Devialet Expert 250 Pro Integrated Amplifier w/Phono, AirPlay, Roon Ready, 2 x 250W

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General:

Incredibly capable and sleek streamer/amp from France that's carved out of a single block of aluminum.

$19,000 MSRP with Core Infinity which this unit has installed.

Well cared for and working perfectly, the top display is bright and perfect, and updated to the latest available Devialet firmware.

Original Devialet SD Card also installed for custom desired user-configured options (currently set to defaults).

Nickel finish shows some tarnish or fingerprints consistent with any typical use. No scratches or dents however.

Comes to you in its original box with manual and remote. matching finish "Expert" remote jog-style remote control.

(Stock images from the Devialet website to best show off the amp, as it's so reflective it can be difficult to photograph!).

More from Devialet:
All the promises of an Expert Pro system.
A piece of craftmanship for extreme performance.

The Expert 250 Pro pushes the limits of power amplification thanks to an exclusive hand-polished casing, equipped with a 100% pure copper bottom plate.

UPNP, Soon Ready, AIR, AirPlay, Spotify Connect, and More to Come...

Specifications:
Casing
Carved out from a single aluminium block

Range
Stereo

Power
2 x 250 Watts RMS under 6Ω

Distortion at full power
0.0005% THD+N

Distortion at full power
0.00025% (10W / 6Ω)

Distortion at 10w
0.00025% THD+N

Distortion at 10V
0.0005% (250W / 6Ω)

Signal-to-noise ratio
130dB

Output impedance
0.001Ω

Damping factor
8000

Bandwidth
DC-30kHz @ -0.1dB
DC-95kHz @ -3dB

Phase rotation
0.4° at 20kHz
1.8° at 40kHz

Thermal distorsion
Below measurement threshold

Phono stage
Advanced (MM / MC)

Streaming services
Roon Ready
UPnP
Airplay®
Spotify Connect

Exclusive technologies
ADH®, SAM®, RAM®, EVO®, DAC Magic Wire®

Pre-amplified output
Yes (mono / stereo)

wi-fi
2.4GHz / 5GHz 802.11ac, compatible with 802.11a/b/g/n

Ethernet
RJ45 100/1000 Mbps

usb
USB Audio 2.0 Asynchronous
Very low latency
Bi-directionality (for digitisation of the analog sources)

Digital coaxial inputs
Up to 4x RCA 75Ω

Digital optical inputs
1x TOSLINK
Up to 1x miniTOSLINK 3.5mm

Supported formats
Up to 32bits / 192kHz PCM (USB)
Up to 24bits / 192kHz PCM (Roon Ready, UPnP, AES/EBU, Coaxial)
Up to 24bits / 96kHz PCM (Optical)
Up to 1bit / 3.072000MHz DSD64 (USB, Coaxial)

Analog inputs
Up to 2x RCA stereo
Sensitivity adjustable via the Configurator
Advanced phono stage (MM / MC)

Speaker output
4mm banana plugs, fork connectors or stripped cables
Compatible with all speakers from 8Ω to 2Ω
Short-circuit protection
Active filtering available

Home automation
Up to 1x RS232 3.5mm 115200 bauds (documentation available via the Configurator)

Trigger
3.5mm trigger connector Trig In and Trig Out

Power Supply
Universal 90-240Vac – 50/60Hz
Power cable provided adapted to the country
Patented single stage switching mode topology
High power level: 600W continuous, 4000W peak
High output with power factor correction (PFC)

Daisy chaining
Up to 8 units

Dimension
Width: 15.75" (400mm) | Depth: 15.75" (400mm) | Height: 1.57" (40mm)

Weight
21.38 lbs (9.7Kg)

Recommended Cables:

D60 Digital Coaxial Interconnect (RCA/BNC Connectors)

OPT-1 Digital Optical Interconnect (TOSLINK Connectors)

Summit Series Silver Streak Analog Interconnects (PAIR) - RCA Ultraplate or WBT Connectors - Better

Select Series KS1016 Copper RCA Analog Interconnects (Pair) - WBT Connectors - Best 

Kimber Kable - Phono Interconnects - Better

Kimber Kable - Flagship Phono Interconnects - Best

Summit Series Monocle XL Speaker Cables (PAIR) - Better

Summit Series BiFocal XL Bi-Wire Speaker Cables (PAIR) - Best

Base Series PK14 Power Cord (14AWG/Gauge) - Better

Base Series PK10 Power Cord (10AWG/Gauge) - Best 

Testing Process:

We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect the PCBs for discoloration from resistors or transistors that may have been running hot. On vintage units we often spot check select capacitors for value and ESR. 

If the device has the ability to decouple the preamplifier from the power amplifier, we remove the jumpers and independently test each section. If the device cannot be decoupled, we assess the electronic condition of the piece by analyzing the speaker level output only. 

We start by connecting the "Pre-Out" jacks of the integrated to a Sencore PA81 Power Analyzer which simulates real world loading conditions and gives us an oscilloscope interface. The first order of business is checking that the volume control works smoothly throughout its entire range with acceptable channel balance. This is accomplished by feeding a 1 KHz sine wave into one of the preamp’s line level inputs while monitoring the preamp’s output on an oscilloscope.

We then switch to a 1 KHz square wave to test the tone controls, loudness function, and filters where applicable. During this step we are watching for equal alteration of the test signal by both channels. This also helps us identify dirty controls that will need treatment.

Once the basic line stage functions are verified, we test each input individually. This is especially important for devices that use relays to select their sources.

If the preamp section is equipped with a phono stage we test that as well. We use an inverse RIAA filter which allows us to feed a reference test signal into the phono input with the proper RIAA equalization and level. A square wave or sine sweep is used to verify that the device’s phono stage is faithfully reproducing the RIAA curve.

Next we test the power amplifier section by connecting the integrated amplifier speaker outputs to a Sencore PA81 Power Analyzer which acts as a dummy load, DC offset monitor, and oscilloscope interface. We start with a low level 1 KHz test signal at the "Main In” jacks and slowly increase its amplitude while monitoring the output on an oscilloscope for signs of noise, clipping, distortion, or improper channel balance. We continue increasing the signal level until the amplifier reaches clipping.

At this point we take an output power measurement and compare it to the spec sheet of the amplifier to verify proper performance. We finish off the bench evaluation with a 1 KHz square wave check and a 20 Hz to 20 KHz sine sweep to assess the amplifier’s frequency response characteristics. 

This battery of tests will usually reveal if the amplifier has any issues that need further attention. 

If the preamp and power amp both pass these tests, we reconnect the sections and verify that the preamp section can drive the power amp to rated power with a 1KHz tone on one of the line level inputs. 

Before the device leaves the bench, we perform a listening test with actual music using a variety of preferred test tracks. Our benches are outfitted with familiar monitor speakers which help us identify inconsistencies that will not always show up on our test gear. The main things that we are listening for are hum or noise with no signal present, proper center image, clicks, pops, or any other obvious undesirable audio characteristics. 

If the unit passes all of these tests it moves to our long term testing rig where we simulate real word operating conditions for 6-8 hours minimum. This allows us to monitor the unit for signs of thermal runaway or intermittent issues that only crop up when the unit has fully come up to temperature.