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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: 27" iMac with 3.4GHz quad-core Intel Core i7, 16GB 1.333MHz RAM, 2TB hard disc, 256GB SSD drive, ADM Radeon HD 6970M with 2GB of GDDR5 memory, PureMusic 1.86 in hybrid memory play with pre-allocated RAM and AIFF files up to 24/192; Audirvana 1.3.9.10 in direct/integer mode, April Music Eximus DP1, Esoteric/APL Hifi UX1/NWO-M w. Bakoon BPS-02 battery-powered Audiophilleo 2, Apple iPod Classic 160GB/AIFF, Cambridge Audio iD100
Preamp/Integrated: ModWright LS-100 with Psvane tubes, Esoteric C-03, Bent Audio Tap-X, TruLife Audio Athena, Bakoon AMP-11R
Amplifier: First Watt SIT1, FirstWatt SIT2, ModWright KWA100SE
Speakers: Aries Cerat Gladius, Boenicke Audio B10, Voxativ Ampeggio
Headphone amp: Bakoon AMP-11R
Headphones: ALO Audio-recabled Audeze LCD2, Sennheiser HD800, Beyerdynamic T1 and T5p, AKG K-702; HifiMan HE500 & HE6
Cables: Complete loom of Zu Audio Event, KingRex uArt USB cable with Bakoon BPS-02
Stands: Artesania Esoteric double-wide 3-tier with TT glass shelf, Rajasthani solid hardwood console for amps
Powerline conditioning: GigaWatt PF2 on amps,GigaWatt PC-3 SE Evo on front-end components
Sundry accessories: Extensive use of Acoustic System Resonators, noise filters and phase inverters
Room size: 5m x 11.5m W x D, 2.6m ceiling with exposed wooden cross beams every 60cm, plaster over brick walls, suspended wood floor with Tatami-type throw rugs. The listening space opens into the second storey via a staircase and the kitchen/dining room are behind the main listening chair. The latter is thus positioned in the middle of this open floor plan without the usual nearby back wall.
Review Component Retail: $599

The Resonessence Labs Concero is $600. As my Peruvian friend Saturnino would say, that's muchissimo less than their $4.000 Invicta yet inherits core circuitry. The secret behind such miniaturization? The ESS Sabre ES9023 with integral 2Vrms driver from a 3.3V supply. It parks all basic necessities on the IC itself. Think one-stop circuit shopping. When such a chip generates the necessary output voltage, a designer of a budget DAC needn't build a complex analog stage. Add a few passive external components to mint a converter. If his fave chip doesn't produce the needed signal strength, he can still go multi parallel until it does. That's CAD's £6.900 1543 DAC. It parallels 16 Philips TDA1543 chips to make 1.65V out. It merely adds passive I/V conversion with one exotic cap and resistor. Metrum's popular Octave and newer Hex do it similarly just with different silicon. Wyred4Sound's tiny $399 µDac [right] goes Sabre and outputs a full 2.5V analog.


Whilst the Concero's Sabre undercuts the industry-standard 2V, it still nets 1.2Vrms* at 300Ω output impedance to put analog conversion inside the box. Given the excessive voltage gain of most systems, that lower output can actually work better and increase overall S/N. The Concero is very attractively encased in a quality monolithic aluminum casing and made in Canada not China. Something more had to give than just drop a 't'. Here that's the power supply. There ain't one. The Concero slurps USB juice. Those into health food can go battery with something trick like a split USB cable à la KingRex uArt or uCraft. Plug their power tail into Bakoon's uninterruptible BPS-02 battery supply at left and feast on pure ultra low-impedance DC 24/7. That's how I run my Audiophilleo 2. Others note 'galvanically isolated' on the Concero's async 24/192 USB input and care not. Its Thesycon driver is de rigueur for Windows but not Mac. With its analog RCA outputs the Concero is obviously a proper converter but that single digital coax can also keep things digital. Then this black box outputs a low-jitter transformer-coupled S/PDIF signal. This would use the Concero as a USB-to-S/PDIF bridge if you mean to handle analog conversion with a DAC you already own but which lacks USB. This turns the Concero into a direct competitor for the Audiophilleo 2, Stello U3, hiFace II & Co.
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* "We did this to allow for a bit more than 4dB of headroom inside the DAC chip itself. This was a preference we had based on listening tests."

But there's more. Connect a standard iDevice-type wall-power adaptor to the Concero. Now it doesn't see music signal on its USB input, just 5V wall power. This automatically converts the digital coax into an input. Presto, the Concero USB DAC is transformed into an S/PDIF DAC. There's more still. By hijacking Apple's stylish mini metal remote with its standard IR code—no pairing required—Resonessence gives you control over basic playlist features plus access to either their custom IIR or apodizing 4x upsampling filter which does 176.4/192kHz to 44.1/48kHz sources respectively. You can even turn off their analog or digital outputs that way. Obviously that's true even if you're a Windows gal or guy. Their online store offers a $650 package with remote and wall power adaptor. For visual confirmation the backlit logo even changes color like Audioquest's tiny Dragonfly does (here blue is for native mode, magenta for integer upsampling).


To condense for essentials, the Concero is from the same team which originally designed the ESS Sabre chip. It works as a compact USB bridge, USB DAC or S/PDIF DAC and incorporates trickle-down tech from their well-regarded full-featured $4.000 statement converter by stripping away features. Then it sells for just 15% of that IQ provider. On paper this model would seem to pack quite the knockout punch.