Both are desktop amplifiers, $176 against $169. 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 xDuoo MT-604 reaches 100 dB on 567 of the 567 models here, the Little Dot MK II on 560.
| Specification | Little Dot MK II | xDuoo MT-604 |
|---|---|---|
| Power into 32Ω | 100 mW | 2.0 W |
| Power into 150Ω | 214 mW | 427 mW |
| Power into 300Ω | 300 mW | 213 mW |
| Power into 600Ω | 150 mW | 107 mW |
| Output impedance | not published | not published |
| Output noise | not published | not published |
| Price | $176 | $169 |
| Headphones it reaches 100 dB on out of 567 | 560 | 567 |
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.
7 headphones reach 100 dB on the xDuoo MT-604 but not on the Little Dot MK II — Moondrop COSMO, Moondrop PARA, Moondrop PARA 2, 4 more.
560 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: Little Dot MK II and xDuoo MT-604. Or put either against your own headphones in the source comparison tool.