The Denon AH-D7200 is 25Ω at 105.0 dB/mW; the Denon AH-MM400 is 40Ω at 105.0 dB (no figure from the maker at all). 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 | AH-D7200 | AH-MM400 |
|---|---|---|
| Impedance | 25 Ω | 40 Ω |
| Sensitivity | 105.0 dB/mW | 105.0 dB |
| Sensitivity (voltage) | 121.0 dB/V | 119.0 dB/V |
| Power for 100 dB | 0.32 mW | 0.32 mW |
| Voltage for 100 dB | 89 mV | 0.11 V |
| Current for 100 dB | 3.6 mA | 2.8 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 3.12 Ω | 5.00 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
One caution before reading the rows. For Denon AH-MM400 the maker publishes no sensitivity figure at all. The number in the table was collected when this database was first built and has never been traced to a manufacturer document, so treat every row below it as an estimate rather than a specification.
Every source in the database that drives one of them drives the other. On power, the choice between these two changes nothing about what amplifier you need.
1 source is low enough in output impedance for the AH-MM400 under the one-eighth rule but not for the AH-D7200 (Shanling H5).
280 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: Denon AH-D7200 and Denon AH-MM400. Each figure on this page is labelled on those pages with where it came from, including the ones Denon never published — what that maker publishes, counted.