Professional monitoring with every feature you could ask for.

The Grace Designs M904 Stereo Monitor Controller combines multiple balanced and unbalanced analog and digital inputs with precision level controls for two pairs of studio monitors and dual headphone outs. s-Lock phase lock loop word clock regeneration for ultralow jitter and rock solid digital stability. Rackmount. Software updates with a host of new features are now available from the Grace Design website for the m904. Downloading these requires a special cable which, if you do not have, is available free of charge from Grace Design by contacting their Boulder office. If you do not have internet access, the downloads will be provided to you on CD, also free of charge.

Grace Design m904 Stereo Monitor Controller Features:

Multiple stereo analog inputs
24-bit/192kHz digital stereo inputs — AES3, S/PDIF, ADAT, and TOSLINK
s-Lock phase lock loop word clock regeneration for ultralow jitter and rock solid digital stability
Precision main and headphone level controls with a 100dB range in 0.5 dB steps
All controls on front panel with an optional m906 style remote control unit available
Multiple speaker set selection
High current audiophile headphone amplifier built in with two outputs on front panel
Complete system level calibration (inputs, outputs, inter-channel balance, dim)
Balanced talkback microphone input and activation switch with additional external foot switch control jack
Fixed level stereo DAC output for direct digital transfers

Grace Design m904 Stereo Monitor Controller Specifications:

ANALOG INPUT

THD+N @ 0dB gain, 1kHz
+20dBu out
<0.001% (0.00075% typical)
+10dBu out
<0.003% (0.001% typical)
0dBu out
<0.009% (0.005% typical)
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Intermodulation Distortion SMTPE/DIN 4:1 50Hz, 7kHz
@+20dBu out
<0.002% (0.0015% typical)
@ 0dBu out
<0.008% (0.006% typical)
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Frequency Response
+/-3dB
3Hz - 250Khz
ÿ

Dynamic Range
20-22kHz bandwidth
112dB
20-22kHz bandwidth and A weighting filter
115dB
ÿ
Output Noise
20-22kHz bandwidth, -20dB gain
ÿ
High gain mode
-89dBu
Low gain mode
-98dBu
20-22kHz bandwidth and A weighting filter, -20dB gain
ÿ
High gain mode
-91dBu
Low gain mode
-99dBu
ÿ

Phase Deviation
20Hz to 20kHz
< 4ø
10Hz to 100kHz
< 15ø
ÿ

Crosstalk any channel
100Hz
< 100dB
1kHz
< 100dB
20kHz
< 85dB
ÿ

Balanced Input CMRR
60Hz
> 65dB
1kHz
>65dB
10kHz
>60dB
ÿ

Gain Range
Low gain mode (0.5dB steps)
-105.5dB to +20dB
High gain mode (0.5dB steps)
-95.5dB to +30dB
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Channel Tracking Accuracy
Any channel
+/-0.05dB
ÿ

Maximum Output Level
Low gain mode (balanced)
+15dBu
High gain mode (balanced)
+27dBu
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Maximum Input Level
Balanced inputs
+30dBu
Unbalanced inputs
+20dBu
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Impedances
Balanced inputs
30k Ohms
Unbalanced inputs
50k Ohms
Balanced outputs
300 Ohms
Minimum load impedance
300 Ohms
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DIGITAL TO ANALOG CONVERTER FIXED OUTPUTS

Output Levels
ÿ
User selectable (0dBFS)
+16dBu / +24dBu
Fixed output trim range (0.5dB steps)
-95.5dB to +30dB
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THD+N
1kHz, -1dBFS, 20-22kHz bandwidth (44.1kHz)
0.0015%
ÿ

Dynamic Range
20-22kHz bandwidth
>111dB
ÿ

Input Lock Range
AES3/SPDIF
32kHz to 192kHz
TOSLINK
32kHz to 96kHz
ADAT LIGHTPIPE
30kHz 55kHz
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s-Lock Sample Clock Intrinsic Jitter
20-22kHz bandwidth
<25ps
ÿ

s-Lock Sample Clock Jitter Rejection
1kHz sine jitter
-40dB
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s-Lock Supported Sample Rates
AES3, SPDIF
44.1, 48, 88.2, 96, 176.4, 192kHz
TOSLINK
44.1, 48, 88.2, 96kHz
ADAT LIGHTPIPE
44.1, 48kHz
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s-Lock Capture Range
44.1, 48kHz
+/- 10Hz
88.2, 96kHz
+/- 20Hz
176.4, 192kHz
+/- 40Hz
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Word Clock / Superclock Inputÿ
Impedance (switchable)
75 Ohms / 1M Ohms
Minimum Voltage
3V peak to peak
Maximum Voltage
5V peak to peak
Word clock frequencies supported
44.1, 48, 88.2, 96, 176.4, 192kHz
Superclock frequencies supported
11.2896MHz, 12.288MHz (256x fs)
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POWER SUPPLY / MECHANICAL SPECS

Power consumption
40W
Input Voltage 50-60Hz
100, 120, 220, 230-240VAC
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Dimensions
Main chassis IEC 2U
3.5" x 10.5" x 17"
Remot control unit
1.6" x 8" x 5.25"
Power supply unit
1.7" x 8.5" x 8.5"
ÿ

Weight
Main chassis
14.1lbs / 6.4kg
Remote control unit
2.3lbs / 1kg
Power supply unit
6.5lbs / 2.9kg