Devialet Expert 440 Pro Dual Integrated Amplifier/DAC Review

It was strange to realize that even though I was constantly using it, I was never actually touching it.

Yet, as the weeks went by, the more it seemed to become an extension of my body – like a hand or an arm: it simply became a part of every day physical machinations I completely took for granted – like waving hello.

Utilizing gestures on a touch screen as one’s only means of interaction with a physical object designed to initiate the playback of recorded music is commonplace now, but a just a handful of years ago it would not have been. Especially, when I stop and think about how I used to interact with my hi-fi and the curated physical music collection its existence was predicated on.

You see, without a record collection, there’s not much use for a turntable – other than as a piece of acoustic-mechanical art. The same cannot be said for the Devialet Expert 440 Pro Dual integrated amplifier/streamer/DAC reviewed here. (When I first spoke with Devialet regarding a review, it was to be the Expert 220 Pro, that morphed into them sending a second unit for me to ‘chain’ to the first 220 thereby creating the Expert 440 Pro, a dual-mono version of the stereo 220).

It used to be that you had a number – large or small – of physical albums (or CDs, just swap disc player for turntable in this telling) which you would organize alphabetically, or by genre, or date bought, or jacket color – you name it – that you would flip though and then choose to play. You’d remove it from its jacket, place it on the platter and cue up the tonearm to prepare for the physical act of lowering the stylus onto a rotating record: A trough of plastic, undulating micro-grooves ‘read’ by a diamond-tipped ‘needle’ passing along the signal for amplification.

I’m sure there are many who are old enough to only acknowledge the modern black magic of connecting a streaming amplifier/DAC with a couple of cables and then instigating playback of dematerialized albums stored on hard drives thousands of miles away via wireless transmission through their smartphones or tablets.

LPs? CDs? For hipsters and old men, right?

Yes and no. I think the two are products of a time and as such, generational in their intrinsic value and cultural identity. I feel lucky coming from a pre-digital, analog-only background to be able to truly appreciate just how advanced the Devialet Expert 440 Pro really is. This is either a one-box (stereo) or two-box design (dual-mono) that packs in all the ju-ju a modern digital audiophile would want now and for the foreseeable future.

Background, build, quality and design

A striking design both inside and out.

As I wrote when the Expert 220 Pro ($9,990 USD) first arrived in December “Devialet has created a box unlike any other, and there’s no hyperbole in saying that the design caused a whirlwind of controversy and awe in the audiophile hobby when it was released almost 10 years ago. The Expert 220 Pro is the latest in a line of radically-styled integrated amplifiers going back to 2010’s D-Premier that are stuffed with exclusive, bleeding-edge technology, hardware/software and their accompanying 100+ patents.”

I still remember seeing the D-Premier for the first time – the old saying ’you only get to make a first impression once’ is an apt one for that inital Devialet sighting. Even though I was a real analog-head, I wanted one immediately, but of course funds at the time would never allow for such an extravagance. I was left to intently pour over whatever online coverage was available and watch the product continue to be upgraded at regular intervals over the years as the company’s research and development advanced.

Fast-forward to 2016 and the ‘Expert’ line is announced: sleeker casework and remote along with a host of hardware and software breakthroughs that in many ways define the company: it’s all about the ability to upgrade. Jump ahead to 2020 and the 440 Pro at $18,900 USD contains the current technical state-of-the-art for Devialet, and is just one step down the ladder rungs from ‘Flagship’ status – claimed by the Expert 1000 Pro Dual ($34,900 USD).

A small physical footprint for huge sound.

The look and design of the Expert series is not for everybody. I’ve heard them described in glowing terms and less-than-glowing terms. I’m firmly in the former camp and think the sleek, future-fi industrial design, and high-gloss chrome finish on the CNC-milled billet aluminum chassis all add up to an iconic piece of abstract high-fidelity art sure to be referenced for years to come. Externally devoid of interactive distractions, each Expert features only a power switch on its fascia and a small circular glass-topped LED info screen/menu recessed into its top plate. Control of the units is handled by either the power switch, the supplied remote control or the Devialet app (and for me, Roon – which was my preferred method of virtual interaction).

Well thought-out chassis design for either horizontal or vertical mounting.

Weighing in at roughly 13 lbs per 220, you’re looking at 26 lbs of reflective chrome all in on the 440 – my lower back approves. Accessing the business end of the Pro means sliding off the rear top-cover of the chassis housing which helps keep the Devialet’s visual lines clean (Caveat: I wish Devialet had rubber isolation fitments, or seams between the main chassis and the rear housing cover as the metal-to-metal cannot help but be resonant). When running in dual-mono 440-mode, however, you must remove the lower unit’s cover to help facilitate wired connections between the two units, specifically in my case, the digital bus link which was achieved with the provided SPDIF cable by Crystal Cable. AudioQuest NRG-X2 AC cords were also provided with each 220 Pro, a nice touch in my book and a smart inclusion on Devialet’s part as every other amplifier I’ve ever received for review came with a generic, black mains cable. The AQ cables, while not as exotic as the Expert Pro itself, feature ‘normal-sized’ terminations which fit on the Devialet’s AC input… a good thing because the PSAudio AC5s I normally use (or AQ Hurricanes I had also have on loan) could not fit in the confined quarters of the Expert’s I/O.

Further isolation seemed to assist in tightening sonics.

The bottom plate of each 220 is a mix of what appears to be hard thermo-dynamic plastic and glass viewports for different sight lines into the multi-patented digital-voodoo going on inside. There are four small, nubbed, rubber isolation feet that are sturdy and well up to the job of keeping each unit firmly planted on a rack, stand, shelf – or one another (I employed a three-inch thick maple, spiked, Butcher Block Acoustics amp stand). After some time settling-in, I used Vibrapods under the lower unit for further isolation because I found, sonically, things tightened up a touch (YMMV).

Cabling connections revealed.

I/O on each unit consists of Coaxial, optical, USB, AES/EBU and Ethernet (100/1000Mbp) on the digital side and a pair of phono and line inputs on the analog side, with dual band Wi-Fi built-in (2.4GHz/5GHz 802.11ac, backward compatible with 802.11a/b/g/n – Bluetooth capability to come… remember, all about the upgrades). The Expert Pro is Roon Ready certified, supports UPnP rendering, AirPlay, Spotify Connect, etc. When in dual-mono mode the ‘chained’ unit’s inputs can only be active via the 3.5mm Trigger connection. I did not use this feature. Of note, every incoming source – including phono or line – gets converted to 24-bit/192kHz before being passed along to the DAC and outputted the 5-centimeter distance to the speaker terminals (shortest distance in the world according to Devialet, which has dubbed it ‘Magic Wire’).

The shortest path between DAC and speaker outlets? Devialet claims five centimetres.

The Expert is built around what the company calls its ‘Core Infinity’ computational platform. This is comprised of a 1GHz-Quadcore ARM processor with 1GB of DDR3 RAM and 4GB of Flash memory. An in-house programmed FPGA (with plenty of space for future code) bolsters the Devialet OS, optimizes “audio-signal routing and reworks clock distribution for minimal digital jitter.” Devialet piled on the headroom by including a second DSP-audio processor – this on top of the motherboard DSP unit for “future signal-processing features.” Three ASRC (Asynchronous Sample Rate Converters) help with the heavy lifting of getting everything to 24-bit/192kHz along with an “improved USB interface tailored to accommodate future audio formats.”

The ADH schematic.

The beating heart of any integrated is its amplification and the Expert Pro is no different. Devialet has been using a steadily software-refined form of what it calls ‘ADH’ amplification, or Analog Digital Hybrid, since the first D-Premier. The principle of ADH is a simple*, yet highly-effective one and offers a unique solution to heat generation and sound quality: an analog (Class-A) amp determines the load’s output voltage while passing off the associated current generation function to a Class-D (digital) switch amp. Having the Class-A ‘master amp’ entrusted with voltage/audio performance and the Class-D ‘slave’ amp with current/power requirements very nicely allows for the superior sonics of Class-A without the extreme heat generation associated with that type of amplification. Class-D runs cool in comparison and is how Devialet can stuff 220 watts into such a small enclosure and still have exquisite sound without burning your fingers off were you to touch the chassis (like some pure Class-A integrated amps I’ve had previously).*and similar to a circuit QUAD developed in the ‘70s.

A SAM visual breakdown.

One of the most interesting of the many technologies patented by Devialet for the Expert line is SAM, or Speaker Active Matching. It works off a mechanical and technical measurement database of more than 60 different parameters unique to individual loudspeaker models. Why? Because loudspeakers designed with multiple drivers have temporal delay between the bass/mid diaphragms and the tweeter due to larger drivers having a slower reaction time to the amplified signal. There’s a lot of things a speaker manufacturer can do to minimize this, but still, it persists – because physics. What Devialet has done is amassed highly-detailed specifications of roughly 900 loudspeaker models through in-house analyzation of enclosures and transducer characteristics. Using a laser to measure driver displacement, deformation, maximum displacement, speed and acceleration. “By measuring passive filters, we can determine resonance (event bass-reflex and passive radiators) while factoring in the overall impact of casing and damping. Once this data is compiled, SAM is able to produce a full physical behavioral model. The collected data also allows us to calculate the transducer SOA (Safe Operating Area). By doing so, SAM offers permanent protection from overload, letting users reach higher volumes than ever before.” More on SAM in the ‘Listening’ section.

RAM – Record Active Matching allows users to almost infinitely dial-in specifics.

Touted by the company as “The most advanced phono stage ever created” the digital-processor controlled RAM – Record Active Matching – phono stage is an OCD sufferer and analog addict’s nightmare – or dream. It allows you to configure, in real time, the phono stage to your cartridge or albums via stereo or mono designation, 13 different EQ curve presets; RIAA1953, Columbia, Decca, RCA, etc., loading (Moving Coil loading from 10 Ohms to 460 Ohms), capacitance (Moving Magnet loading from 0 pF to 700 pF), and max ouput levels (0.10mV to 1.00mV for MC carts in 0.01mV steps and 1.00mV to 15mV in 0.1mV steps for MM). “To custom fit the exact characteristics of your turntable or vinyl records.” This was something I messed with way too much, but it’s addictive and I became annoyed with myself for screwing with it so often. In the end, for critical listening I loaded a standard parameter setting for a cartridge and left it.

The Expert Pro’s isolated, microprocessor-controlled dual power supply is based on a central planar transformer (a “high-frequency transformer used in isolated switchmode power supplies operating at high frequency”) which adjusts to load in real time and is unaffected by the mains input. Capable of 90-240Vac – 50/60Hz, it is globally compliant and designed to shift from 0 to 4,000 Watts “while sustaining an average running power of 1,200 Watts.”

The Devialet Configurator.

The Configurator app is how Devialet has software interfaced with owners to determine exactly how they want the Expert Pro’s inputs to be, well, configured. This has to include the most options I’ve ever encountered to set up a piece of hi-fi gear. The process involves accessing the app online and setting up every input as you see fit, then saving the text file to an SD card (included with each Expert, slot at rear), which you then boot the unit from. You can power-down the Expert, remove the SD card, change your parameters via the Configurator and then re-save them, re-boot and voila. Your Expert is a different beast. Very cool.

AIR made simple.

Finally – I could go on and on about the amount of technology utilized by the Expert Series – I’ll touch on AIR, or Asynchronous Intelligent Route, which allows everything to play wired or wirelessly at 24-bit/192kHz. Two choices for this specified playback protocol are available; asynchronous BitPerfect or asynchronous fixed broadband, “to ensure the best possible service quality in even the most unreliable network environments.” I chose BitPerfect because I’m uptight about such things (I could discern no difference between the two).

Everclear's picture

Rafe could keep these amps around for a while and review speakers like Yamaha NS-5000 and Revel Performa F328Be, for example :-) .........

Kraaijcheck's picture

Wich setting would you use for the addict cartridge? I use max level @ 6,5 / loading high @100 / startup curve RIAA 1976 / sampling rate 96

Rafe Arnott's picture
My settings in the end were: 6.5mV, 150pF, RIAA1976, sampling rate for all inputs was 24-bit/192.kHz.
Kraaijcheck's picture

Thanks for your reply. I’m using an Devialet 200 instead of a 220, does this make any difference for the settings?

Rafe Arnott's picture
It does not make any difference in how RAM handles the settings AFAIK.
agentsmittie's picture

I noticed that you are stacking the amplifiers.

I put my 2 X 220s side by side to avoid electrical interference and heat dissipation.

If I had the choice I would much prefer stacking them for aesthetic reason.

Do you have a view on whether there is any potential issues on sound quality and long term durability?


Rafe Arnott's picture
I had no issues or difference in SQ whatsoever that I could discern from having them either side-by-side or stacked. I stacked them in the end for space considerations because I have a lot of review gear coming through.
jeffhenning's picture

Shame you couldn't get this amp on a test bench.

Regardless, I have a soft spot for equipment this pretty that also really performs.

Shame that don't have a version that sacrifices the phono section for stereo subwoofer outputs.

jeffhenning's picture

... Do also get twice as many inputs?

It seems like an oversight if you can't especially given the proprietary link used.

Rafe Arnott's picture
"When in dual-mono mode the ‘chained’ unit’s inputs can only be active via the 3.5mm Trigger connection. I did not use this feature."