s.m.s.l SU-1

Tharbamar calls the sound engaging, natural, organic, refined, and free of listening fatigue, saying it avoids making digital music feel overtly digital. Audio Masterclass similarly hears weight and a full-bodied tone, while Cheap Audio Man finds it dynamic and clean without harshness, grain, or a chalky edge. There are small tonal reservations: Cheap Audio Man finds the bass less fully fleshed out than a comparator, and Tharbamar notes a slight, non-problematic treble roll-off.

Tharbamar reports clear vocals, audible low-level conversation, and micro-detail comparable with considerably more expensive DACs. Cheap Audio Man also hears more air and more activity in the upper range, while the strong center image and added depth described by Tharbamar support a well-separated presentation. The review evidence is enthusiastic, although detailed comparisons across a wide range of reference DACs are limited.

The SU-1 is repeatedly described as clean, quiet, and free from grain, glare, or obvious digital hardness; Tharbamar says it can sound so natural that it does not call attention to digital playback. Optical input is reported to have no switching-noise issue and a very low background-noise level for the price, while coaxial is said to improve refinement and noise control further. USB has the main caveat: faint noise can occur during format changes and occasionally in playback.

The compact chassis uses CNC aluminium-alloy housing, and Cheap Audio Man and Audio Masterclass both describe a convincing look and feel. Audio Masterclass considers it impressively well made despite its tiny size. Reviewers say little about internal construction, power-supply design, or long-term durability.

The SU-1 provides USB-C, optical, and coaxial digital inputs, plus a pair of RCA outputs; USB also supplies power. It supports PCM up to 32-bit/768kHz, DSD512, and MQA, covering virtually all common high-resolution playback formats. It remains a compact, fixed-output DAC without balanced outputs, a headphone amplifier, network playback, or an elaborate front-panel interface.

At roughly $72–$80, reviewers portray the SU-1 as an exceptional buy rather than merely a competent budget option. Cheap Audio Man calls it the best-sounding affordable DAC he has heard below $100 and recommends it without meaningful concessions, while Tharbamar calls it rare at the price and says buyers will not regret spending $80.