The S.M.S.L. SU-8 DAC is a transparent-sounding and versatile source component at the centre of your living room system.

In terms of technology, DACs come in many flavors, many of which have the potential to ‘flavor’ the sound being transported from your source. Call me bland, but I prefer the taste of my DACs to be as transparent as possible. It’s the same reason why I prefer a bouillon over a borscht, a neat whisky over a Sherley Temple, and a margarita pizza over a Hawaiian one.

Enter the Delta-Sigma DAC. While not as exotic as R2R and other multibit DACs, Delta-Sigma DACs based on chip makers such as AK and ESS offer transparent and dynamic digital-to-analog conversion, and often at a very digestible price. Chi-Fi staple S.M.S.L. is one such company that is offering well-priced Delta-Sigma DACs. Based on ESS Techology’s ES9038Q2M, let’s see if the SU-8 is worth adding to your budget high-fidelity system.

Specifications

• Input: USB, optical, coaxial

• Output: RCA, XLR

• Output level: 2 Vrms (RCA), 4 Vrms (XLR)

• THD + N: 0.0003%

• Dynamic range: 120 dB

• SNR: 116 dB

• USB compatibility: Windows 7 / 8 / 8.1 / 10, Mac OS X 10.6 or later, Linux

• USB bit depth: 1 bit–32 bit

• Optical/coaxial bit depth: 1 bit–24 bit

• USB sampling rate: PCM: 44.1–768 kHz; DSD: 2.28224–22.5792 MHz

• Optical/coaxial sampling rate: 32–192 kHz, DSD64 (DoP)

• Consumption power: 3W

• Standby power: < 0.1W

• Dimensions, W x H x D: 7.3 x 1.6 x 4.9 in (185 x 40 x 125 mm) Weight: 2.2 lbs (1 kg)

Available in satin-finished silver, the SU-8 comes in an unassuming rectangular, what feels to be aluminum box, accented by radius-ed corners and chamfered edges, so reminiscent of typical i-devices and other, contemporary electronics. While it doesn’t make any loud splashes in terms of design language, it should unassumingly fit into any system composition, unless you subscribe to the Batcave aesthetic of high fidelity audio/video equipment. Sorry living room vigilantes, it does not come in black. Curiously, the underside of the SU-8 curiously has only 3 feet, though its low centre of gravity affords a stable stance.

Besides the i/o connectivity on the back of the device, most other panels on the SU-8 are uninterrupted planes, except for the small, front window situated on the front panel. This window offers a place to house the IR sensor for the remote control (more on this later), as well as a charming, white LED readout that offers an information readout, configurable to display sample rate of the digital audio source its converting to analog signal, or the volume level. It can be dimmed or made to automatically turn off, depending on user preference. The power supply is internal to the device, so no power brick here.

Setting up the SU-8 at the Chi-Fi Review testing station was easy enough, and we had it being fed by a Windows 10 laptop connected via USB. To test additional digital outputs, we connected a Hiby R3 digital audio player via USB C to the coaxial input of the SU-8. Analog output was facilitated via dual 3-pin XLR connectors to a Massdrop THX AAA 789, with RCA outputs connected to a pair of Edifier R1280DB powered speakers.

After a bit of fiddling to get the SU-8 to recognize its remote control (you need to press the button labelled ‘C’ on the remote), we were impressed with the intuitiveness to switch between the various connected inputs and outputs. Volume control via the remote was especially useful, and being able to control both the speaker output, as well as the volume to the headphone amplifier allowed for some convenience, once all of the devices connected volume levels were calibrated appropriately.

The SU-8 has a decent amount of inputs and outputs. Connect sources such as computers, blue-ray players and CD transports via coax, optical and USB. Use the XLR and RCA outputs to connect to anything from powered speakers to monoblock amplifiers.

As always, for objective measurements no one does it better than Audio Science Review. For our review, we will share some of the impressions we had as we used the SU-8 over the course of several months.

In terms of sound, we found the SU-8 to be very transparent, offering a clean signal that was both dynamic and revealing when paired with our test equipment. Tested in a verity of use cases, musical listening via the Edifier R1280DB was enjoyable, and we found that there was no bias to any of the frequency ranges. There was also no discernible clipping or distortion when driving the Beyerdynamic T1 v2 to ear-bleeding levels on the Massdrop THX AAA 789. In both instances, the SU-8 provided clean and transparent signal.

Treble was not sibilant and controlled very well. Mids we clean and balanced, and bass was authoritative and impactful. In all honesty, we are not really sure how much the SU-8 contributed to the overall sound, other than providing a clean and uncolored signal to the rest of equipment in the audio chain.

From a usability performance perspective, having a remote control and access to the various input sources and output channels was a pleasure to utilize. While maybe mundane for some, we enjoyed the simple pleasure of being able to use the SU-8 from the comfort of our couch. Switching sources was a breeze, and the ability to play with some of the DACs in-built features, while novel, made almost no identifiable impact on the overall listening experience.

The SU-8 offers a one-stop shop of inputs and outputs, making it a good reference DAC for anyone building their own audio test bench, listening station or entertainment system.

We at Chi-Fi Review have always believed that a DAC should have no apparent impact on the overall listening experience. A good DAC should disappear, in order to make way for the characteristics of your amplifier (tube, solid state) and output gear (speakers, headphones) to shine. The SU-8 does a good job of getting out of the way, while laying down a solid foundation of a clean and transparent signal.

Besides the SU-8’s transparent performance, we appreciated the utility, connectivity, and functionality it afforded. Its support for a whole slew of use cases such as computer listening via its USB input, as well as alternative home entertainment system compatibility by way of its coax and optical connectivity, makes it a versatile tool for most any situations. It supports all manner of formats including everything up to DSD512, sports single-ended and balanced outputs, and adds remote control functionality, which we appreciated very much.

If there is a single negative caveat to note, is that finding appropriate windows driver was difficult, as S.M.S.L.’s website driver page seemed to be down at the time of writing. However if you are using the SU-8 in OSX, or with optical/coax, there shouldn’t be any issues.

And finally, there’s the price. Brand new you’re looking at paying around $250 USD at the time of writing, and even less if you hunt for various sales on Aliexpress or Drop. For the performance and functionality it offers, it’s hard to beat.

Overall we can wholeheartedly recommend the S.M.S.L. SU-8 for those on a reasonable budget, who want a fully functional and versatile DAC to act as the foundation of a home entertainment system or listening station. It’s a no-fuss and remote-controllable DAC that does what we believe a good DAC should do - that is to say disappear, so that you can get on with enjoying the music.