Devialet Expert 140 Pro Amplifier

Prologue

Mei impatiently twirled the ends of her long hair as she waited for Joe outside The Adelphi - Mecca of all audiophiles in Singapore. Minutes later, Joe appeared in a huff and drenched in perspiration - the humid tropical weather was especially unkind to office workers in their impractical attire.

"Took a leisurely walk here Joe ?" Mei commented sarcastically before defusing the sharp edge of her words with the sweetest smile ever.

Joe ignored her remark and quietly opened the door, heading straight for the shop that carried Devialet products. Mei had tasked him to find a suitable stereo system for her and he thought this fit the bill even though it was too much of a compromise by his exacting audiophile standards.

Mei and Joe were welcomed into the shop (Joe was a regular customer there) and after some refreshments, the salesperson ran them through the features of the Devialet Expert Pro amplifier. Mei sat down on the sofa with Joe standing behind her. She scrolled through the iPad lying on the sofa and within a minute, her favourite tunes were playing sweetly through the speakers in front of her. She twirled the knob of the remote control a few times and nodded approvingly. After a few tracks, she got up and walked over to the Devialet amplifier that was sitting on the top shelf of the component rack. She brushed her long slender fingers on the beautifully chromed chassis. It looked like a futuristic slab of metal, with just a single small circular window breaking the uniformity of the top panel.

"This is a very beautiful piece of art. Will you help me set it up ?" Mei smiled at the salesperson with her dimples barely showing.  

"Ah! Of course Miss. We will set up the whole system for you. If you have an existing music library your boyfriend can help you connect it - it's really easy." The salesperson could smell the scent of a pending sale and the soon-to-be-earned commission was already warming the cockles of his heart.

"Boyfriend? Please!" Mei dismissively replied while rolling her eyes disapprovingly. Joe blushed at both the salesperson's words and the sting of Mei's response.

"It's a digital amp and you are paying a premium for a lifestyle product!" Joe protested at Mei's impulsive decision. Mei ignored Joe and continued to stroke the Devialet lovingly.

Thankfully, the salesperson managed to close the deal and the Devialet was delivered promptly to Mei's home with other components to make up her minimal and very tasteful music system.

Introduction

Mei and Joe are fictional characters, but there are many music lovers like Mei. They want a beautiful and good-sounding amplifier that can fit nicely into a modern home. Too many audio components look like something from a mad scientist's laboratory, or the control panel of a nuclear reactor. 

My very first experience with Devialet dates back many years ago when the D-Premier was first launched. A fellow audiophile was very eager for me to listen to it, and he turned up at my doorstep with a large flat box under one arm (don't try this with conventional amplifiers!). It was an impressive experience, with a laidback and slightly warm sound that was more than powerful enough to power my speakers then - a pair of Focal Diablo Utopia bookshelf speakers. Positive impressions aside, there were some glaring omissions in my opinion, the prime ones being unstable wi-fi streaming and a lack of a USB port. 

Was the D-Premier equal to my stack of components which were of equivalent value? Like a directionless corporate meeting, we respectfully agreed to disagree. He preferred the D-Premier, while I preferred my clumsy stack of components. He mischievously reminded me that the D-Premier was cheaper by a significant margin once I took into account the many footers, cables, power cords and rack space involved with my traditional stack.

The D-Premier cost close to S$ 20,000 when it was first released in Singapore. Thankfully, Devialet has worked hard over the years and the entry-level model (the subject of this review), the Expert 140 Pro is much more affordable.

Description

The Expert 140 Pro retains the sleek lines of the D-Premier. It is sexy enough to elicit envious glances from the most jaded audiophile. It has a more than passing resemblance to a high-end bathroom scale, and can even be mounted on the wall if you so desire.

A small port window shows various information including volume, source, and the status of SAM, and network connections. A single button powers up and shuts down the unit, while a sleek remote control controls commonly used functions (or as customised by the user).

Beauty here is not merely skin-deep. The Expert 140 Pro packs impressive amounts of technology and integration. Apart from being a powerful integrated amplifier, it also contains a DAC, phono stage (both MM and MC) and streamer. 

The most controversial design point is that everything is handled in the digital domain. In the case of the phono stage, or analog input, the signal is converted to digital using a high quality A/D converter. Listening to your records after it has been digitised ? Sacre Bleu !  An optimist would of course focus on the benefits of having the signal in the digital domain, including the ability to process the signal using powerful DSP. Devialet is able to do this for both the partnering record cartridges (RAM) and speakers (SAM). The digital heavy lifting is carried out using a Quad-core 1 GHz CPU and 2 X SHARC 400 MHz DSP units.

Despite the compact form factor, the Expert 140 Pro packs a powerful punch. Power output is 140 W per channel into 6 ohms. Amplification is achieved with a hybrid design that combines a Class A amplifier (providing voltage amplification) with Class D modules (providing current). In a way, this concept is similar to the current-dumping design launched by Quad in 1975 which combined a Class A amplifier with "current-dumping" transistors to supply the necessary current. Class A designs are required to dissipate tremendous amounts of heat and a design that could deliver power equivalent to the Devialet would be massive and put out enough heat to warm a small room! 

RAM and SAM

Record Adaptive Matching (RAMⓇ) is available in the Expert 220 Pro upwards and the Expert 140 Pro only allows a choice between MM/MC and adjustment of sensitivity. RAM allows the user to choose more than 256 combinations of resistance and capacitance, as well as a choice of equalisation curve. 

Speaker Adaptive Matching (SAMⓇ) is a complex compensation model that attempts to correct sub-optimal speaker behaviour. Devialet measures the speaker in question to create a map of more than 60 parameters. The model is derived from measurement of the crossover network, speaker driver displacement, deformation, maximum displacement, speed and acceleration. Speaker models are continuously added to the SAM database, and the current database stands at more than 900 models. Conveniently, both my Vivid Giya G4 and Tannoy Kensington GR speakers are listed in the database. 

A worthy mention is that SAM allows extension of your low-frequency response, with sensible protection built-in to prevent you from blowing up your speakers. It can be switched in and out on the fly using the remote control. By configuring your remote, it is possible to adjust the level of SAM correction from 0 % to 100 %.

Configurator

An online configurator allows you to set up your Devialet according to your preferences. You can configure your inputs to be either digital or analog (either line-level or phono), and apply SAM, and phono settings too. 

This is just scratching the surface of what the configurator allows you to do. You can also (this is just a shortlist of features available) customise your remote control buttons, adjust the sampling rate of the ADC for analog inputs, set individual sensitivity levels, and adjust the maximum power output allowable from the unit.  

The configuration file is then saved onto an SD card which is inserted into a slot at the back of the amplifier. You could create multiple configuration files to be saved on different SD cards should you wish to show off your amplifier in another person's system. 

Operation and Ease of Use

Getting the Expert 140 Pro up and running was quite easy, save for the scare I got from the non-responsive remote. It turned out that the installed batteries were dead even though my unit was brand new. 

The compact dimensions do require you to use a power cord with a slim IEC and banana plug terminated speaker cables. In an all-time first, an entry level Audioquest power cord is supplied in the box. In case you insist on using your massively sized power cords, a removable rear plate allows you to do this, losing a bit of stylishness in the process.

I never got the Devialet to stream from a DLNA server source, and neither did I install Devialet Air (the companion streaming software) as this runs on a personal computer (which I do not use in my main system). Instead, I used the Devialet as a Roon endpoint where it worked seamlessly. You can also use Airplay and Spotify Connect if you want to.

I did have the odd occasion where the Devialet failed to detect the SD card upon start-up. However, powering the unit down and re-inserting the SD card solved this. I found it odd that Devialet used such a primitive method of configuring the unit when everything else about the unit is technologically light-years ahead of the competition. The configuration file is a text file that can actually be viewed and edited, which seems dated. It would have been nice to be able to configure the Devialet using an app instead. Instead, the free app works as a substitute for the remote control. 

My remote also had an issue with batteries, eating up fresh alkaline batteries every 2-3 months on average. No wonder, the factory-supplied batteries were flat on arrival! I've read of other users having similar issues, and this apparently can be fixed by the factory.  

Sound Quality

The Devialet appeals as a lifestyle product and brings with it the misconceptions of an overpriced and inferior product. Actual use (I've had my set for more than two years) proves that this is a highly versatile product that is a viable and attractive alternative to a stack of components with spaghetti cabling everywhere! I have brought the Devialet along to listening sessions in other setups where they have always acquitted themselves, even against very expensive equipment.

The Devialet does have a subtly sweet and rich tone that is pleasant and inviting. The Class D detractors would have to leave in disappointment at this juncture. The midrange in particular is sweet, smooth and laidback. The bass quality is good, with power and a full textured midbass. In fact, you could argue that the Devialet takes the polite path rather than a sharp, or hyper analytical route. The high frequencies are also cleanly reproduced, without any noticeable evidence of roll-off or anomalies from the low-pass filter required for Class D designs to filter out ultra-sonic noise.

I would rate the Devialet's performance as reasonable for the price. However, enabling SAM lifts it up significantly. Apart from the very obvious boost in bass extension and power, there is an increase in focus and coherency that makes it very hard to revert back to SAM-less listening. Play it again Sam!  

Conclusion

The Devialet is a superb all-in-one that demonstrates that convenience need not come at the expense of sound quality. It's a pity that traditionally-minded audiophiles may not give the Devialet due consideration. 

With shrinking living spaces in Asia, this is the perfect product that ticks all the boxes :- looks, convenience, quality and price. Some may disagree that the Devialet is an affordable product, but I am convinced based on the many boxes it replaces, and the outstanding sound quality it delivers - Highly Recommended.    

Epilogue

Mei sat gracefully on her sofa, listening to music from her new sound system. Joe had managed to convince her to install the Expert 140 Pro amplifier on top of her cantilevered TV rack. Discrete cabling ran to two very slim floorstanding speakers. The system was a perfect foil to Mei's character - graceful and elegant.  

Her music collection had been ripped and stored on a dedicated Intel NUC PC that functioned as a Roon server. Joe had also subscribed to Tidal in case Mei wanted to explore new music just like she did when she came over to his home.  

Standing up, Mei surveyed the very neat job that Joe had done in arranging everything. Her long flowing white dress showed off her slim waist and she glowed like an angel. Joe's heart skipped a beat and he bit his lower lip hard.

Devialet Expert Pro 140 Amplifier

Price : S$ 8,990 

  

        

Markaudio-SOTA Tozzi One Speaker Kit

Introduction

The Tozzi One speaker kit is likely the easiest speaker kit on the market. I assembled it in an hour, half of which was spent looking for my tools, and cleaning up. This is the perfect kit for beginners as there is no soldering involved - all you need is a screwdriver. 

The kit costs USD 395 per pair if purchased direct from the manufacturer, but it can sometimes be found cheaper from other merchants. 

Description

Based on their in-house CHN 50 full-range driver, the Tozzi One is built around an ABS and fiber-reinforced cabinet. 

The driver is mounted in a shallow wave-guide, while the cabinet is rear-ported. Sensitivity is rated at 85 dB, and impedance at 6 ohms. The anechoic frequency response is specified at 80 Hz - 22 kHz (+/- 6 db). The cabinet measures 200 x 126 x 200 mm, and weighs 1.42 kg. The cabinet is angled up slightly, so you should be fine listening to it in the near-field while placed on your desk. 

The waveguide has a textured finish, while the sides of the cabinet are finished in a faux leather wrap. 

Assembly is straightforward enough. The instructions were in Japanese, but the diagram is clear enough to figure out. 

A thin gasket is placed between the front baffle and the speaker driver. The driver is held in place with five hex nuts. The supplied wiring is terminated in push-on terminals and o-rings, so you just need to connect them to the speaker driver and supplied five-way binding posts. The rear panel foam needs to be affixed using the supplied double-sided tape. Install the gasket into the rear panel groove, and attach it to the speaker cabinet with screws. That's it! Building and programming a custom keyboard is far more challenging than this. 

The beauty of full-range driver designs is that there is no crossover to mess around with. From a technical viewpoint, you get the best possible coherence from using a single driver and higher efficiency and purity from skipping the passive crossover. There is no free lunch though. Asking a driver to cover the whole frequency range results in uneven response. Most designs have to rely on complex cabinet designs with some form of a back-loaded horn to get usable bass output. 

Sound Quality

Straight out of the box, the Tozzi One has a clear and engaging sound, but with some rough edges. A few hours of run-in sorts that out nicely.

As expected from a full-range driver speaker, you get a lovely transparent and coherent sound. The Tozzi One sounds bigger than it looks although the very limited low-frequency output and extension makes it more suited for background listening in a large room, or listening in the near-field. In a large room, you definitely need to pair this with a subwoofer.  

Fast forward a month later, and the Tozzi One has had everything thrown at it while it sat on my computer and work desk - gaming sessions, background music, serious listening sessions, etc. As desktop speakers and with proper amplification, the Tozzi One will eat your computer speakers for lunch. I paired them with a spare Kingrex T20U amplifier that I happened to have lying around. The Kingrex delivers 10W per channel into a 4 ohm load and is enough to drive the Tozzi One to fairly loud levels for near-field listening purposes. I found it to have enough grunt to make explosions, gunshots, and orchestral crescendos equally satisfying. The rest of the frequency range was handled quite well without the midrange honk or peaky top-end that I sometimes hear from full-range drivers. In fact, the midrange is laidback and on the warm side of neutral. 

Where the Tozzi One really nails it is staging and imaging that is both spacious and pin-point. There is plenty of soundstage width, depth, and a good sense of dimensional layering.  

 

Conclusion

The Tozzi One is an excellent addition to my work desk. With the present world situation, this may be just the thing you need to preserve your sanity during long work-from-home stints. It may need more effort to set up than the usual powered speaker suspects, but it is well worth it.

MarkAudio-SOTA

http://markaudio-sota.us/

Price : USD 395 per pair

Elekit TU-8600R Integrated Amplifier

Introduction

Problem Statement - You want a quality integrated tube amplifier, but no means to afford one. No problem, just build your own ! Assuming you have decent soldering skills, and are not instruction-intolerant (sadly, that rules out my teenage daughter), the Elekit TU-8600R lets you enjoy quality on the cheap. You will need about four full days to build one, but the effort is well worth it.

Description

The Elekit TU-8600R is a 300B single-ended integrated tube amplifier kit from the nice folks at Elekit of Japan. The TU-8600R is neither a basic kit nor design, and has parts quality and design features found in high-end models.

The power transformer is a high-quality R-core type, with low magnetic flux leakage. The solid state rectification uses Schottky fast recovery diodes. The power supply circuit includes ripple filters and plenty of regulation stages. An active automatic bias adjustment system means no fiddling with bias pots, and optimal sound quality at all times.

Parts quality is generous with plenty of Japanese branded resistors and capacitors. The PCB thoughtfully provides sufficient space for you to install large boutique coupling capacitors too. After all, isn't that the whole point of DIY, the freedom to express yourself ?

The TU-8600R's circuit is based on a single 12AX7 input tube, which then feeds dual 12AU7 tubes. The latter's two triode sections are wired in parallel to drive the 300B power tube. The output transformer has speaker taps for both low and high impedance speaker loads (selectable by a switch on the rear). A headphone socket allows you to enjoy your Elekit with your favourite pair of cans. Jumpers on the PCB allow you to adjust the headphone output level, and the colour of the power LED.

Although the TU-8600R is an integrated amplifier, there is only one set of RCA inputs. This could be a deal-breaker for some, although you could purchase or build an input switching box to get around this. 

Build Experience

Elekit gets first prize for having the best instructions I've ever received with an audio-oriented kit. The instructions rely on very clear diagrams and steps to guide you every step of the way. The PCB is marked clearly and even reminds you when components are required to be installed on to the reverse side of the board. Plenty of due care and consideration went into ensuring that the assembly is as painless as possible. 

The sheer parts count and complexity of the PCB makes this project highly unsuitable for a first-time build. The soldering of the transistors was the most delicate part of the build, as the solder pads are dangerously close. I would also highly recommend that a temperate controllable iron be used. 

In my case, I chose to upgrade the stock resistors to Takman Carbon film ones, and the coupling capacitors to Amtrans AMCY Golden Black. I also bypassed the volume pot and wired the input jacks directly to the main PCB. The input sensitivity will be high, but if you are able to adjust the output level on your source (e.g. a DAC with volume control), you should be fine. 

Starting off at the professional assembly area a.k.a. dining table.

The Takmans are too large to fit and the legs have to be bent in a curved fashion to fit the board.

Soldering of the resistors is complete.

Plenty of space for upgrading the coupling capacitors.

This is the top side of the board. The main circuit is on the underside.

Testing phase. I made a boo-boo here. 

Running-in phase. 

The only mishap suffered was when I wired the input wiring to the wrong solder pads. I happily soldered them to the input pads. They should have been wired to the output pads instead (Elekit refers to them as output pads in the sense that they receive the output from the potentiometer). 

The power and output transformer connect to the PCB via push-on Molex connectors. Since the stars were aligned, I decided to run in both the stock output transformers and the Lundahl ones which are optional. 

One criticism I have is with respect to the sheet metal covers. They have a fair amount of ring, and degrade the sound quality. This was very noticeable when I installed both after my run-in process was completed.

Sound Quality

Paired with Genalex 300B tubes and a variety of 12AX7 and 12AU7 tubes from my stockpile, I gave each set of output transformers about 10 hours of run-time before I did any critical listening. I used my Totaldac DAC (using digital volume control) and icOn4 Pro as preamplifier, and my Vivid Giya G4 speakers. 

The Elekit is highly detailed, fast and open. The tone is light and clear, so if you are seeking the vintage 300B tone (warm, full and midrange-centric) you should look elsewhere. Despite the low power on tap, vocals and smaller works were an absolute treat with the Vivid. While the midrange was not overly liquid, the presentation was clearly in the tube amp camp. 

Soundstaging and imaging was holographic with pinpoint placement and excellent depth and width. The bass control and dynamics were satisfactory, but this is not the reason why you choose a single-ended tube amp. I believe that given the right set of loudspeakers (i.e. high efficiency), the Elekit would have no problem bringing the house down.

Swapping in the Lundahl transformer is the point where the Elekit is transformed from competent to world-class. The gains in detail retrieval, control over both ends of the frequency spectrum and refinement make the Lundahl a solid investment proposition. Elekit supplies the stock transformer even if you opt for the Lundahl, so you could always upgrade in the future, only losing out on having additional shipping costs.

The Elekit is good enough to be your end-game amplifier unless you suffer from equipment polygamy (which Audiophile doesn't ?). I was heartened to find such high quality at an affordable price, knowing that many would be able to enjoy its fine musicality.  

Conclusion    

There is a sense of rightness to the Elekit, and there is the invaluable ability to dial it in precisely to your taste through judicious choice of parts. 

It comes in at an attractive price tag, so the only real downside is that you need to spend the time and effort to build it yourself. However, most Elekit dealers would offer a build service for a fee, or be able to refer you to someone who could. Best Buy and Highly Recommended.

Elekit TU-8600R Integrated Amplifier

Price - POA

Elekit kits are available from :-

Horizon Acoustics

1 Pemimpin Drive

#08-11, One Pemipin

Singapore 576151

http://www.horizonacoustics.com

Astell&Kern USB-C Dual DAC Cable

Introduction

Chances are that you use your notebook, tablet, or mobile phone to play music, especially through a streaming service like Tidal or Spotify. Sound quality is typically poor or mediocre. Integrated audio chips work in noisy electrical environments, and usually lack the necessary power to drive high-quality headphones. 

Astell&Kern have released a USB-C DAC / headphone amp that provides an instant boost to your sound quality and lets you use your 3.5mm wired equipment with devices that lack a headphone jack, like some of the new mobile phones.

Description

The USB-C Dual DAC Cable ("Dual DAC") is based on twin Cirrus Logic CS43198 MasterHIFI Digital-to-Analog Converters. The CS43198 is a Delta-Sigma oversampling DAC that supports up to 384 kHz sampling rate / 32-bit resolution for PCM and DSD 256. 

As expected from an Astell&Kern product, the Dual DAC is finished to a high standard. The compact metal Zinc alloy body (it is no bigger than a thumb-drive at 50 mm x 17 mm x 10.3mm !) houses an integrated circuit with bespoke designed capacitors and an optimised audio circuit to minimise power fluctuations and provide premium sound quality. 

Astell&Kern claims that the analog amplifier is powerful enough to drive a variety of high impedance headphones with a 2V rms output level (condition no load). Output impedance is suitably low at 2 ohms, which should ensure lower distortion into low impedance headphones. 

The fixed cable is a durable 4-core cable made out of a core of Technora aramid fiber, with a layer of thick silver-plated copper wrapped around it, followed by a further layer of copper wire in a spiral arrangement. The tastefully angled housing is carried over to the matching USB-C connector. A single LED indicates operation, while volume is controlled through the device it is paired with. 

Operation

The Dual DAC worked without any issue with a variety of devices I tried - a Samsung Galaxy S10+ mobile phone, a Windows 10 notebook, and a 2020 Macbook Pro notebook. The bulk of my listening was done on the Samsung, playing music either through the Tidal or USB Audio Player Pro app. Power-draw was modest and I did not notice any adverse impact on battery life. Sadly, the Dual DAC is incompatible with iOS devices due to current limitations through their ports. Both high-resolution PCM and DSD files played without any issue.

The USB-C connector is quite large and may not fit properly through your mobile phone case. My case cut-outs were not big enough and I had to remove my phone case to plug in the Dual DAC. I am in two minds about the fixed lead. I like the idea of a fixed cable, but it is quite short and in the case of my Windows 10 notebook, the USB ports are located on the side of the screen, which left the Dual DAC suspended in the air.

Sound Quality

The Dual DAC provided a significant uplift in sound quality and drive capability, with the improvements most noticeable on difficult to drive headphones. I tried it with a variety of IEMs, as well as two headphones - a Beyer DT880 (250 ohm version) and an E-MU Teak. Most of my listening was done on the E-MU for reasons explained below.

The most striking improvement was in the reproduction of low-frequencies. The Dual DAC added a tight punchiness that went deep. Vocals gained clarity and refinement, adding sweetness and uncovering details that were previously obscured. High-frequencies too gained extension and airiness, giving music a brighter and more illuminated tone. The soundstage opened up, with an increase in dimensionality, and the sense of acoustic space in the recording.

Pairing the Dual DAC with IEMs brought improvements in sound quality, but the Dual DAC's strength was in bringing extra current and voltage drive for more difficult to drive headphones (within reason). While the DT880 showed improvements with the Dual DAC, it lacked the dynamic freedom and ease compared to my desktop headphone amps. The E-MU Teak is easier to drive in comparison and was very comfortable with the Dual DAC, even at high levels. Given the compact size of the Dual DAC, this is a reasonable compromise.

I was impressed with the high level of sound quality delivered by the Dual DAC and can highly recommend it to Android phone users who want the best sound quality on the go, or to business travelers that need a high-quality and portable audio rig.

Conclusion 

From a pricing standpoint, the Dual DAC is a premium product that carries a corresponding price tag. The competition offers similar products, some at a lower price point with features like balanced drive capability. I think the pricing is fair, and like any Astell&Kern product, you get lasting pride of ownership. 

The Dual DAC will be available in May 2021 at a retail price of S$ 189- Highly Recommended.

You can purchase the Dual DAC from AV One (https://av1group.com.sg), Connect IT, E1 Personal Audio, Headphones.SG, Jaben, Stereo Electronics, and Treoo.com.