Short answer: the SMSL SU-6. It ranks #20 of 30 DACs by measured performance, rated 4.6/5, at $169.99; the Sonnect SoundWire ranks #30, rated 2.4/5, at $165. With prices this close, go by the sound-quality ranking rather than the cost.
The SMSL SU-6 is the better-sounding option. Audio Science Review measured a SINAD of 118 dB, so its noise and distortion are inaudible. Watch for: It has only RCA outputs, with no balanced XLR.
Why pick the Sonnect SoundWire: It turns a USB-C phone or computer into a source with two transformer isolated XLR line outputs, which suits connecting directly to powered speakers, mixers or PA systems. Watch for: Audio Science Review measured a SINAD of 85 dB, a level of noise and distortion that is an audible weakness.
Buy the SMSL SU-6. It is rated higher, and saving $4.99 with the Sonnect SoundWire does not make up for the sound-quality gap.
Want more options? Browse the full Headphone Amps and DACs rankings.
Specifications Side By Side
| SMSL SU-6 | Sonnect SoundWire | |
|---|---|---|
| Price | $169.99 | $165.00 |
| Ranked | #20 of 30 in DACs | #30 of 30 in DACs |
| Device Type | DAC | DAC |
| SINAD | 118 dB (measured by Audio Science Review) | 85 dB (measured by Audio Science Review) |
| Balanced Output | No | Yes (XLR line out) |
| Inputs | USB, optical, coaxial, Bluetooth | USB-C |
| Outputs | RCA | 2 x XLR (transformer-isolated) |
| Bluetooth Codecs | SBC, AAC, aptX, aptX HD, LDAC | - |
| DAC Chip | ES9038Q2M | - |
| Dimensions | 5.5” x 1.1” x 4.1” (140 x 28 x 105 mm) | - |
| Weight | 0.8 lbs (350 g) | 0.3 lbs (140 g) |
| Volume Control | - | None (phone/PC volume) |
Related Amp and DAC Comparisons
More worthwhile head-to-heads for SMSL SU-6:
- Topping D50 III vs SMSL SU-6
- SMSL D-6S vs SMSL SU-6
- Fosi Audio ZD3 vs SMSL SU-6
- SMSL SU-2 vs SMSL SU-6
- SMSL SU-6 vs Soncoz LA-QXD1
Prices on this page were last checked October 11, 2026 at 4:59 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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The Two Amps and DACs In Full
SMSL SU-6: $169.99 Amazon eBay
Pros: Audio Science Review measured a SINAD of 118 dB, so its noise and distortion are inaudible. It accepts USB, optical, coaxial and Bluetooth with LDAC, aptX HD and AAC, which makes it a flexible source for powered speakers or a separate amp. It is compact at 140 x 105 mm and 350 g.
Cons: It has only RCA outputs, with no balanced XLR. The SMSL SU-2 rates higher and measures cleaner at 123 dB for less. No volume control is listed, so it relies on the connected amp or speakers.
Full SMSL SU-6 review and specifications →
| Released | Nov 2021 (4 years ago) |
|---|---|
| Balanced Output | No |
| Bluetooth Codecs | SBC, AAC, aptX, aptX HD, LDAC |
| DAC Chip | ES9038Q2M |
| Device Type | DAC |
| Dimensions | 5.5” x 1.1” x 4.1” (140 x 28 x 105 mm) |
| Inputs | USB, optical, coaxial, Bluetooth |
| Outputs | RCA |
| SINAD | 118 dB (measured by Audio Science Review) |
| Weight | 0.8 lbs (350 g) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
Sonnect SoundWire: $165.00 Sonnect eBay
Pros: It turns a USB-C phone or computer into a source with two transformer isolated XLR line outputs, which suits connecting directly to powered speakers, mixers or PA systems.
Cons: Audio Science Review measured a SINAD of 85 dB, a level of noise and distortion that is an audible weakness. It has no headphone output and no volume control of its own. The Samsung USB-C to 3.5mm Headphone Jack Adapter measures cleaner and rates higher for far less, although it lacks XLR outputs.
Full Sonnect SoundWire review and specifications →
| Balanced Output | Yes (XLR line out) |
|---|---|
| Device Type | DAC |
| Inputs | USB-C |
| Outputs | 2 x XLR (transformer-isolated) |
| SINAD | 85 dB (measured by Audio Science Review) |
| Volume Control | None (phone/PC volume) |
| Weight | 0.3 lbs (140 g) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons