744T User Guide and Technical Information
Gain (sensitivity) for inputs 3 & 4 is controlled in the setup menu. Gain resolution is in 0.1 dB incre- ments.
Analog Line Input Sensitivity
Input level sensitivity for the
While channel 1 and 2 levels can be controlled by either the menu settings or the front panel pots, channels 3 and 4 are adjusted only in the setup menu.
Signal Presence and Peak Indicator
The four signal presence and peak indicators show audio activity before
Digital Inputs – AES3
The 744T accepts AES3 (AES/EBU) balanced digital at the XLR connectors. Digital inputs are in
The front panel digital input LEDs will illuminate when digital input is selected for the indicated track(s). If the LED is flashing, digital input is selected but a no valid digital clock is received.
Digital Inputs – AES3id (S/PDIF)
The 744T accepts AES3id and S/PDIF unbalanced digital signals at the BNC connectors. The 744T will auto detect the type of digital signal and adjust accordingly. Input signals are in pairs, signals on BNC 1 appear at inputs 1 and 2, signals on BNC 2 appear at inputs 3 and 4.
AES3id inputs override analog signals present at the XLR inputs. To input analog audio while using the AES3id signal as a digital clock source, you must select analog in the input source menu selection for the appropriate inputs.
When a digital signal is present, the 744T will lock its sample rate to the source frequency. This is indicated by a highlighted block 
on the main LCD display to the right of the bit depth and sample rate indicators. Recording bit depth is not affected by the external digital source.
If you are locking the 744T to an external digital signal, be certain the source is stable. Loss of the digital signal will cause the 744T to revert to its internally set sample rate, even while recording. The portion of the file recorded after the loss of signal may not play back properly. Once recording has begun, unused digital inputs are muted, digital signals that appear on them after the record key has been pressed will not be recorded or affect the sample rate of the 744T.
The 744T will clock itself to the first digital signal presented to it. If the 744T detects a digital signal on the BNC inputs and locks to that signal, a digital signal applied to the XLR input will be ignored until the first digital signal is removed.
Input Delay
A digital delay is selectable on each channel of the 744T. Delay time per input in one microsecond (µS) steps. 1,000 microseconds equals 1 millisecond (ms). The
16
firmware v. 1.04 Features and specifications are subject to change. Visit www.sounddevices.com for the latest documentation.