Short answer: the Fosi Audio ZD3 for better measured performance, the SMSL SU-2 for the lower price. The Fosi Audio ZD3 ranks #15 of 30 DACs, rated 4.8/5, at $179.99. The SMSL SU-2 ranks #18, rated 4.7/5, at $99.99, $80 cheaper.
What the Fosi Audio ZD3 does well: Audio Science Review measured 117 dB SINAD, so its noise and distortion are transparent. Watch for: Its SINAD is a few dB behind similarly rated DACs like the SMSL D-6S, though both are transparent.
What the SMSL SU-2 does well: Audio Science Review measured 123 dB SINAD, so its noise and distortion are transparent. The tradeoff: There is no USB input listed, so a computer needs a separate USB to digital converter.
Buy the Fosi Audio ZD3 if measured performance is the priority over the price, or the SMSL SU-2 if the price is the priority over measured performance.
Still deciding? The full Headphone Amps and DACs rankings cover every ranked option.
Specifications Side By Side
| Fosi Audio ZD3 | SMSL SU-2 | |
|---|---|---|
| Price | $179.99 | $99.99 |
| Ranked | #15 of 30 in DACs | #18 of 30 in DACs |
| Device Type | DAC | DAC |
| SINAD | 117 dB (measured by Audio Science Review) | 123 dB (measured by Audio Science Review) |
| Balanced Output | Yes (XLR line out) | Yes (XLR line out) |
| Inputs | USB, HDMI ARC, optical, coaxial, Bluetooth | AES/EBU, optical, coaxial |
| Outputs | RCA, XLR | RCA, XLR |
| Bluetooth Codecs | SBC, AAC, aptX, aptX HD | - |
| DAC Chip | ES9039Q2M | ES9039Q2M |
| Volume Control | Digital preamp (remote) | - |
| Dimensions | - | 5.9” x 1.7” x 5.2” (150 x 42.5 x 133.1 mm) |
| Weight | - | 1.2 lbs (533 g) |
Related Amp and DAC Comparisons
More worthwhile head-to-heads for Fosi Audio ZD3:
- Topping D50 III vs Fosi Audio ZD3
- Fosi Audio ZD3 vs SMSL D-6S
- Fosi Audio ZD3 vs SMSL D200
- Fosi Audio ZD3 vs SMSL SU-6
- Fosi Audio ZD3 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
Fosi Audio ZD3: $179.99 Amazon eBay
Pros: Audio Science Review measured 117 dB SINAD, so its noise and distortion are transparent. It has unusually broad connectivity, with USB, HDMI ARC from a TV, optical, coaxial and aptX HD Bluetooth inputs, plus RCA and XLR outputs and a remote controlled digital preamp for driving powered speakers directly. It matches the rating of the SMSL D-6S for a bit less.
Cons: Its SINAD is a few dB behind similarly rated DACs like the SMSL D-6S, though both are transparent. Bluetooth lacks LDAC, which the SMSL D-6S includes.
Full Fosi Audio ZD3 review and specifications →
| Released | Sep 2024 (2 years ago) |
|---|---|
| Balanced Output | Yes (XLR line out) |
| Bluetooth Codecs | SBC, AAC, aptX, aptX HD |
| DAC Chip | ES9039Q2M |
| Device Type | DAC |
| Inputs | USB, HDMI ARC, optical, coaxial, Bluetooth |
| Outputs | RCA, XLR |
| SINAD | 117 dB (measured by Audio Science Review) |
| Volume Control | Digital preamp (remote) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
SMSL SU-2: $99.99 Amazon eBay
Pros: Audio Science Review measured 123 dB SINAD, so its noise and distortion are transparent. It sends RCA and XLR outputs to an amp or powered speakers, and accepts AES/EBU, optical and coaxial digital sources. It matches the rating of the Topping Centaurus and measures cleaner for a small fraction of the price.
Cons: There is no USB input listed, so a computer needs a separate USB to digital converter. It has no Bluetooth or volume control, and the SMSL D-6S rates higher with USB and LDAC Bluetooth for more money.
Full SMSL SU-2 review and specifications →
| Released | Jan 2026 (9 months ago) |
|---|---|
| Balanced Output | Yes (XLR line out) |
| DAC Chip | ES9039Q2M |
| Device Type | DAC |
| Dimensions | 5.9” x 1.7” x 5.2” (150 x 42.5 x 133.1 mm) |
| Inputs | AES/EBU, optical, coaxial |
| Outputs | RCA, XLR |
| SINAD | 123 dB (measured by Audio Science Review) |
| Weight | 1.2 lbs (533 g) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons