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TALKBACK MIC INPUT - A standard microphone input which can be used with dynamic or condenser micro-
phones. Phantom power (+48V) is available and is software controlled (see CAL mode).
CR OUT 1 and CR OUT 2 - A balanced stereo analog CR OUT 1 and CR OUT 2 outputs are provided via male XLR
connectors, which connect to your stereo monitor systems. Connections are made with standard balanced XLR
cables. These inputs are wired to the pin 1 shield, pin 2 positive pin 3 negative convention. Note: See the unbal-
anced termination wiring diagram for connecting either of these outputs to unbalanced equipment.
CUE OUTPUT - Balanced stereo CUE output is provided via male XLR connectors. Normally, this output is fed by
the CUE input signal and would typically be wired to your studio’s headphone cue system. In addition, this signal
path can double as a third speaker output in which case connection should be made to a third monitor system.
Connections are made with standard balanced XLR cables. These inputs are wired to the pin 1 shield, pin 2 posi-
tive pin 3 negative convention. Note: See the unbalanced termination wiring diagram for connecting either of
these outputs to unbalanced equipment.
FIXED DAC OUTPUT - Balanced stereo FIXED DAC output is provided via male XLR connectors. The last selected
digital input is converted and sent to this output at all times. Typically this output is used to utilize the high per-
formance m904 DAC when connected to an analog mastering deck or other analog outboard gear. Connections
are made with standard balanced XLR cables.
STEREO HEADPHONE OUTPUTS - HEADPHONE outputs are provided via ¼” TRS (Tip, Ring, Sleeve) jacks. These
outputs are wired in parallel and also run in parallel with the headphone jack on the optional remote control
unit. Connection to headphones should be made using standard ¼” TRS stereo connectors.
DIGITAL LOOP-THRU OUTPUTS (AES3, S/PDIF) - Two stereo digital loop-thru outputs are provided via AES3 male
XLR and S/PDIF RCA connectors. These provide a buffered output of a user selectable digital input. Use of high
quality 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 referencing the m904 from
an external Word Clock is not necessary for the unit to function properly as the m904 will also function quite
nicely by stripping embedded clock data from a connected digital audio source. However, you may have your
entire digital audio system referenced from a single master clock that you feel particularly good about, hence the
ability for the m904 to receive and lock itself to this clock. A high quality 75 Ohm cable should be used for Word
Clock or Superclock connections.
WORD CLOCK LOAD SWITCH - The switch labeled 1M Ohm/75 Ohm is used to terminate the Word Clock input. If
the Word Clock signal in your studio is being daisy-chained from unit to unit (including the m904), you’ll want
to set the switch to 1M Ohm, which is essentially an unloaded setting. If the m904 is the only device being clock
referenced (or the last unit in a daisy-chain of other high impedance units), you’ll want to select the 75 Ohm load
position for proper termination. NOTE: Selecting the 75 Ohm load position when there is already another device
on the line that has a 75 Ohm load will create a total load of 37 Ohms, which will attenuate the signal to a point
where the m904 will not lock.
WORD CLOCK/SUPER CLOCK THRU - This BNC connector allows you to pass the clock received at the Word Clock/
Superclock input to other digital devices downstream of the m904. The output is buffered and is designed to
drive a 75 Ohm line.
REMOTE CONNECTOR - An optional remote control unit is available for the m904. The remote provides all
controls available on the m904 front panel including a single headphone connection. Connection to the m904
optional remote control unit is provided via this HD15 connector, which carries RS422 serial data, DC power and
headphone signals. The m904 remote ships with a high quality 25’ cable. While the serial data can travel several
