Grace Design M900

Compact, Portable Headphone Amp / DAC / Preamp


The m900 is a portable, desktop friendly headphone amplifier / DAC / preamp combo designed to give
audio professionals and enthusiasts musical and transparent audio playback from USB, S/PDIF or
TOSLINK sources. For small DAW studio setups, portable laptop editing or mixing rigs, or just pure
playback enjoyment, the m900 provides the same analog and DAC quality as our large monitor
controllers, but in a rugged, portable and surprisingly affordable unit.
The m900 DAC uses the latest generation AKM 4490 chip, which features 32-bit processing and supports
sample rates up to 384kHz PCM or 256x DSD. The USB interface operates in asynchronous mode
allowing the m900 to be the clock master which makes the system immune to USB bus jitter. S/PDIF and
Toslink inputs allow the m900 to enhance to any DAW interface with true reference quality D/A
conversion, headphone monitoring and stereo speaker control.
An intelligent power supply design allows for two power operation modes – LOW and HIGH. LOW power
mode is from USB connector #1, which provides bus power along with data, allowing the m900 to
operate from a single connection to your computer. HIGH power power mode is available by connecting
the included 2A USB DC power supply to the USB connector #2, which provides additional power for
harder to drive headphones.
Transimpedance amplifier topology coupled to a zero ohm output impedance driver provides
headphone performance that is incredibly spacious and transparent with a tight, enveloping low end.
Our latest generation crossfeed circuit rounds out the design by simulating an acoustic listening
environment in the headphones. Familiar tracks become new again with surprise details, while audio
production tasks like tracking, mixing and editing happen faster and easier.
After many years of honing our DAC and headphone amplifier designs, the m900 distills the best of what
we've learned in a compact, rugged and simple unit. Whether in the studio, on your desk or on the road,
the m900 will bring you closer to the music you love.

04/2018 – m900 Firmware v2.3 Available
Implements the following new features: Mono Mode, Left minus Right, Channel Balance adjust,
Monitoring Modes (stereo, L&R swapped, left in both channels, right in both channels, left channel only,
right channel only). Visit our support page for download and installation information.
USB, S/PDIF and Toslink digital inputs, supports up to 192kHz (Toslink up to 96kHz)
Asynchronous USB interface for jitter free computer audio playback, supports up to 384kHz PCM and
256x DSD
Dual zero ohm output impedance headphone outputs
Unbalanced level controlled outputs via RCA for connecting to a stereo monitor system
Compact, portable chassis perfect for travel, desktop or studio
Mono mode, Left minus Right mode
6 monitoring modes: stereo, L&R swapped, left in both channels, right in both channels, left channel
only, right channel only
Channel balance adjustment
Low power mode via USB Bus power
High power mode via included USB 2A power supply
4 different DAC filter settings to tailor playback performance to personal preference
Simple user setup menu for setup and calibration
7 segment LED display displays level and setup menu information
Large rotary encoder for volume control and setup menu navigation
Made in Lyons, CO USA
5 year transferable Warranty


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