Grace Design m900: power output and what it will drive

The Grace Design m900 is a desktop amplifier at $660. It delivers 1.0 W into 32Ω and 115 mW into 300Ω, which ranks it 78 of 280 for raw power among the sources in this database.

Measured at 100 dB SPL it has comfortable headroom on 565 of the 567 dynamic and planar headphones catalogued here and enough but not generous on 2. Power is published at 16Ω, 32Ω, 50Ω, 300Ω, 600Ω; the rest of the table is derived from those figures.

The manufacturer publishes 1.9 W into 16Ω, 1.0 W into 32Ω, 680 mW into 50Ω, 115 mW into 300Ω, 57 mW into 600Ω. The rest of the table is worked out from those.

Derived rows hold output voltage steady, as an amplifier does (method).

Source: gracedesign.com.

Easiest to hardest to drive, with headroom at a 100 dB SPL peak.

At 5.01 µV of output noise, here is where that noise lands in the five most revealing in-ears in the database.

This one hisses. With the most sensitive in-ears in the database its own noise lands around 35 dB SPL, which you will hear between tracks and in quiet passages.

At 0.08Ω output impedance this source satisfies the one-eighth rule with every headphone in the database, down to the 3Ω in-ears. Nothing here will have its frequency response shaped by the source.

Check any pair.

Of the 280 sources here, 9 do everything the Grace Design m900 does as a headphone output: reach 100 dB on every headphone it reaches, stay inside the one-eighth rule wherever it does and stay under the audible-hiss threshold wherever it does. The cheapest of them is the Schiit Magni Unity at $119, against this one’s $660 — $541 less.

This counts the headphone output only; inputs, converters, the volume control and the build are outside it.

Compared with its closest rivals: vs Aune S17 Pro EVO · vs Lake People G111 Mk II · vs Rupert Neve RNHP · vs Schiit Valhalla 3 · vs Singxer SA-1.

Compare any two or match your own headphones. Every Grace Design source here.