Short answer: the SMSL SU-6 on measured measured performance, the Fosi Audio Q6 on price. The SMSL SU-6 ranks #20 of 30 DACs, rated 4.6/5, at $169.99. The Fosi Audio Q6 ranks #25, rated 4.5/5, at $84.99, $85 cheaper.
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.
The case for the Fosi Audio Q6: Audio Science Review measured 115 dB SINAD, so its noise and distortion are transparent. Watch for: There are no balanced outputs and no volume control, so it needs an amp or speakers with their own volume.
Buy the SMSL SU-6 if measured performance matters more than the price. Buy the Fosi Audio Q6 if the price matters more than measured performance.
Want more options? Browse the full Headphone Amps and DACs rankings.
Specifications Side By Side
| SMSL SU-6 | Fosi Audio Q6 | |
|---|---|---|
| Price | $169.99 | $84.99 |
| Ranked | #20 of 30 in DACs | #25 of 30 in DACs |
| Device Type | DAC | DAC |
| SINAD | 118 dB (measured by Audio Science Review) | 115 dB (measured by Audio Science Review) |
| Balanced Output | No | No |
| Inputs | USB, optical, coaxial, Bluetooth | USB-C, optical, coaxial |
| Outputs | RCA | RCA, sub out |
| Bluetooth Codecs | SBC, AAC, aptX, aptX HD, LDAC | - |
| DAC Chip | ES9038Q2M | AK4493S |
| Dimensions | 5.5” x 1.1” x 4.1” (140 x 28 x 105 mm) | - |
| Weight | 0.8 lbs (350 g) | - |
| Volume Control | - | None (fixed-level DAC) |
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
Fosi Audio Q6: $84.99 Amazon eBay
Pros: Audio Science Review measured 115 dB SINAD, so its noise and distortion are transparent. It takes USB-C, optical and coaxial inputs and feeds an amp or powered speakers over RCA, with a separate sub out for adding a subwoofer. It matches the rating of the SMSL PS200 PRO for slightly less.
Cons: There are no balanced outputs and no volume control, so it needs an amp or speakers with their own volume. The SMSL SU-2 rates higher with lower measured distortion and XLR outputs for a little more.
Full Fosi Audio Q6 review and specifications →
| Released | Apr 2025 (1 year ago) |
|---|---|
| Balanced Output | No |
| DAC Chip | AK4493S |
| Device Type | DAC |
| Inputs | USB-C, optical, coaxial |
| Outputs | RCA, sub out |
| SINAD | 115 dB (measured by Audio Science Review) |
| Volume Control | None (fixed-level DAC) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons