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
PC 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 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. Weather in the studio, on your desk or
on the road, the m900 will bring you closer to the music you love.
FEATURES
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 DSDDual zero ohm output impedance headphone outputsUnbalanced level controlled outputs via RCA for connecting to a stereo monitor systemCompact, portable chassis perfect for travel, desktop or studioLow power mode via USB Bus powerHigh power mode via included USB 2A power supply4 different DAC filter settings to tailor playback performance to personal preferenceSimple user setup menu for setup and calibration7 segment LED display displays level and setup menu informationLarge rotary encoder for volume control and setup menu navigationMade in Lyons, CO USA5 year transferable WarrantyPOWER MODES
Low Power, USB input - One USB cable from the computer to the m900 #1 USB input. m900 receives power and audio from the computer.
High Power, USB input - One USB
cable from the computer to the m900 #1 USB input and one USB cable from
the external 2A DC power supply to the m900 #2 high power DC input
connector. The m900 receives audio from the computer and receives power
from the external DC supply.
Low Power, S/PDIF or TOSLINK input
- One USB cable from a standard USB power source (computer or 0.5A USB
power supply) connected to the m900 #1 USB input. TOSLINK or S/PDIF
input connected. (This would be an unusual setup where you don’t have
access to a high power DC power supply.)
High Power, S/PDIF or TOSLINK input
- One USB cable from the 2A DC power supply to the m900 #2 high power
DC input connector. TOSLINK or S/PDIF input connected. m900 receives
audio from TOSLINK and power from the external DC supply.
Self Powered Mode - This mode is
for connecting your mobile device (iOS, android) to the m900. Mobile
devices generally cannot provide any power. In this mode the m900 will
report that it is self powered. To enter self powered mode, first
connect the USB cable from the external 2A DC power supply to the m900
#2 high power DC input connector, then connect your device to the m900
#1 USB input. For iOS, you will need the ‘Apple Lightning to USB Camera
Adapter’, for supported Android devices you will need an ‘On The Go’ USB
cable.
SECIFICATIONS
| THD+N 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 |
|
112dB |
| 20-22kHz bandwidth and A weighting filter |
|
115dB |
| 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 |
|
|
| Channel 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 |
| |
48kHz |
46590-49190Hz |
| |
88.2kHz |
87840-90830Hz |
| |
96kHz |
93520-97530Hz |
| |
|
|
| USB supported sample rates |
44.1, 48, 88.2, 96, 176.4, 192, 352.8, 384kHz |
| Power Consumption |
| Max, High Power mode |
|
8.0W |
| Max, Low Power mode |
|
2.5W |
| Dimensions |
| 4" x 5.25" x 1.8" |
|
|
| Headphone Output Power / Low Power Mode |
Output Power mW |
|
| Load Resistance Ohms |
1 Channel Driven |
2 Channels driven |
| 4 |
80 |
22 |
| 8 |
140 |
45 |
| 16 |
310 |
90 |
| 20 |
350 |
100 |
| 32 |
600 |
175 |
| 50 |
560 |
280 |
| 300 |
83 |
83 |
| 600 |
40 |
40 |
| Headphone Output Power / High Power Mode |
Output Power mW |
|
| Load Resistance Ohms |
1 Channel Driven |
2 Channels driven |
| 4 |
925 |
240 |
| 8 |
1800 |
490 |
| 16 |
1900 |
940 |
| 20 |
1575 |
1030 |
| 32 |
1020 |
950 |
| 50 |
680 |
650 |
| 300 |
115 |
115 |
| 600 |
57 |
57 |