Short answer: the SMSL D-6S. It ranks #9 of 30 DACs by measured performance, rated 4.8/5, at $199.99. The SMSL SU-6 ranks #20, rated 4.6/5, at $169.99, $30 cheaper, not enough of a saving to outweigh the sound-quality gap.
What the SMSL D-6S does well: Audio Science Review measured 122 dB SINAD, so its noise and distortion are transparent. The catch: There is no volume control listed, so it relies on the amp or speakers downstream to set level.
Why pick the SMSL SU-6: Audio Science Review measured a SINAD of 118 dB, so its noise and distortion are inaudible. The tradeoff: It has only RCA outputs, with no balanced XLR.
Buy the SMSL D-6S. It is rated higher, and saving $30 with the SMSL SU-6 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 D-6S | SMSL SU-6 | |
|---|---|---|
| Price | $199.99 | $169.99 |
| Ranked | #9 of 30 in DACs | #20 of 30 in DACs |
| Device Type | DAC | DAC |
| SINAD | 122 dB (measured by Audio Science Review) | 118 dB (measured by Audio Science Review) |
| Balanced Output | Yes (XLR line out) | No |
| Inputs | USB, optical, coaxial, Bluetooth | USB, optical, coaxial, Bluetooth |
| Outputs | RCA, XLR | RCA |
| Bluetooth Codecs | SBC, AAC, aptX, aptX HD, LDAC | SBC, AAC, aptX, aptX HD, LDAC |
| DAC Chip | ES9039Q2M | ES9038Q2M |
| Dimensions | 5.9” x 1.7” x 5.1” (150 x 42 x 128.5 mm) | 5.5” x 1.1” x 4.1” (140 x 28 x 105 mm) |
| Weight | 1.6 lbs (710 g) | 0.8 lbs (350 g) |
Related Amp and DAC Comparisons
How SMSL D-6S compares with other leading options:
- Topping D50 III vs SMSL D-6S
- SMSL D-6S vs SMSL DO200 MKII
- Fosi Audio ZD3 vs SMSL D-6S
- SMSL D-6S vs SMSL D200
- SMSL D-6S 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 D-6S: $199.99 Amazon eBay
Pros: Audio Science Review measured 122 dB SINAD, so its noise and distortion are transparent. It offers USB, optical, coaxial and LDAC Bluetooth inputs with RCA and XLR outputs for an amp or powered speakers. It matches the rating of the Topping D70 Pro SABRE for far less.
Cons: There is no volume control listed, so it relies on the amp or speakers downstream to set level. DACs such as the Topping D70 Pro SABRE measure a touch cleaner at 123 dB, though they cost far more and the difference is not audible.
Full SMSL D-6S review and specifications →
| Released | Sep 2023 (3 years ago) |
|---|---|
| Balanced Output | Yes (XLR line out) |
| Bluetooth Codecs | SBC, AAC, aptX, aptX HD, LDAC |
| DAC Chip | ES9039Q2M |
| Device Type | DAC |
| Dimensions | 5.9” x 1.7” x 5.1” (150 x 42 x 128.5 mm) |
| Inputs | USB, optical, coaxial, Bluetooth |
| Outputs | RCA, XLR |
| SINAD | 122 dB (measured by Audio Science Review) |
| Weight | 1.6 lbs (710 g) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
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