Short answer: the Chord Mojo 2. It ranks #21 of 43 DAC and headphone amp combos by measured performance, rated 4.3/5, at $566.86. The Pro-Ject Pre Box S2 Digital ranks #38, rated 2.9/5, at $399, $167.86 cheaper, which does not close the gap in measured performance.
The Chord Mojo 2 is the better-sounding option. Audio Science Review measured a SINAD of 110 dB, which is clean for nearly all listening. The catch: It costs far more than the TRN Black Pearl, which rates higher and measured cleaner at 117 dB.
Why pick the Pro-Ject Pre Box S2 Digital: 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 Chord Mojo 2. It is rated higher, and the $167.86 you would save on the Pro-Ject Pre Box S2 Digital does not close the gap.
Looking for alternatives? See the complete Headphone Amps and DACs rankings.
Specifications Side By Side
| Chord Mojo 2 | Pro-Ject Pre Box S2 Digital | |
|---|---|---|
| Price | $566.86 | $399.00 |
| Ranked | #21 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 | 110 dB (measured by Audio Science Review) | 100 dB (measured by Audio Science Review) |
| Output Power (32 ohms) | 600 mW into 30 ohms (manufacturer rated) | 68 mW (manufacturer rated) |
| Output Power (300 ohms) | 90 mW (manufacturer rated) | - |
| Headphone Outputs | 3.5 mm, 4.4 mm | 6.35 mm |
| Inputs | USB-C, Micro-USB, optical, coaxial | USB-B, optical, coaxial |
| Equalizer | Yes (UHD DSP tone control) | - |
| Dimensions | 3.3” x 2.4” x 0.9” (83 x 62 x 22.9 mm) | 4.1” x 1.5” x 4.8” (103 x 37 x 122 mm) |
| Weight | 0.4 lbs (185 g) | 0.8 lbs (366 g) |
| Balanced Output | - | No |
| Outputs | - | RCA (variable) |
| DAC Chip | - | 2 x ES9038Q2M |
| Volume Control | - | Hardware knob |
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More worthwhile head-to-heads for Chord Mojo 2:
- SMSL DO400 vs Chord Mojo 2
- D&A Alpha Pro vs Chord Mojo 2
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- Chord Mojo 2 vs Gustard A20H
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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
Chord Mojo 2: $566.86 Amazon eBay
Pros: Audio Science Review measured a SINAD of 110 dB, which is clean for nearly all listening. A rated 600 mW into 30 ohms is enough for most planar magnetic headphones, unusual muscle for something this portable. It takes USB-C, Micro-USB, optical and coaxial inputs, offers both 3.5 mm and 4.4 mm outputs, and includes built-in DSP tone control.
Cons: It costs far more than the TRN Black Pearl, which rates higher and measured cleaner at 117 dB. The Fosi Audio DS3 also matches its rating for much less. At 185 g it is much bigger and heavier than a typical dongle, so it is less convenient to carry with a phone.
Full Chord Mojo 2 review and specifications →
| Released | 2022 (4 years ago) |
|---|---|
| Device Type | DAC and headphone amp |
| Dimensions | 3.3” x 2.4” x 0.9” (83 x 62 x 22.9 mm) |
| Equalizer | Yes (UHD DSP tone control) |
| Headphone Outputs | 3.5 mm, 4.4 mm |
| Inputs | USB-C, Micro-USB, optical, coaxial |
| Output Power (300 ohms) | 90 mW (manufacturer rated) |
| Output Power (32 ohms) | 600 mW into 30 ohms (manufacturer rated) |
| SINAD | 110 dB (measured by Audio Science Review) |
| Weight | 0.4 lbs (185 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