The Hidizs S9 Pro Plus is a USB dongle at $139. It delivers 138 mW into 32Ω and 15 mW into 300Ω, which ranks it 184 of 280 for raw power among the sources in this database.
Measured at 100 dB SPL it has comfortable headroom on 506 of the 567 dynamic and planar headphones catalogued here, enough but not generous on 48, only marginal on 8 and not enough power for 5. Long-running S9 line, refreshed. Both jacks on a body barely larger than the cable.
The manufacturer publishes 138 mW into 32Ω. The rest of the table is worked out from those.
The balanced output is rated separately: 180 mW into 32Ω through the 4.4mm jack.
Derived rows hold output voltage steady, as an amplifier does (method).
Source: hidizs.net.
| Load | Power | Status | How it was arrived at |
|---|---|---|---|
| 32 Ω | 138 mW | Published | the manufacturer publishes this figure at this exact load |
| 150 Ω | 29 mW | Derived | beyond the published loads, holding output voltage constant — which understates rather than flatters |
| 300 Ω | 15 mW | Derived | beyond the published loads, holding output voltage constant — which understates rather than flatters |
| 600 Ω | 7.4 mW | Derived | beyond the published loads, holding output voltage constant — which understates rather than flatters |
Easiest to hardest to drive, with headroom at a 100 dB SPL peak.
| Headphone | Impedance | Sensitivity | Needs | Headroom | Verdict |
|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 114.0 dB/mW | 0.04 mW | +30 dB | Comfortable |
| 64 Audio U12t | 12.6 Ω | 108.0 dB/mW | 0.16 mW | +25 dB | Comfortable |
| Shure SE215 | 17 Ω | 107.0 dB/mW | 0.20 mW | +26 dB | Comfortable |
| Moondrop Aria | 32 Ω | 107.1 dB/mW | 0.19 mW | +28 dB | Comfortable |
| Audeze LCD-X 2021 | 20 Ω | 103.0 dB/mW | 0.50 mW | +22 dB | Comfortable |
| Truthear Hexa | 20.5 Ω | 103.1 dB/mW | 0.49 mW | +23 dB | Comfortable |
| Sennheiser IE 200 | 18 Ω | 101.6 dB/mW | 0.69 mW | +21 dB | Comfortable |
| Sony MDR-7506 | 63 Ω | 106.0 dB/mW | 0.25 mW | +24 dB | Comfortable |
| Meze 99 Classics | 32 Ω | 103.0 dB/mW | 0.50 mW | +24 dB | Comfortable |
| Focal Clear MG | 55 Ω | 104.0 dB/mW | 0.40 mW | +23 dB | Comfortable |
| Philips SHP9500 | 32 Ω | 101.0 dB | 0.79 mW | +22 dB | Comfortable |
| Focal Utopia | 80 Ω | 104.0 dB/mW | 0.40 mW | +21 dB | Comfortable |
| Meze Empyrean | 32 Ω | 100.0 dB | 1.0 mW | +21 dB | Comfortable |
| Campfire Audio Andromeda 2020 | 9 Ω | 94.0 dB | 4.0 mW | +10 dB | Enough |
| Etymotic ER2SE | 15 Ω | 96.0 dB/mW | 2.5 mW | +14 dB | Comfortable |
| AKG K371 | 32 Ω | 99.1 dB/mW | 1.2 mW | +20 dB | Comfortable |
| Audio-Technica ATH-M50X | 38 Ω | 99.0 dB/mW | 1.3 mW | +20 dB | Comfortable |
| Beyerdynamic DT 900 Pro X | 48 Ω | 100.0 dB/mW | 1.0 mW | +20 dB | Comfortable |
| Audeze LCD-2 Classic | 70 Ω | 101.0 dB/mW | 0.79 mW | +19 dB | Comfortable |
| Grado SR80x | 38 Ω | 98.0 dB/mW | 1.6 mW | +19 dB | Comfortable |
| Sennheiser HD 560S | 120 Ω | 100.8 dB/mW | 0.83 mW | +16 dB | Comfortable |
| HiFiMAN Edition XS | 18 Ω | 92.0 dB | 6.3 mW | +11 dB | Comfortable |
| HiFiMAN Arya Stealth | 32 Ω | 94.0 dB | 4.0 mW | +15 dB | Comfortable |
| Dan Clark Audio AEON 2 Closed | 13 Ω | 90.0 dB/mW | 10 mW | +7 dB | Enough |
| Audeze LCD-5 | 14 Ω | 90.0 dB/mW | 10 mW | +8 dB | Enough |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 102.0 dB/mW | 0.63 mW | +14 dB | Comfortable |
| HiFiMAN HE400se | 25 Ω | 91.0 dB | 7.9 mW | +11 dB | Comfortable |
| HiFiMAN Sundara | 32 Ω | 92.0 dB | 6.3 mW | +13 dB | Comfortable |
| Dan Clark Audio Stealth | 23 Ω | 90.0 dB/mW | 10 mW | +10 dB | Enough |
| Fostex T50RP MK3 | 50 Ω | 92.0 dB/mW | 6.3 mW | +11 dB | Comfortable |
| AKG K702 | 62 Ω | 92.9 dB/mW | 5.1 mW | +11 dB | Comfortable |
| ZMF Verite Closed | 300 Ω | 99.0 dB/mW | 1.3 mW | +11 dB | Comfortable |
| Sennheiser HD 650 | 300 Ω | 97.8 dB/mW | 1.7 mW | +9 dB | Enough |
| Sennheiser HD 800S | 300 Ω | 96.8 dB/mW | 2.1 mW | +8 dB | Enough |
| Beyerdynamic DT 770 Pro (250Ω) | 250 Ω | 96.0 dB | 2.5 mW | +8 dB | Enough |
| Audio-Technica ATH-R70X | 470 Ω | 98.0 dB/mW | 1.6 mW | +8 dB | Enough |
| ZMF Atrium | 300 Ω | 96.0 dB/mW | 2.5 mW | +8 dB | Enough |
| Abyss AB-1266 Phi TC | 50 Ω | 88.0 dB/mW | 16 mW | +7 dB | Enough |
| Sennheiser HD 600 | 300 Ω | 91.8 dB/mW | 6.6 mW | +3 dB | Enough |
| HiFiMAN Susvara | 60 Ω | 83.0 dB | 50 mW | +2 dB | Marginal |
The manufacturer does not publish an output noise figure for this source, so there is no hiss estimate here. If you have a measured figure, the hiss calculator takes it.
The manufacturer does not publish an output impedance for this source. Without it, nothing here can say how this source will behave with a multi-driver in-ear.
With a measured figure, the checker works out the consequence.
| Source | Type | Price | Into 300 Ω | Output impedance | Output noise |
|---|---|---|---|---|---|
| FiiO KA11 | USB dongle | $29 | 22 mW | 0.7 Ω | 1.7 µV |
| ddHiFi TC35AL | USB dongle | $46 | 22 mW | not published | not published |
| ddHiFi TC35Air | USB dongle | $46 | 22 mW | not published | not published |
Of the 280 sources here, 19 do everything the Hidizs S9 Pro Plus does as a headphone output: reach 100 dB on every headphone it reaches. The cheapest of them is the FiiO KA11 at $29, against this one’s $139 — $110 less.
The cheaper one also publishes an output impedance and a noise figure, which the Hidizs S9 Pro Plus does not — so on the paperwork it is ahead, not merely level.
This counts the headphone output only; inputs, converters, the volume control and the build are outside it.
$140 · 285 mW into 32Ω · output Ω not published
Compare →$149 · 140 mW into 32Ω · 1.0 Ω out
Compare →$119 · 125 mW into 32Ω · 0.2 Ω out
Compare →$160 · 80 mW into 32Ω · output Ω not published
Compare →$109 · 100 mW into 32Ω · 0.3 Ω out
Compare →$109 · 180 mW into 32Ω · 0.8 Ω out
Compare →Compared with its closest rivals: vs ddHiFi TC44Grip · vs FiiO KA15 · vs FiiO KA17 · vs Hidizs S9 Pro · vs Hidizs SD2 · vs Tanchjim LUNA.