The Denon AH-D2000 is 25Ω at 106.0 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.
The AH-MM400 needs 1.0 dB more than the AH-D2000 to reach the same loudness — 0.32 mW against 0.25 mW.
| Specification | AH-D2000 | AH-MM400 |
|---|---|---|
| Impedance | 25 Ω | 40 Ω |
| Sensitivity | 106.0 dB/mW | 105.0 dB |
| Sensitivity (voltage) | 122.0 dB/V | 119.0 dB/V |
| Power for 100 dB | 0.25 mW | 0.32 mW |
| Voltage for 100 dB | 79 mV | 0.11 V |
| Current for 100 dB | 3.2 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-D2000 (Shanling H5).
2 sources stay below the audible-hiss threshold with the AH-MM400 but cross it with the AH-D2000 (FiiO BTR11, Rupert Neve RNHP).
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-D2000 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.