Short answer: a tie on measured performance. Both are rated 4.5/5 (#25 and #23 of 30 DACs) at nearly the same price ($84.99 vs $84.99), so choose on features and fit.
Why pick the Fosi Audio Q6: Audio Science Review measured 115 dB SINAD, so its noise and distortion are transparent. The tradeoff: There are no balanced outputs and no volume control, so it needs an amp or speakers with their own volume.
What the SMSL SU-1 does well: Audio Science Review measured a SINAD of 116 dB, so its noise and distortion are inaudible. The tradeoff: It has no volume control of its own, so level must be set on the computer or the downstream amp, and there is no balanced output or Bluetooth.
Buy the Fosi Audio Q6 or the SMSL SU-1 on features: they are rated the same at close to the same price.
Want more options? Browse the full Headphone Amps and DACs rankings.
Specifications Side By Side
| Fosi Audio Q6 | SMSL SU-1 | |
|---|---|---|
| Price | $84.99 | $84.99 |
| Ranked | #25 of 30 in DACs | #23 of 30 in DACs |
| Device Type | DAC | DAC |
| SINAD | 115 dB (measured by Audio Science Review) | 116 dB (measured by Audio Science Review) |
| Balanced Output | No | No |
| Inputs | USB-C, optical, coaxial | USB, optical, coaxial |
| Outputs | RCA, sub out | - |
| DAC Chip | AK4493S | AK4493S |
| Volume Control | None (fixed-level DAC) | None (PC volume) |
| Dimensions | - | 3.8” x 1.1” x 3.1” (96 x 27 x 78 mm) |
| Weight | - | 0.4 lbs (195 g) |
Related Amp and DAC Comparisons
How SMSL SU-1 compares with other leading options:
- SMSL SU-2 vs SMSL SU-1
- SMSL SU-6 vs SMSL SU-1
- SMSL PS200 PRO vs SMSL SU-1
- SMSL SU-1 vs Topping E30 II Lite
- SMSL SU-1 vs Topping D10s
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
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
SMSL SU-1: $84.99 Amazon eBay
Pros: Audio Science Review measured a SINAD of 116 dB, so its noise and distortion are inaudible. It is a compact, inexpensive DAC with USB, optical and coaxial inputs that connects to an amp or powered speakers.
Cons: It has no volume control of its own, so level must be set on the computer or the downstream amp, and there is no balanced output or Bluetooth. The SMSL PS200 PRO measured cleaner at 120 dB for about the same price, and the SMSL SU-2 rates higher for only a little more.
Full SMSL SU-1 review and specifications →
| Released | 2023 (3 years ago) |
|---|---|
| Balanced Output | No |
| DAC Chip | AK4493S |
| Device Type | DAC |
| Dimensions | 3.8” x 1.1” x 3.1” (96 x 27 x 78 mm) |
| Inputs | USB, optical, coaxial |
| SINAD | 116 dB (measured by Audio Science Review) |
| Volume Control | None (PC volume) |
| Weight | 0.4 lbs (195 g) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons