85%
s.m.s.l SU-X
ES9039MS PRO ×2
Support MQA decoding and MQA-CD;
The brand-new third-generation XMOS XU-316, PCM supports to 32bit/768kHz, and DSD supports to DSD512;
Two groups of linear power supplies are used to supply power to digital and analog units respectively. With multiple low-noise regulated power supplies, provide a stable, reliable, efficient, and low-noise power supply system for SU-X.
Using dual latest flagship DAC chip ES9039MSPRO from American ESS, built-in MQA decoding;
Using eight-channel parallel circuit design, the distortion is as low as 0.00004%(-128dB), ensuring more stable.
Use 21 high-end dual op-amps and a large number of HiFi components;
Adopting 2nd PLL to eliminate SPDIF transmission JITTER;
Brand-new self-developed CK-03 clock processing circuit greatly reduces clock jitter;
Support DOP independent display, clearly see the current decoding format;
USB, optical, coaxial, AES and I2S support DSD, while coaxial, optical and AES support DOP64.
Use tempered glass to fully fit the color IPS display screen;
Built-in low noise power supply processing, improve power efficiency, and lower power consumption;
With multiple low-noise regulated power supplies, making sure a stable, reliable, efficient and low-noise power supply system.
Qualcomm's high-end Bluetooth chip, supports LDAC(24bit/96kHz),APTX/HD, SBC, AAC;
High-quality all-aluminum shell;
High-quality gold-plated input and output terminals;
Japan Audio Association (JAS)Hi-Res certification;
Equipped with remote control and full-function remote control.
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Professional Reviews 85/100
Nicely Roasted
Sound Quality
82/100
Build Quality
87/100
Features Connectivity
88/100
Value for Money
89/100
The s.m.s.l SU-X brings high-resolution detail, expansive connectivity and flexible preamp operation to a serious digital front end. Soundnews rates its value, resolution and frequency response highly, while its dual-mono architecture, balanced outputs and broad hi-res support make it a compelling hub for listeners chasing an explicit, feature-rich presentation.
What Reviewers Are Saying
Pros
Strong reported resolution, frequency response and value, with Soundnews scoring each area 93/100 or higher.
Comprehensive connectivity includes USB-B, USB-C, optical, coaxial, AES/EBU and I2S inputs, plus balanced and single-ended outputs.
Variable or fixed output operation allows it to serve as a DAC or preamp, and the construction was described as very well executed.
&
Cons
One reviewer found the midrange through lower treble overly energetic and fatiguing, making the tonal balance potentially unsuitable for bright systems or treble-sensitive listeners.
The included remote was considered underwhelming for a $1,000 component.
SOUND QUALITY PERFORMANCE 82/100
The published impressions are sharply divided. Soundnews calls the SU-X a “Breath of Fresh Air” with exceptional sound quality and strong resolution, while Old Guy Hifi found its upper-midrange and lower-treble balance strident, glaring, and difficult to enjoy.
Tonal Balance and Musicality
78/100
Old Guy Hifi reports a consistently fatiguing tonal balance, citing excessive energy through the midrange, upper midrange, and lower treble. That criticism conflicts with Soundnews’s broadly enthusiastic verdict, but the specific glare and listenability concerns are significant.
Resolution and Detail
90/100
Soundnews rates resolution at 93/100 and describes the SU-X’s overall sound as exceptional. No review disputes its ability to retrieve information, although the available commentary does not elaborate on low-level detail or separation.
Digital Performance
79/100
The SU-X supports PCM up to 32-bit/768kHz and DSD512, and Old Guy Hifi notes its reclocked S/PDIF implementation is intended to address jitter and timing. However, that reviewer also hears pronounced glare and hardness, preventing the digital presentation from feeling consistently smooth or natural.
Assessments of Build Quality, Usability, and Overall Propositions.
Build Quality
87/100
Soundnews rates build quality at 87/100, while Old Guy Hifi calls the SU-X very well constructed. The available reviews are positive about construction, though they offer limited detail on internal layout, power supply design, or long-term durability.
Features Connectivity
88/100
The SU-X is comprehensively equipped with USB-B and USB-C, optical, coaxial, AES/EBU, and I2S digital inputs, plus Bluetooth capability. Balanced XLR and single-ended RCA outputs are provided, along with fixed or variable output operation for use as a preamplifier; PCM 32-bit/768kHz and DSD512 support further strengthen its flexibility.
Value for Money
89/100
At $999, Soundnews gives the SU-X a 93/100 value rating, indicating that its performance and specification set compare well in its market segment. Old Guy Hifi is more reserved, characterizing it as something to try only if a buyer is comfortable “rolling the dice” at $1,000 because of the reviewer’s strong tonal objections.
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Authorized dealers for s.m.s.l SU-X
- Addicted to Audio — online and in-store — Epping, Victoria, Australia (website)
- Apos Audio — online and in-store — Oakland, California, United States (website)
- Audio 46 — online and in-store — New York, New York, United States (website)
- Audio Hum — in-store — Norte Sierra, Andalucía, Spain (website)
- Audio Magic - EU — online and in-store — Wola, Województwo mazowieckie, Poland (website)
- AUDIOPHONICS — in-store — Bordeaux, Nouvelle-Aquitaine, France (website)
- Bloom Audio — online and in-store — Gibbsboro, New Jersey, United States (website)
- Elise Audio — online and in-store — Paddington, England, United Kingdom (website)
- Headphone Zone — online and in-store — Laxmi Industrial Estate, Maharashtra, India (website)
- Hifi Passion — in-store — Neustadt, Bremen, Germany (website)
and 4 more verified dealers