Both are portable players, $479 against $2959. 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 Shanling M9 Plus reaches 100 dB on 566 of the 567 models here, the Shanling M3 Ultra on 562.
| Specification | Shanling M3 Ultra | Shanling M9 Plus |
|---|---|---|
| Power into 32Ω | 140 mW | 520 mW |
| Power into 150Ω | 30 mW | 111 mW |
| Power into 300Ω | 15 mW | 55 mW |
| Power into 600Ω | 7.5 mW | 28 mW |
| Output impedance | 1 Ω | 1 Ω |
| Output noise | not published | not published |
| Price | $479 | $2959 |
| Headphones it reaches 100 dB on out of 567 | 562 | 566 |
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.
4 headphones reach 100 dB on the Shanling M9 Plus but not on the Shanling M3 Ultra — Moondrop COSMO, Moondrop PARA, Symphonium Crimson, 1 more.
562 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: Shanling M3 Ultra and Shanling M9 Plus. Or put either against your own headphones in the source comparison tool.