Both are audio interfaces, $219 against $200. This page puts them side by side on the only three things a maker can be held to — power, output impedance and noise — and then asks the question that actually matters: which headphones do they treat differently?
The MOTU M2 reaches 100 dB on 565 of the 567 models here, the Zoom AMS-44 on 549.
| Specification | MOTU M2 | Zoom AMS-44 |
|---|---|---|
| Power into 32Ω | 333 mW | 30 mW |
| Power into 150Ω | 71 mW | 9.7 mW |
| Power into 300Ω | 36 mW | 5.2 mW |
| Power into 600Ω | 18 mW | 2.7 mW |
| Output impedance | not published | 10 Ω |
| Output noise | not published | not published |
| Price | $219 | $200 |
| Headphones it reaches 100 dB on out of 567 | 565 | 549 |
A figure marked not published is missing from the maker’s own material, which is not the same as being good or bad. Where one of these two publishes a number and the other does not, the comparison on that axis cannot be made at all — and saying so is more useful than guessing.
16 headphones reach 100 dB on the MOTU M2 but not on the Zoom AMS-44 — HiFiMAN HE-6se V2, HiFiMAN HE6 Remastered, HiFiMAN Susvara, 13 more.
549 of the 567 models here reach 100 dB on both. That is a power count and nothing more; whether either source suits a given headphone also depends on the two lines above.
Each has a page of its own with every power figure traced to what the maker published and a full headphone list: MOTU M2 and Zoom AMS-44. Or put either against your own headphones in the source comparison tool.