Short answer: the MOTU M4. It ranks #7 of 17 audio interfaces by measured performance (rated 3.8/5) at $279.95 and is still sold new; the MOTU 624 ranks #8 (rated 3.7/5) and is discontinued, so it is only an option used.
What the MOTU M4 does well: Audio Science Review measured 111 dB SINAD from its ESS Sabre32 Ultra DAC, clean for nearly all listening and competitive with good budget DACs. The tradeoff: MOTU doesn’t publish a 32 ohm headphone power figure, and Audio Science Review measured just 18 mW into 300 ohms, calling the headphone amplifier its weakest part, so demanding headphones may run out of volume.
The case for the MOTU 624: Audio Science Review measured 112 dB SINAD from its outputs, clean enough for nearly all listening. The tradeoff: It is discontinued and no longer sold new.
Buy the MOTU M4. It is rated higher and still sold new, while the MOTU 624 is discontinued.
Looking for alternatives? See the complete Headphone Amps and DACs rankings.
Specifications Side By Side
| MOTU M4 | MOTU 624 | |
|---|---|---|
| Price | $279.95 | $795 Discontinued |
| Ranked | #7 of 17 in Audio Interfaces | #8 of 17 in Audio Interfaces |
| Device Type | Audio interface | Audio interface |
| SINAD | 111 dB (measured by Audio Science Review) | 112 dB (measured by Audio Science Review) |
| Inputs | 2 XLR/TRS combo (mic/line/Hi-Z), 2 balanced 6.35 mm line, MIDI in, USB-C | 2 XLR mic, 2 front-panel Hi-Z guitar, 8 ADAT optical |
| Outputs | 4 balanced 6.35 mm TRS, 4 RCA (mirrored), headphone | dedicated main outs, 8 ADAT optical |
| Headphone Outputs | 1 x 6.35 mm | 1 x 6.35 mm |
| Balanced Output | Yes (TRS monitor outs) | - |
| DAC Chip | ESS Sabre32 Ultra | ESS Sabre32 |
| Volume Control | Hardware knob | - |
| Dimensions | 8.3” x 1.8” x 4.3” (210 x 45 x 108 mm) | 8.6” x 1.7” x 7” (218 x 44 x 178 mm) |
| Weight | 2 lbs (920 g) | 2.2 lbs (1.0 kg) |
| Output Power (300 ohms) | 18 mW (measured by Audio Science Review) | - |
Related Amp and DAC Comparisons
More worthwhile head-to-heads for MOTU M4:
- Topping M62 vs MOTU M4
- Topping E2x2 vs MOTU M4
- Lynx Hilo 2 USB vs MOTU M4
- MOTU M4 vs MOTU UltraLite-mk5
- MOTU M4 vs MOTU M6
Prices on this page were last checked October 13, 2026 at 3:17 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
MOTU M4: $279.95 Amazon $279.95 eBay
Pros: Audio Science Review measured 111 dB SINAD from its ESS Sabre32 Ultra DAC, clean for nearly all listening and competitive with good budget DACs. It adds two balanced line inputs to the two XLR/TRS combo inputs, has four balanced TRS outputs with mirrored RCA outputs, MIDI in and a hardware volume knob, and Audio Science Review found its recording converter better than many computer interfaces.
Cons: MOTU doesn’t publish a 32 ohm headphone power figure, and Audio Science Review measured just 18 mW into 300 ohms, calling the headphone amplifier its weakest part, so demanding headphones may run out of volume. The Topping M62 rates higher for less.
Full MOTU M4 review and specifications →
| Released | 2020 (6 years ago) |
|---|---|
| Balanced Output | Yes (TRS monitor outs) |
| DAC Chip | ESS Sabre32 Ultra |
| Device Type | Audio interface |
| Dimensions | 8.3” x 1.8” x 4.3” (210 x 45 x 108 mm) |
| Headphone Outputs | 1 x 6.35 mm |
| Inputs | 2 XLR/TRS combo (mic/line/Hi-Z), 2 balanced 6.35 mm line, MIDI in, USB-C |
| Output Power (300 ohms) | 18 mW (measured by Audio Science Review) |
| Outputs | 4 balanced 6.35 mm TRS, 4 RCA (mirrored), headphone |
| SINAD | 111 dB (measured by Audio Science Review) |
| Volume Control | Hardware knob |
| Weight | 2 lbs (920 g) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
MOTU 624: $795 Discontinued eBay
Pros: Audio Science Review measured 112 dB SINAD from its outputs, clean enough for nearly all listening. Alongside two XLR mic inputs and two front panel guitar inputs it has eight channels of ADAT optical in and out for expanding the setup, and the reviewer found its browser based control software rich and flexible.
Cons: It is discontinued and no longer sold new. Audio Science Review found its ADC a weak link next to other interfaces it had tested and its DAC short of the best consumer DACs, and MOTU doesn’t publish a 32 ohm headphone power figure. The MOTU UltraLite-mk5 measures similarly and is still sold.
Full MOTU 624 review and specifications →
| DAC Chip | ESS Sabre32 |
|---|---|
| Device Type | Audio interface |
| Dimensions | 8.6” x 1.7” x 7” (218 x 44 x 178 mm) |
| Headphone Outputs | 1 x 6.35 mm |
| Inputs | 2 XLR mic, 2 front-panel Hi-Z guitar, 8 ADAT optical |
| Outputs | dedicated main outs, 8 ADAT optical |
| SINAD | 112 dB (measured by Audio Science Review) |
| Weight | 2.2 lbs (1.0 kg) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons