SMSL SU-1

General/Build/Packaging
SMSL produces a wide range of sources, ranging from budget to high end. For those who are not familiar with SMSL, the full name of it is Foshan ShuangMuSanLin, a manufacturer of audio DAC and various headphone amps with their own R&D team as well as marketing team. This is my first time testing out SMSL’s product. I have the SU-1 with me today which is a DAC only without the amp section.

Packaging is fairly straightforward, cardboard box containing the DAC itself, and also the USB cable. This tiny little device can be powered solely via USB port, so you don’t need any additional power supply. SU-1’s “Heart”, which is the AK4493S is housed within a CNC aluminium alloy housing, this ensures better heat dissipation as well as durability.

Specifications

• Inputs: USB, optical, coaxial
• Output level: 2.0Vrms
• THD+N: 0.00013%
• Dynamic range: 121dB
• SNR: 121dB
• USB transmission: Asynchronous transmission
• USB compatibility: Windows 7/8/8.1/10/11, Mac OS X10.6 and above, Linux
• Max bit depth and sampling rate: 32bit/768kHz PCM USBM, 22MHz DSD USB, 24bit/192kHz Optical/Coaxial
• MQA: 384kHz
• Power consumption: <5W
• Standby power: <0.1W
• Weight: 0.43lbs
• Size: 3.7" x 1" x 3" (96 x 27 x 78mm)

IEMs/Headphones/Equipments used for this review

• SMSL SU-1 -> EarMen ST-Amp
• SMSL SU-1 -> iFi Zen Can
• Truthear Zero: Red
• Hifiman Edition XS
• Raptgo Bridge

*SU-1 is sent over by ShenzhenAudio for the purpose of this review. I appreciate the opportunity and support given as always.

Foreword
My review is solely based on what I hear via my equipment and I never consider my reviews to be objective in any way rather a subjective approach. Do take into consideration that everyone’s ear anatomy is not the same, so the psychoacoustics perception might be different as well, but i believe it will not stray too far. I have used the Angel for several months prior to writing this review.

Size Comparison


Notable Features

• The SU-1 supports MQA decoding technology, offering high-fidelity in a smaller file size
• The SU-1 uses a third-generation XMOS XU-316 processor for a stable and low-latency USB connection
• It incorporates an AKM AK4493S DAC chip for decoding PCM 32-bit/768kHz and DSD512 formats.
• The housing features an anodized finish with chamfered edges, giving it a premium stealthy look

Sound Impression
To my ears, SU-1 sounds rather neutral with a little bit of AKM’s flavour. Depending on the amp that you are pairing it with, it might sound warm or clinical, i am pairing it with EarMen’s ST-Amp, which is rather uncolored with very good dynamics. Timbre sounds natural to my ears.

• Soundstage is average, slightly out of the head, with average depth and height, imaging on the other hand is good
• Bass is not emphasised, male vocal with low baritone voice sounds a little lacking in terms of texture
• Mids are flat and instruments are well articulated with good textures all around
• Female vocal does have better texture and sounds sweeter
• The treble region is presented in a detailed manner without introducing sibilance
• SU-1 has very good dynamic range and it sounds like it is performing at its best when paired with ST-Amp

Listening Impression with various Headphone/IEM
Hifiman Edition XS

• Bass is presented with good texture, nice and decent sub bass rumble
• Punchy bass with good slams
• Mids are a little forward compared to Earmen Angel’s DAC
• Good imaging based on my HRTF
• Soundstage is good, slightly out of your head while retaining EDXS’s intended tuning
• Sounds a little bit more musical overall to my ears when paired with SU-1

Truthear Zero: Red

• Bass has good texture,sounds a little fuller
• Mids are being brought forward a little bit so Zero: Red doesn’t sound that recessed
• Treble remains smooth while still being a little energetic
• Soundstage doesn’t really change much, imaging is slightly improved to my ears

Raptgo Bridge

• Airy presentation and very 3D-ish soundstage
• Bass punch a little harder with slightly better extension on the treble, bass sounds fuller overall
• Treble has a little bit more extension
• Very good synergy overall

AMP Pairing Note

• Pairing with the iFi Zen Can seems to made the overall presentation slightly warmer while retaining dynamics, it made the music sounds fuller overall, suitable to pair it with Planar headphones and cool sounding IEMs
• Switching the amp to Earmen’s ST-AMP, the sound is very different, in the sense where ST-AMP itself is quite neutral, what it does when paired with SU-1 is that it brings out the dynamics, imaging and separation is very good, technicalities of this pairing is excellent, but in terms of tonality, it is a little on the cool side and slightly lacking in terms of note weight

Final Thoughts
SU-1 is my first DAC only product, i have tested various dac-amps but none of them are purely DAC. SU-1 in my opinion is well built, sounds good when paired with a good amp, depending on your preference, if you like your sound coloured, you may pair it with iFi’s amp, if you are like me, you like the sound uncolored, you may pair it with Topping’s amp or the one that i’m using it with currently, Earmen’s ST-Amp.

For the price and the features that come alongside with SU-1, I think it is a no-brainer and easy recommendation. If SMSL is able to release another model without the MQA rendering, I believe the cost can be brought down a little, with all that being said, i’d still recommend this dac without any doubt!

If you’re interested in getting this unit, head over to ShenzhenAudio’s store and get one now:

SMSL SU-1 DAC - Non affiliated