On power: 38 of the 39 portable players here reach 100 dB SPL on the Beyerdynamic DT 990 Pro (250Ω). It needs 2.5 mW at its 250Ω, and 1 of them do not get there.
Power is one of three questions and the one that goes wrong least often. The other two — whether the source’s output impedance leaves the frequency response alone, and whether you will hear its noise floor — are answered further down, separately, because a source can pass one and fail another.
The 1 that fall short are Sony NW-A306. The closest of them, the Sony NW-A306, delivers 2.3 mW into 250Ω against the 2.5 mW needed — 0.5 dB short.
The cheapest one that does reach it is the Hidizs AP80 Pro Max at $179, which delivers 9.0 mW into 250Ω — 6 dB of headroom over the 2.5 mW this headphone needs for 100 dB SPL.
100 dB SPL is a peak level, not a listening level. If you listen at 85 dB the same headphone needs 0.08 mW, which is 15 dB less, and the answer above changes for most of the category. The model page has the full ladder.
Under the one-eighth rule the Beyerdynamic DT 990 Pro (250Ω) wants a source below 31.25Ω. Of the 26 portable players here that publish an output impedance, 26 are under it and 0 are not.
The other 13 publish nothing at all on this, so they are not on either side of that count. This site leaves them blank rather than assuming a figure.
Hiss depends on the source’s own noise floor and on how sensitive the headphone is. At 96.0 dB and 250Ω, the Beyerdynamic DT 990 Pro (250Ω) turns one microvolt of source noise into about -18 dB SPL — and the threshold where that stops being noticeable in a quiet room is around 20 dB SPL.
Of the 12 portable players here that publish a noise figure, 12 stay below that threshold with this headphone and 0 cross it.
The remaining 27 publish no noise figure, so they cannot be placed on either side.
| Source | Price | Into 250Ω | Output impedance | Hiss in these | Power verdict |
|---|---|---|---|---|---|
| TempoTec Variations V3 Blaze | $179 | 106 mW | not published | not published | Comfortable |
| FiiO JM21 | $199 | 35 mW | 1 Ω | -14 dB SPL | Comfortable |
| Shanling H5 | $369 | 29 mW | 4.7 Ω | not published | Comfortable |
| TempoTec Variations V6 | $369 | 42 mW | not published | not published | Comfortable |
| iBasso DX180 | $480 | 34 mW | 0.6 Ω | not published | Comfortable |
| FiiO M11S | $499 | 27 mW | 1.5 Ω | -13 dB SPL | Comfortable |
| FiiO M21 | $599 | 54 mW | 1 Ω | -12 dB SPL | Comfortable |
| Cayin N3 Ultra | $649 | 32 mW | 0.5 Ω | not published | Comfortable |
| FiiO M33 R2R | $730 | 70 mW | 0.8 Ω | -3 dB SPL | Comfortable |
| HiBy R6 Pro II | $750 | 168 mW | not published | not published | Comfortable |
| FiiO M15S | $799 | 104 mW | 1.4 Ω | -8 dB SPL | Comfortable |
| Astell&Kern SR35 | $800 | 38 mW | 1.1 Ω | not published | Comfortable |
Sorted by how many of the three questions the source answers well, then by price. A blank in a column is a blank in the manufacturer’s own documentation, not a zero.
The Beyerdynamic DT 990 Pro (250Ω) on other categories: USB dongles · desktop amplifiers · audio interfaces.
The Beyerdynamic DT 990 Pro (250Ω) page has every source in the database against this headphone, and the matcher takes your own numbers.