Short answer
Both are portable players, both at $350.
The Moondrop DISCDREAM2 ULTRA reaches 100 dB on 561 of the 567 models here, the Sony NW-A306 on 530.
| Specification | Moondrop DISCDREAM2 ULTRA | Sony NW-A306 |
|---|---|---|
| Power into 32Ω | 112 mW | 18 mW |
| Power into 150Ω | 24 mW | 3.7 mW |
| Power into 300Ω | 12 mW | 1.9 mW |
| Power into 600Ω | 6.0 mW | 0.90 mW |
| Output impedance | not published | 1.5 Ω unverified |
| Output noise | not published | 5 µV unverified |
| Price | $350 | $350 |
| Headphones it reaches 100 dB on out of 567 | 561 | 530 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Balanced | Moondrop DISCDREAM2 ULTRA | Sony NW-A306 |
|---|---|---|
| Socket | 4.4mm | no separate rating |
| Power into 32Ω | 222 mW | — |
| Power into 300Ω | 24 mW derived | — |
| Output impedance | not published | — |
| Output noise | not published | — |
| Headphones it reaches 100 dB on out of 567 | 565 | — |
Only the Moondrop DISCDREAM2 ULTRA has a separate balanced rating from its maker; through it, it reaches 100 dB on 565 of the 567 models here. The Sony NW-A306 may still have a balanced socket — its spec sheet simply gives no figure for one, so there is nothing to put beside it. Derived figures are worked out from the loads the maker did publish.
| Load | Moondrop DISCDREAM2 ULTRA | Sony NW-A306 |
|---|---|---|
| 32 Ω | Published | Derived |
| 150 Ω | Derived | Derived |
| 300 Ω | Derived | Derived |
| 600 Ω | Derived | Derived |
Only one of these two columns starts from a power rating. Moondrop DISCDREAM2 ULTRA publishes one at 32 Ω; Sony NW-A306 publishes none at any of these four loads, so its column is worked out from power it published at other loads. Both are arithmetic on a maker’s own figures rather than guesses, and the method used for the Sony NW-A306 understates rather than flatters — but at 32 Ω is the only load here at which its maker can be held to a figure.
31 headphones reach 100 dB on the Moondrop DISCDREAM2 ULTRA but not on the Sony NW-A306 — AKG K612 Pro, Abyss AB-1266 Phi CC, Abyss AB-1266 Phi TC, 28 more.
530 of the 567 models here reach 100 dB on both.
Headroom is at a 100 dB SPL peak.
The widest gap on the list is the Audio-Technica ATH-R70X: Moondrop DISCDREAM2 ULTRA has +7 dB of headroom there against -1 dB. 8 dB is about 6.5 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Moondrop DISCDREAM2 ULTRA and Sony NW-A306 because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Moondrop DISCDREAM2 ULTRA headroom | Sony NW-A306 headroom | Moondrop DISCDREAM2 ULTRA hiss | Sony NW-A306 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +29 dB | +27 dB | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +9 dB | +7 dB | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +18 dB | +10 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +14 dB | +6 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +10 dB | +5 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +7 dB | -1 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +3 dB | -5 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +1 dB | -7 dB | not published | not published |
These two cost the same, $350, so price settles nothing. Out of the 567 models here, the Moondrop DISCDREAM2 ULTRA drives 31 models to 100 dB — and on the other side there is no such advantage at all.
Only published figures count here; blank axes are counted separately.
Each in full: Moondrop DISCDREAM2 ULTRA and Sony NW-A306.