is tested in a more sophisticated manner.

The Bottom Line 

The Expert 250 Pro performed more convincingly and more competently in every one of the situations considered in my vintage D-Premier review comments. 

There are, however, several sonic aspects of the Expert 250 Pro that need to be highlighted. They should be considered like exclamation points that single out the areas that reveal the grand level of performance achieved by the Expert 250 Pro.

At the same time I feel that I am doing it a disservice by dissecting its capabilities because what the Expert 250 Pro actually accomplishes is something exceptionally seamless and remarkably effortless. The listener is captivated in an all-embracing manner and not because of a single fascinating aspect. 

The Expert 250 Pro appears to perform as a unifier of a multitude of sonically desirable facets by allowing them to flow and culminate in an naturally fulfilling, exceptionally spellbinding exhibition. 

Mind you, it's not just a matter of the whole being more than the sum of its parts. What I am talking about is the manner in which the parts get summed to get to the whole. It's the sophisticated level of refinement that is in play to convey how the particular parts are summed during the shaping of the whole.

With the Expert 250 Pro, the presentation of the stereo image appeared as wide as I have ever encountered. This exceptional horizontal dimensionality was appealingly enhanced by an exacting depiction of depth that culminated in a dimensionally credible perspective.

The placement of each performer was clearly defined laterally as well as depthwise. Each one appeared specifically located in the soundstage where every individual materialized enveloped by a seemingly personalized soundspace. 

This kind of soundstage, earnestness is a testament to the remarkable resolution capability of the Expert 250 Pro. 

It is also capable of uncommonly refined feats of power. The Expert 250 Pro, depending on the music, of course, can be called upon to deliver some serious heft. This was not merely an execution of dynamic power, this was a case of carefully controlled clout. It was a musical adventure that was tactile, deliberate, and delightful.

Such tour de force exploits could be counted on to bolster the more exuberantly cascading musical scales to become very credibly rendered and thus increasing the level of engagement of the performance.

Then there's effortless. This is one essential characteristic that I had always appreciated at the achievement level of what the D-Premier was able to do for all these years while I have used it. 

With Expert 250 Pro, the musical presentation was taken to another level. What I heard now was not only singularly more resolved, there was also an atmosphere of delicacy that culminated in a new level of musical refinement. The music appeared weightless. It just hovered there, appearing to float suspended in space.

This all-pervasive effortless élan was present regardless of the payback level or musical complexity. The music appeared to flow with exceptional freedom. I had the feeling on numerous occasions that I was experiencing an indescribably close rendering of the gist of the actual recorded event.

Decisions, decisions.

What to do? 

That I will not tell you.

I am, however, confident that I have provided a very generous amount of information and related an extensive array of impressions that should aid you in evaluating the situation and allow you to come to your own decision.

There is no doubt in my mind that the upgraded D-Premier is something that is a significantly accomplished entity. After all, that's the Expert 250 Pro, the very best that Devialet offers.

Better performance? YES! More flexibility? YES! More features? YES! A new 5 year warranty? YES!

For $5190, all that can be all yours.

Your call!

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