Short answer
Both are dongles, $70 against $109.
The Hidizs S9 Pro reaches 100 dB on 560 of the 567 models here, the DUNU DTC 480 on 554.
| Specification | DUNU DTC 480 | Hidizs S9 Pro |
|---|---|---|
| Power into 32Ω | 65 mW | 100 mW |
| Power into 150Ω | 14 mW | 21 mW |
| Power into 300Ω | 6.9 mW | 11 mW |
| Power into 600Ω | 3.5 mW | 5.3 mW |
| Output impedance | not published | 0.3 Ω unverified |
| Output noise | not published | 4 µV unverified |
| Price | $70 | $109 |
| Headphones it reaches 100 dB on out of 567 | 554 | 560 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Balanced | DUNU DTC 480 | Hidizs S9 Pro |
|---|---|---|
| Socket | 4.4mm | 2.5mm |
| Power into 32Ω | 150 mW | 200 mW |
| Power into 300Ω | 16 mW derived | 21 mW derived |
| Output impedance | not published | not published |
| Output noise | not published | not published |
| Headphones it reaches 100 dB on out of 567 | 563 | 564 |
Through the balanced sockets the Hidizs S9 Pro reaches 100 dB on 564 of the 567 models here and the DUNU DTC 480 on 563. Derived figures are worked out from the loads the maker did publish.
| Load | DUNU DTC 480 | Hidizs S9 Pro |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Derived | Derived |
| 600 Ω | Derived | Derived |
Both makers publish a power rating. DUNU DTC 480 publishes at 32 Ω; Hidizs S9 Pro at 32 Ω. The other rows are worked out from those.
The two publish at the same loads, which is the one case where the rows of this table can be read straight across.
6 headphones reach 100 dB on the Hidizs S9 Pro but not on the DUNU DTC 480 — HiFiMAN HE-6se V2, HiFiMAN HE6 Remastered, HiFiMAN Susvara, 3 more.
554 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 Sennheiser HD 600: Hidizs S9 Pro has +2 dB of headroom there against +0 dB. 2 dB is about 1.6 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for DUNU DTC 480 and Hidizs S9 Pro because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | DUNU DTC 480 headroom | Hidizs S9 Pro headroom | DUNU DTC 480 hiss | Hidizs S9 Pro hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +27 dB | +28 dB | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +7 dB | +8 dB | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +16 dB | +18 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +11 dB | +13 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +8 dB | +10 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +4 dB | +6 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +0 dB | +2 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | -2 dB | +0 dB | not published | not published |
The Hidizs S9 Pro costs $39 more than the DUNU DTC 480. Out of the 567 models here, that difference buys 6 more models driven to 100 dB.
Nothing runs the other way: there is no axis here on which the cheaper of the two does better.
Only published figures count here; blank axes are counted separately.
Each in full: DUNU DTC 480 and Hidizs S9 Pro.