Grace Design M900

Description

The Grace Design 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 an 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. The 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. The HIGH power mode is available by connecting the included 2A USB DC power supply to 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.

Features

USB, S/PDIF, and Toslink digital inputs support 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

Specifications

THD+N AT MAXIMUM VOLUME, 1KHZ, 22HZ-22KHZ BW
@1.0V out, no load	<0.002%
@1.0V out, 32 Ohm load	<0.010%

INTERMODULATION DISTORTION SMTPE/DIN 4:1 50HZ, 7KHZ
@1.0V out, no load	<0.008%
@1.0V out, 32 Ohm load	<0.009%

FREQUENCY RESPONSE +/-3DB
Fs=96kHz	0.5-45.9kHz

DYNAMIC RANGE
20-22kHz bandwidth	112 dB
20-22kHz bandwidth and A-weighting filter	115 dB

OUTPUT NOISE
20-22kHz, volume=0-90	-106dBV
A weighting filter, volume = 0-90	-109dBV
20-22kHz, volume=90.5-99.5	-96dBV
A weighting filter, volume = 90.5-99.5	-98dBV

CROSSTALK
100Hz	<107dB
1kHz	<98dB
20kHz	<72dB

ATTENUATION RANGE
0 to -99dB, 0.5dB steps

CROSSTALK TRACKING ACCURACY
+/-0.05dB

MAXIMUM OUTPUT LEVEL, NO LOAD
Low Power Mode	+14.1dBV (5.1V)
High Power Mode	+15.5dBV (6.0V)

IMPEDANCES
Headphone Output	0.08 Ohms
Line Output	47.5 Ohms

INPUT LOCK RANGE	SAMPLE RATE	LOCK RANGE
S/PDIF	44.1kHz	43870-45420Hz
	48kHz	46590-49220Hz
	88.2kHz	87760-90830Hz
	96kHz	93520-98430Hz
	176.4kHz	175700-181640Hz
	192kHz	187050-196380Hz

TOSLINK	44.1kHz	43900-45410Hz
60Hz	48kHz	46590-49190Hz
60Hz	88.2kHz	87840-90830Hz
60Hz	96kHz	93520-97530Hz

USB supported sample rates	44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384kHz