Short answer: the xDuoo XA-10. It ranks #35 of 43 DAC and headphone amp combos by measured performance, rated 3.6/5, at $479. The Pro-Ject Pre Box S2 Digital ranks #38, rated 2.9/5, at $399, $80 cheaper, which does not close the gap in measured performance.
The xDuoo XA-10 is the better-sounding choice. It is a very flexible DAC and amp with USB, optical, coaxial and Bluetooth inputs, and Bluetooth supports SBC, AAC, aptX, aptX LL, aptX HD and LDAC. The tradeoff: Audio Science Review measured a SINAD of 90 dB, which is fine for most headphones but may reveal hiss or noise with sensitive in-ear monitors.
What the Pro-Ject Pre Box S2 Digital does well: It accepts USB, optical and coaxial inputs and also works as a preamp with a variable RCA output, all in a compact box about the size of a paperback. The catch: Pro-Ject rates it at only 68 mW into 32 ohms, which suits in-ear monitors and easy headphones but not demanding full-size models.
Buy the xDuoo XA-10. It is rated higher, and saving $80 with the Pro-Ject Pre Box S2 Digital does not make up for the sound-quality gap.
Looking for alternatives? See the complete Headphone Amps and DACs rankings.
Specifications Side By Side
| xDuoo XA-10 | Pro-Ject Pre Box S2 Digital | |
|---|---|---|
| Price | $479.00 | $399.00 |
| Ranked | #35 of 43 in DAC and Headphone Amp Combos | #38 of 43 in DAC and Headphone Amp Combos |
| Device Type | DAC and headphone amp | DAC and headphone amp |
| SINAD | 90 dB (measured by Audio Science Review) | 100 dB (measured by Audio Science Review) |
| Output Power (32 ohms) | 4,000 mW (manufacturer rated, balanced) | 68 mW (manufacturer rated) |
| Headphone Outputs | 6.35 mm, 4.4 mm balanced, 4-pin XLR balanced | 6.35 mm |
| Balanced Output | Yes (4.4 mm, 4-pin XLR) | No |
| Inputs | USB, optical, coaxial, Bluetooth | USB-B, optical, coaxial |
| Bluetooth Codecs | SBC, AAC, aptX, aptX LL, aptX HD, LDAC | - |
| DAC Chip | 2 x AK4493 | 2 x ES9038Q2M |
| Volume Control | Digital (100 steps) | Hardware knob |
| Dimensions | 8.7” x 2.8” x 3.9” (220 x 70 x 100 mm) | 4.1” x 1.5” x 4.8” (103 x 37 x 122 mm) |
| Weight | 2 lbs (900 g) | 0.8 lbs (366 g) |
| Outputs | - | RCA (variable) |
Related Amp and DAC Comparisons
How xDuoo XA-10 compares with other leading options:
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- xDuoo XA-10 vs Essence HDACC II-4K
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
xDuoo XA-10: $479.00 Amazon eBay
Pros: It is a very flexible DAC and amp with USB, optical, coaxial and Bluetooth inputs, and Bluetooth supports SBC, AAC, aptX, aptX LL, aptX HD and LDAC. A rated 4,000 mW into 32 ohms from the balanced outputs drives nearly any headphone, and it offers 6.35 mm, 4.4 mm and 4-pin XLR headphone jacks.
Cons: Audio Science Review measured a SINAD of 90 dB, which is fine for most headphones but may reveal hiss or noise with sensitive in-ear monitors. The Loxjie D40 rates higher and measures far cleaner for less. The rated power figure applies to the balanced outputs, so the 6.35 mm jack delivers less.
Full xDuoo XA-10 review and specifications →
| Released | 2021 (5 years ago) |
|---|---|
| Balanced Output | Yes (4.4 mm, 4-pin XLR) |
| Bluetooth Codecs | SBC, AAC, aptX, aptX LL, aptX HD, LDAC |
| DAC Chip | 2 x AK4493 |
| Device Type | DAC and headphone amp |
| Dimensions | 8.7” x 2.8” x 3.9” (220 x 70 x 100 mm) |
| Headphone Outputs | 6.35 mm, 4.4 mm balanced, 4-pin XLR balanced |
| Inputs | USB, optical, coaxial, Bluetooth |
| Output Power (32 ohms) | 4,000 mW (manufacturer rated, balanced) |
| SINAD | 90 dB (measured by Audio Science Review) |
| Volume Control | Digital (100 steps) |
| Weight | 2 lbs (900 g) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
Pro-Ject Pre Box S2 Digital: $399.00 Amazon eBay
Pros: It accepts USB, optical and coaxial inputs and also works as a preamp with a variable RCA output, all in a compact box about the size of a paperback. Audio Science Review measured a SINAD of 100 dB, which is fine for most headphones.
Cons: Pro-Ject rates it at only 68 mW into 32 ohms, which suits in-ear monitors and easy headphones but not demanding full-size models. At 100 dB SINAD, sensitive in-ears may reveal some hiss, it has no balanced outputs, and the Neutron HiFi DAC V1 rates higher and measured cleaner for less.
Full Pro-Ject Pre Box S2 Digital review and specifications →
| Released | 2017 (9 years ago) |
|---|---|
| Balanced Output | No |
| DAC Chip | 2 x ES9038Q2M |
| Device Type | DAC and headphone amp |
| Dimensions | 4.1” x 1.5” x 4.8” (103 x 37 x 122 mm) |
| Headphone Outputs | 6.35 mm |
| Inputs | USB-B, optical, coaxial |
| Output Power (32 ohms) | 68 mW (manufacturer rated) |
| Outputs | RCA (variable) |
| SINAD | 100 dB (measured by Audio Science Review) |
| Volume Control | Hardware knob |
| Weight | 0.8 lbs (366 g) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons