The Focusrite Scarlett Solo 4th gen is a audio interface at $139. It delivers 31 mW into 32Ω and 22 mW into 300Ω, which ranks it 146 of 156 for raw power among the sources in this database.
Measured at 100 dB SPL it has comfortable headroom on 275 of the 396 dynamic and planar headphones catalogued here, enough but not generous on 104, only marginal on 13 and not enough power for 4.
The manufacturer publishes 32 mW into 33Ω, 22 mW into 300Ω. Everything else in the table above is worked out from those figures, and this table says which is which.
Derivation holds output voltage steady between and beyond the published loads rather than output power, because that is what an amplifier actually does. The full method is written up here.
Source: userguides.focusrite.com.
| Load | Power | Status | How it was arrived at |
|---|---|---|---|
| 32 Ω | 31 mW | Derived | beyond the published loads, holding output voltage constant — which understates rather than flatters |
| 33 Ω | 32 mW | Published | the manufacturer publishes this figure at this exact load |
| 150 Ω | 19 mW | Derived | worked out between two published loads, holding output voltage linear between them |
| 300 Ω | 22 mW | Published | the manufacturer publishes this figure at this exact load |
| 600 Ω | 11 mW | Derived | beyond the published loads, holding output voltage constant — which understates rather than flatters |
Ordered from easiest to hardest to drive. Headroom is measured at 100 dB SPL, which is louder than almost anyone listens — a small negative number means the source still plays loud, just without reserve for peaks.
These figures come from each manufacturer's own sensitivity rating. A handful of planars — the HiFiMAN Susvara and HE-6se and the Abyss AB-1266 in particular — are widely reported to need far more than their published sensitivity implies, so treat a bare pass on those as optimistic rather than settled.
| Headphone | Impedance | dB/mW | Needs | Headroom | Verdict |
|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 114.0 | 0.04 mW | +23 dB | Comfortable damping |
| 64 Audio U12t | 13 Ω | 108.0 | 0.16 mW | +19 dB | Comfortable damping |
| Shure SE215 | 17 Ω | 107.0 | 0.20 mW | +19 dB | Comfortable damping |
| Moondrop Aria | 32 Ω | 107.1 | 0.19 mW | +22 dB | Comfortable damping |
| Audeze LCD-X 2021 | 20 Ω | 103.0 | 0.50 mW | +16 dB | Comfortable damping |
| Truthear Hexa | 21 Ω | 103.1 | 0.49 mW | +16 dB | Comfortable damping |
| Sennheiser HD 25 (1-II) | 70 Ω | 108.0 | 0.16 mW | +21 dB | Comfortable damping |
| Sennheiser IE 200 | 18 Ω | 101.6 | 0.69 mW | +14 dB | Comfortable damping |
| Sony MDR-7506 | 63 Ω | 106.0 | 0.25 mW | +20 dB | Comfortable damping |
| Meze 99 Classics | 32 Ω | 103.0 | 0.50 mW | +18 dB | Comfortable damping |
| Focal Clear MG | 55 Ω | 104.0 | 0.40 mW | +18 dB | Comfortable damping |
| Philips SHP9500 | 32 Ω | 101.0 | 0.79 mW | +16 dB | Comfortable damping |
| Focal Utopia | 80 Ω | 104.0 | 0.40 mW | +17 dB | Comfortable damping |
| Meze Empyrean | 32 Ω | 100.0 | 1.0 mW | +15 dB | Comfortable damping |
| Campfire Audio Andromeda 2020 | 9 Ω | 94.0 | 4.0 mW | +3 dB | Enough damping |
| Etymotic ER2SE | 15 Ω | 96.0 | 2.5 mW | +8 dB | Enough damping |
| AKG K371 | 32 Ω | 99.1 | 1.2 mW | +14 dB | Comfortable damping |
| Audio-Technica ATH-M50X | 38 Ω | 99.0 | 1.3 mW | +14 dB | Comfortable damping |
| Beyerdynamic DT 900 Pro X | 48 Ω | 100.0 | 1.0 mW | +14 dB | Comfortable damping |
| Audeze LCD-2 Classic | 70 Ω | 101.0 | 0.79 mW | +14 dB | Comfortable damping |
| Grado SR80x | 38 Ω | 98.0 | 1.6 mW | +13 dB | Comfortable damping |
| Sennheiser HD 560S | 120 Ω | 100.8 | 0.83 mW | +14 dB | Comfortable damping |
| HiFiMAN Edition XS | 18 Ω | 92.0 | 6.3 mW | +4 dB | Enough damping |
| HiFiMAN Arya Stealth | 32 Ω | 94.0 | 4.0 mW | +9 dB | Enough damping |
| Dan Clark Audio AEON 2 Closed | 13 Ω | 90.0 | 10 mW | +1 dB | Marginal damping |
| Audeze LCD-5 | 14 Ω | 90.0 | 10 mW | +1 dB | Marginal damping |
| HiFiMAN Sundara | 37 Ω | 94.0 | 4.0 mW | +9 dB | Enough damping |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 102.0 | 0.63 mW | +15 dB | Comfortable damping |
| HiFiMAN HE400se | 25 Ω | 91.0 | 7.9 mW | +5 dB | Enough damping |
| Dan Clark Audio Stealth | 23 Ω | 90.0 | 10 mW | +3 dB | Enough damping |
| Fostex T50RP MK3 | 50 Ω | 92.0 | 6.3 mW | +6 dB | Enough damping |
| AKG K702 | 62 Ω | 92.9 | 5.1 mW | +7 dB | Enough damping |
| ZMF Verite Closed | 300 Ω | 99.0 | 1.3 mW | +12 dB | Comfortable damping |
| Sennheiser HD 650 | 300 Ω | 97.8 | 1.7 mW | +11 dB | Comfortable damping |
| Sennheiser HD 800S | 300 Ω | 96.8 | 2.1 mW | +10 dB | Comfortable damping |
| Beyerdynamic DT 770 Pro (250Ω) | 250 Ω | 96.0 | 2.5 mW | +9 dB | Enough damping |
| Audio-Technica ATH-R70X | 470 Ω | 98.0 | 1.6 mW | +9 dB | Enough |
| ZMF Atrium | 300 Ω | 96.0 | 2.5 mW | +9 dB | Enough damping |
| Abyss AB-1266 Phi TC | 50 Ω | 88.0 | 16 mW | +2 dB | Marginal damping |
| Sennheiser HD 600 | 300 Ω | 91.8 | 6.6 mW | +5 dB | Enough damping |
| HiFiMAN Susvara | 60 Ω | 83.0 | 50 mW | -3 dB | Not enough damping |
The manufacturer does not publish an output noise figure for this source, so the hiss estimate that runs on every other page here cannot be run on this one. Rather than substitute a plausible number, this page leaves the question open.
If you know the noise figure from a measurement you trust, the hiss calculator takes it directly and tells you where that noise lands in your own in-ears.
At 50 Ω output impedance, the one-eighth rule says this source suits headphones of 400.0Ω and above. 390 of the 396 models here fall below that, mostly multi-driver in-ears, where the mismatch tilts the frequency response audibly rather than subtly.
The rule is a rule of thumb, not physics: a source impedance below one eighth of the headphone's keeps the interaction under about 1 dB. The checker works it out for any pair.
$129 · 22 mW into 32Ω · 50 Ω out
Compare →$149 · 27 mW into 32Ω · not published out
Compare →$149 · 139 mW into 32Ω · 10 Ω out
Compare →$119 · 32 mW into 32Ω · not published out
Compare →$199 · 31 mW into 32Ω · 50 Ω out
Compare →$199 · 112 mW into 32Ω · not published out
Compare →Or put any two side by side in the source comparison tool, or run your own headphones through the amplifier matcher.