Grace m904 Owner'S Manual Download Page 26

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cleanIng and maIntenance

Your m904 system chassis is constructed out of high quality stainless steel. Under normal circumstances, virtually

no maintenance is required to keep the unit looking shiny and new. However, if you unit becomes smudged or

dirty, here are some cleaning tips: We recommend using either Pledge furniture polish or stainless steel cleaner

(availble at your local hardware store). Apply cleaner to a clean, dry, lint free cloth and gently wipe all stainless

surfaces, taking care not to allow the cleaning product to build up around the panel switches or knobs.

cable and connector WIrIng dIagramS

PIN 1 headphone left
PIN 2 headphone right
PIN 3 +8VDC
PIN 4 RX-
PIN 5 TX+

HD15 remote cable connector

PIN 6 headphone left
PIN 7 headphone left
PIN 8 (NC)
PIN 9 RX+
PIN 10 TX

PIN 11 analog ground
PIN 12 analog ground
PIN 13 digital ground
PIN 14 digital ground
PIN 15 digital ground

BLACK

RED

BLACK

RED

BLACK

ORANGE

BROWN

YELLOW

BLACK

BROWN

ORANGE

YELLOW

END 1

END 2

HD15 remote cable diagram

SHIELD

HOT

GND

TIP

SLEEVE

m906 end

Normally open switch

Talkback remote switch diagram

SHIELD

HOT

GND

(OPEN)

unbalanced output termination

pin 1> gnd

pin 2 > (+)

pin 3 > (-)

XLR connector pinout

Summary of Contents for m904

Page 1: ...owner s manual all contents Grace Design Lunatec LLC manual Rev H m904 firmware Rev 1 04 m904 RCU firmware Rev 1 05 ...

Page 2: ...chnical documents Grace Design has been building audiophile quality products for the recording industry for over a decade The technology developed for the m904 and all of our products has evolved through a process of extensive listen ing field testing and careful refinement Your new m904 system represents a combination of absolutely pristine audio performance robust mechanical construction and bom...

Page 3: ...nd transportation temperature range 40 C to 70 C Maximum altitude 3000m 9843 ft Equipment suitable for continuous operation Weight 16 3lbs 7 4kg Safety Marking Symbols CAUTION READ ACCOMPANYING DOCUMENTS This symbol located on the equipment and in this manual refers to important instruc tions Read this manual thoroughly before operating this equipment WARNING ELECTRICAL SHOCK HAZARD This symbol lo...

Page 4: ... gain range in 0 5dB steps Front panel user interface provides the user with instant feedback of operational parameters in addition to immediate access to all controls Optional remote control unit provides full control function in an elegant convenient desktop unit Multiple speaker set selection up to three stereo sets High current reference headphone amplifier built in with two outputs available ...

Page 5: ...ed with each speaker set 1 or 2 I MAIN LEVEL EDIT ROTARY ENCODER This stepped rotary encoder controls the main speaker output levels in 5dB increments This encoder is also used to adjust level offset calibration values when in CAL mode Additionally double clicking the encoder recalls the stored level preset J HEADPHONE LEVEL ROTARY ENCODER This stepped rotary encoder controls the headphone output ...

Page 6: ...LOCK LOAD TERMINATION SWITCH F ADAT INPUT G AES3 2 STEREO INPUT H AES3 1 STEREO INPUT I S PDIF STEREO INPUT J TOSLINK STEREO INPUT K UNBALANCED ANALOG INPUTS L TALKBACK MIC INPUT M BALANCED 2 INPUTS N BALANCED 1 INPUTS O BALANCED CUE INPUT P BALANCED CUE OUTPUT Q CONTROL ROOM SPEAKER OUT 2 R CONTROL ROOM SPEAKER OUT 1 S FIXED DAC OUTPUT AES3 T TALKBACK REMOTE SWITCH JACK U REMOTE CONTROL CONNECTOR...

Page 7: ...ADPHONE LEVEL ROTARY ENCODER This stepped rotary encoder controls the headphone output level in 5dB increments Double clicking the encoder alternately mutes and recalls the stored level preset E MAIN LEVEL EDIT DISPLAY This blue 3 digit main level edit display shows the current relative main speaker output level values based on the position of the main level rotary encoder The range of this displa...

Page 8: ...L switch will flash CAL mode is exited by pressing the switch again Please refer to the Accessing the Cal Modes chapter of this manual for detailed information about m904 system calibration M MON CUE SWITCH The MON CUE switch is an illuminated switch used for routing the selected stereo input source to the CUE output In addition this switch may be configured to access a third stereo speaker pair o...

Page 9: ...factory REGISTER YOUR UNIT Also we strongly urge you to register your unit with grace design We provide a limited 5 year warranty on all of our products but if you don t register your system it s hard for us to help you if and when help becomes neces sary So please take a few minutes to complete the enclosed warranty registration card and mail it in or simply go to the warranty registration form o...

Page 10: ...m and then power down the m904 It should also be noted that while the power sequence will not damage headphones connected to the m904 you should NOT be wearing them when power is applied or turned off System Connections The input output interface connections highlighted earlier in this manual are detailed below Pinout diagrams are located in the cable and connector wiring diagrams page 32 section ...

Page 11: ...uality 110 Ohm balanced cable for the AES3 out 75 Ohm cable for the S PDIF out is highly recommended WORDCLOCK SUPERCLOCK IN The m904 can accept a Word Clock Superclock or Loop Sync signal from an ex ternal clock generating unit via this BNC connector This might be a stand alone clock source or via for example the Word Clock output from your digital audio workstation It should be noted that refere...

Page 12: ...a time NOTE While the CONTROL ROOM SPEAKER and HEADPHONE outputs follow any input selection changes the FIXED DAC OUTPUTS are always fed from the last selected digital input source Analog Inputs The m904 provides the following analog input sources BAL1 BAL2 UNBAL and CUE To select an analog input simply press the corresponding input switch BAL1 BAL2 UNBAL or CUE Once pressed the selected input wil...

Page 13: ...clock from a digital audio stream From our point of view it matters little as our s Locktm PLL Phase Lock Loop will automatically be applied once it detects the incoming clock source more about s Lock below The SEL switch located left of the SYSTEM LCD window is used to select the clock source you d like to use as a reference for the m904 system The LCD will show the currently selected source If y...

Page 14: ...de is now active 1 Press the MON CUE switch The LCD display will indicate whether you are in MON CUE mode or in Speaker 3 2 mode see screenshots 3 4 cue mode global level screenshot 3 speaker 3 mode global offset screenshot 4 Repeatedly pressing the MON CUE switch steps through the following settings CUE OUTPUT LEVEL 3 GLOBAL CUE OFFSET LEFT CHANNEL CUE OFFSET RIGHT CHANNEL SPEAKER 3 OFFSET GLOBAL...

Page 15: ...ed as left channel to Tip right channel to Ring and ground to Sleeve In addition there is a headphone jack on the rear of the optional remote control unit All are active simultaneously The m904 headphone amplifier is based on our m902 reference headphone amplifier technology Headphone Output MUTING Recalling the Headphone Output Level Preset The HEADPHONE level encoder switch is used for two funct...

Page 16: ...en the dim switch is pressed dim mode becomes active and the switch LED lights solid When pressed again dim is exited and the switch LED is extinguished Using the Talkback Feature The m904 provides a balanced talkback microphone input on the rear panel via a female XLR connector Af ter you ve plugged in a talkback mic you can set the gain for the mic preamp turn on 48v phantom power if needed and ...

Page 17: ...ghout this manuaul is located in the upper right hand corner of the re mote unit and is used to display various system messages and text describing the current operating mode of the m904 It has been designed to provide you with a clear display of vital system information in dimly lit environ ments and its off axis viewing angle is superb Typical LCD window showing the digital input selected and DA...

Page 18: ...led the next time you power up your system System parameter values can also be reset to the factory defaults at any time via a sequence outlined at the end of this section Calibrating Input Source Levels Every m904 source input both analog and digital can be calibrated to offset any level differences that may exist between different sources The relative range of calibration is 10dB in 0 5dB steps ...

Page 19: ...de The menu is 3 stepped as follows TOSLINK INPUT OFFSET ADAT INPUT OFFSET ADAT SOURCE PAIR SELECT Once in ADAT INPUT OFFSET MODE pressing the OPTICAL input switch one more time will bring up the ADAT 4 SOURCE PAIR SELECT menu Simply use the main edit rotary encoder to choose the desired input source pair which will be displayed in the main level display Press the CAL switch to exit CAL mode and r...

Page 20: ...owing Enter CAL mode by pressing the CAL switch The switch LED will begin to flash indicating that you re now in 1 calibration mode Press the MON CUE switch The LCD display will indicate whether you are in MON CUE mode screenshot 11 2 or in Speaker 3 mode screenshot 12 cue mode screenshot 11 speaker 3 mode screenshot 12 Repeatedly pressing the MON CUE switch steps through the following settings 3 ...

Page 21: ... mode and return to the normal operating state by pressing the flashing CAL switch 11 Setting the Fixed Level DAC Outputs The DAC outputs are great to use when you need to make transfers to other machines or for mixing or master ing purposes The LEFT and RIGHT FIXED DAC outputs can be adjusted individually in CAL mode The absolute range of calibration is from 96dB to 31 5dB in 0 5dB steps Note tha...

Page 22: ...atisfied with the new digital loop through source you can select a new function to edit or exit CAL 6 mode Exit CAL mode and return to the normal operating state by pressing the flashing CAL switch 7 Changing 7 Segment Display Brightness The two 7 Segment displays on the m904 can be adjusted in brightness to match the working environment This is adjusted as follows Enter CAL mode by pressing the C...

Page 23: ...egin to flash indicating that you re now in cali 1 bration mode Press the HEADPHONE encoder switch twice 2 The LCD display will read HEADPHONE OUTPUT LEVEL PRESET 3 CAL will be displayed in the headphone level LED display while the current preset level will be shown in the MAIN 4 LEVEL 7 segment display The headphone output will be updated to the preset level Rotate the main level edit rotary enco...

Page 24: ...r output will dim The LCD will read DIM ATTEN LEVEL screenshot 19 dim level adjust screenshot 19 To increase the dim dB value rotate the main level encoder in a counter clockwise direction As you do this you ll 3 see the dim settings change in 5dB increments Rotate the encoder in a clockwise direction to reduce the dim level Once you re satisfied with the new dim setting you can select a new funct...

Page 25: ...terface When the RCU is activated the m904 frontpanel LCD screen will read remote control activated and all local controls will be inactive and all illuminat ed switches will extinguish The user may select between remote and local control while the system in powered up and active Note For customers who purchase a m904b system with a m904RCU this switch is not present and the m904 RCU port is alway...

Page 26: ...itches or knobs Cable and Connector Wiring Diagrams 1 6 11 5 15 2 3 4 7 8 9 10 12 13 14 PIN 1 headphone left PIN 2 headphone right PIN 3 8VDC PIN 4 RX PIN 5 TX HD15 remote cable connector PIN 6 headphone left PIN 7 headphone left PIN 8 NC PIN 9 RX PIN 10 TX PIN 11 analog ground PIN 12 analog ground PIN 13 digital ground PIN 14 digital ground PIN 15 digital ground 1 6 11 5 15 2 3 4 7 8 9 10 12 13 1...

Page 27: ...MPLIFIER TALKBACK MIC TOSLINK WORDCLOCK SUPERCLOCK IN WORDCLOCK SUPERCLOCK INPUT SELECTORS DIM MONO L R CAL SPEAKER SELECT DAC AES3 RX s Lock PLL TALKBACK GAIN DAC OUTPUT 6 CHANNEL CUE SPEAKER 3 TALKBACK MIC PREAMP CUE INPUT AMP UNBALANCED INPUT AMPS BALANCED OUTPUT DRIVERS OUTPUT DRIVERS BALANCED MON TO CUE BALANCED OUTPUT DRIVERS 2 CHANNEL WORD CLOCK PLL LEVEL CONTROL LEVEL CONTROL LEVEL CONTROL...

Page 28: ...91dBu Low gain mode 99dBu Phase Deviation 20Hz to 20kHz 4 10Hz to 100kHz 15 Crosstalk any channel 100Hz 100dB 1kHz 100dB 20kHz 85dB Balanced Input CMRR 60Hz 60dB 1kHz 65dB 10kHz 60dB Gain Range Low gain mode 0 5dB steps 105 5dB to 20dB High gain mode 0 5dB steps 95 5dB to 30dB Channel Tracking Accuracy Any channel 0 05dB Maximum Output Level Low gain mode balanced 15dBu High gain mode balanced 27d...

Page 29: ...z TOSLINK 44 1 48 88 2 96kHz ADAT LIGHTPIPE 44 1 48kHz s Lock Capture Range 44 1 48kHz 10Hz 88 2 96kHz 20Hz 176 4 192kHz 40Hz Word Clock Superclock Input 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 POWER SUPPLY GENERAL ...

Page 30: ...ortant that you mail the completed warranty registration card enclosed with all of our products within 10 days of the original date of purchase You may also register your product directly with Grace Design by telephone 303 443 7454 Monday Friday 9 00am to 5 00pm MST or you can register your product online at www gracedesign com This warranty is in lieu of all other warranties whether written expre...

Page 31: ...oltage and fuse information in Table 1 06 28 2007 edg D 34 Added headphone output impedance to spec table 06 28 2007 edg D 35 Changed power consumption and weight specs 06 28 2007 edg D 36 Added Revision table 06 28 2007 edg E 19 Added TB latching information 02 01 2008 edg F all Updated format 11 24 08 edg G 1 Changed Main Unit firmware to Rev 1 04 02 27 2009 edg H 10 Changed fuse values to inclu...

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