The Beyerdynamic DT 990 Edition (250Ω) is 250Ω at 96.0 dB (no reference unit printed); the Beyerdynamic DT 990 Edition (32Ω) is 32Ω at 96.0 dB (no reference unit printed). This page is only about what they ask of an amplifier — not how they sound, which no specification on either sheet can tell you.
In amplifier terms these two are the same headphone. The gap between what they need for 100 dB is under half a decibel, which is smaller than the step between two clicks of most volume controls.
| Specification | DT 990 Edition (250Ω) | DT 990 Edition (32Ω) |
|---|---|---|
| Impedance | 250 Ω | 32 Ω |
| Sensitivity | 96.0 dB | 96.0 dB |
| Sensitivity (voltage) | 102.0 dB/V | 110.9 dB/V |
| Power for 100 dB | 2.5 mW | 2.5 mW |
| Voltage for 100 dB | 0.79 V | 0.28 V |
| Current for 100 dB | 3.2 mA | 8.9 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 31.25 Ω | 4.00 Ω |
| Sources that reach 100 dB out of 280 | 277 | 280 |
One caution before reading the rows. Beyerdynamic DT 990 Edition (250Ω) and Beyerdynamic DT 990 Edition (32Ω) printed a decibel figure with no reference unit, so this page reads it as per milliwatt. If it is really per volt, each of them needs far more than the table says. Why the two readings differ by so much.
3 of the 280 sources have the power for the DT 990 Edition (32Ω) but not for the DT 990 Edition (250Ω) — Apple USB-C dongle (EU), Steinberg UR22C, Sony NW-A306.
19 sources are low enough in output impedance for the DT 990 Edition (250Ω) under the one-eighth rule but not for the DT 990 Edition (32Ω) (Zoom AMS-22, Arturia MiniFuse 2, Arturia MiniFuse 1, 16 more).
277 of the 280 sources here reach 100 dB on both. That count is about power only — the output-impedance and hiss lines above are separate questions, and a source can pass this one and fail those.
Each model has a page of its own with the full source list, the hiss estimate and the provenance of every figure above: Beyerdynamic DT 990 Edition (250Ω) and Beyerdynamic DT 990 Edition (32Ω). Each figure on this page is labelled on those pages with where it came from, including the ones Beyerdynamic never published — what that maker publishes, counted.