Dual Mono Amplifier Test
Devialet Expert 210 Pro Dual Review
Devialet is one of the most innovative amplifier manufacturers out there, so it shouldn't come as a surprise that they also offer their high-tech amps in double mono configuration. The smallest one is called Expert 210 Pro Dual – which greatly improves upon the many qualities of the single device.
It sounds just like a Radio Yerevan joke: What is better than a Devialet amplifier? Answer: two Devialet amplifiers! And it is even perfectly true, because with the Devialet Expert 210 Pro Dual you don't just stack the two on top of each other, but rather merge the two channels of each stereo amplifier into one to get two separate mono blocks. One of the main advantages is of course the increased power reserves. However, the process offers further benefits, among which the better channel separation is a rather minor one. And since everything is based on the highly innovative, extensively DSP-supported and widely programmable Devialet, you can expect something very special, indeed.
With Devialet's 210 Pro Dual from the latest and comprehensively optimized "Expert" series, one of the first things to notice is the very user-friendly operation. As usual for Devialet amps, the key specifications of the two flat, dark chrome-plated devices are stored on one SD card each, which is inserted in a slot on the rear and can be reprogrammed for a wide range of options via the homepage of the French specialist with relative ease. At the next start, the amps, which by the way hardly reach half the normal hi-fi height even when placed on top of each other, take over the updated configuration. Hugely flexible!
Master & Companion
If you buy the Expert 210 Pro Dual, which comes in two boxes, the Dual is preset so that one amp takes over the "master" function while the other works as a "companion". A briefly appearing note in the circular display when switching on – which in this chip-based concept is more like a "boot up" – provides information about the distribution of roles. Since the entire signal processing is digital, the amplifiers are connected by means of a coaxial digital cable via one RCA socket each.
If you now turn the large volume knob on the simply ingenious remote control, you can watch the decibel level values moving up and down at the exact same time on both devices. All other functions like for example the temperature display, are equally perfectly synchronized. All source devices – whether digital or analogue – must be connected exclusively to the master device. The companion becomes a pure power amplifier. As is usual for stereo amplifiers, which are converted to mono-blocks, the speaker cables are connected to the two "hot" positive leads. This "floating" setup without ground reference is probably responsible for the majority of the superior performance independent of volume in mono operation.
By the way, every owner of a Devialet amp can switch to double mono by purchasing an identical model. The 210 Pro Dual is made up of two 140 Pros – it's all just a matter of configuration. There is however no real quantity discount: if you decide on the Dual set for 9,900 Euros right from the start, you save just 80 Euro.
The fact that Devialet amps, whether stereo or mono, are aimed at the digital generation and new media is not only illustrated by the multitude of possibilities in this sector like UPNP streaming via Ethernet, high-bit-capacity "AIR" WLAN, USB interface and one coaxial and two optical digital inputs. Devialet's Expert Pro-amps are even "Roon ready" and thus open up a whole media cosmos including important streaming services to their owners. In addition, the "Roon" app ran perfectly smoothly with our setup.
It's almost a sin to only briefly touch on the unique and diverse technical and equipment highlights of the 210 Pro Dual. However, for a more in-depth exploration, we would need much more space, and the excellent website provides comprehensive information anyway.
That's why "SAM" should be mentioned here above all. Via "Speaker Active Matching" the amplifier compensates for errors of many speaker models in both frequency and phase range. Currently 984 loudspeaker models are included. These were successively measured individually, and the correction curves can be downloaded to the SD card. The next time the amp is started, it will know what to do. The improvements range from subtle to monumental, depending on the quality of the speaker.
The 210 Pro Dual's single analog input can be used for a high level device such as a CD player, or for a turntable with MM or MC pickup. The trick: Via "Record Active Matching" (RAM), many common MM and MC pickups can be called up online in the "Configurator", so that the phono stage automatically adjusts to them with regard to the connection values and gain. Manual changes remain possible at any time. In addition, you can digitize your analog records with up to 192 kilohertz clock rate, and vinyl freaks have 13 different equalization curves to chose from.
It's almost ironic that all these fascinating and useful features are only the surroundings of the real sensation: the "Analog Digital Hybrid" amplifier (ADH). In a sophisticated, unique circuit, it combines an extremely low-distortion Class A stage with a highly effective Class D amp, which, in conjunction with the compact and powerful switch-mode power supply, develops up to almost 450 watts of impulse power, which is even delivered in a very relaxed way, as we experienced with B&W's full-grown 800D3.
What the mono-double pulled off in the large STEREO listening room was a sensation and was a long way ahead of what an Expert 140 Pro can do solo. In the mono duet, the stage expanded in every direction and the already lively performance gained in radiance, sovereignty and emphasis.
In concrete terms, the amp duo implemented the hearty impulses of Monty Alexander's "Moanin'" with dry, pinpoint accuracy and with unmoved vehemence even at highest levels. "Saturday Night", the fantastically sparkling jazz number of the Red Norvo Quintet with vibraphone attacks bursting like crackers between the speakers, came across impressively live, nimble and at the same time extremely transparent and audible, so that the audience, babbling at some distance from the band, appeared defined in the depth of the room. And with "Malvina" Devialet's homogeneous and fanned out double pack not only met the elegiac mood and the typical timbre of the singer, behind which dark clouds of synthesizer piled up like thunderclouds, but we could actually hear "around" her. We have rarely heard it so vividly, organized and yet of course perfectly placed in the room with great ease. A great performance!
Although this might be obvious, the flat amplifiers should not be stack the on top of each other but should be given a solid base each. That is not only due to reasons of sound quality, but also because they heat up quite a bit during operation. Also, the full quality of reproduction can only be experienced if the correct mains polarity is used – otherwise the sound becomes slightly "glassy" and diffuse. If these points are observed, Devialet's "Master&Companion" is a extensively equipped amp double, which is worth every last cent.
This double mono amplifier does not only feature an interesting concept, but also underlines the technical and sonic maturity and characteristics of Devialet. This test allows only one verdict: Take two!
Price: ca. 9900 € (Last check: 01/08/2020)
Dimensions WxHxD: 39 x 4 x 38 cm
Weight: 11 kg
Warranty: 5 years
|Signal-to-noise ratio related to 24 bits:||115 dB|
|Distortion factor -9dBFS/400Hz:||0.002 %|
|Distortion factor -60dBFS/400Hz:||0.7 %|
|Converter linearity at -90dBFS:||<0.1 dB|
|Continuous power at 8 Ohm (1kHz):||170 W|
|Continuous power at 4 Ohm (1kHz):||336 W|
|Pulse power at 4 Ohm (1kHz):||445 W|
|Distortion factor at 50mW (1kHz):||0.01 %|
|Distortion factor at 5W (1kHz):||0.001 %|
|Distortion factor at Pmax -1dB (1kHz):||0.06 %|
|Intermodulation at 50mW (according to DIN):||0.003 %|
|Intermodulation at 5W (according to DIN):||0.0005 %|
|Intermodulation at Pmax -1dB (according to DIN):||0.0002 %|
|Signal-to-noise ratio from high level input at 50mW (1kHz):||74 dB|
|Signal-to-noise ratio from high level input at 5W (1kHz):||84 dB|
|Signal-to-noise ratio Phono MM (5 mV / 1 k) at 5 Watt:||81 dB(A)|
|Signal-to-noise ratio Phono MC (0.5 mV / 10 Ohm) at 5 Watt:||73 dB(A)|
|Damping factor at 4 Ohm at 63Hz/1kHz/14kHz:||75/70/Schutz|
|Upper cut-off frequency (-3dB/4Ohm):||>80 kHz|
|Crosstalk between 2 high level inputs:||92 dB|
|Synchronization error Volume control at -60dB:||<0.1 dB|
|Stereo channel separation at 10kHz:||75 dB|
|Input level regulator:||nein|
|Power consumption Standby:||19 W|
|Power consumption Idling:||55 W|
|Measured at a mains voltage of:||223 Volt|
Sound Level Integrated amplifier: 97%
High power meets extremely low distortion and very effective channel separation. The other data also underlines the quality of Devialet's unique ADH amplifier concept.
One analog RCA input either for high level devices or MC/MM pickups, one coaxial and two optical digital inputs, USB, Ethernet, high-bit WLAN, "Roon ready", balance and tone control, high flexibility thanks to online configuration, control app for IOS and Android, wireless remote control
Turntable: Thorens TD1601 with Audio-Technica AT-ART9
Media-Player: T+A MP3100HV
Pre-/Power-Amp: Accustic Arts Tube PreampII-MK2/AmpII-MK4
Speaker: B&W 800D3, DALI Epicon 6, Dynaudio Confidence 50
Cable: HMS Suprema (Netz, NF & LS)