Sound Devices 744T - Manual (Page 65)

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• Power on unit – unit will turn on and be ready for operation.
• Power on and begin recording – unit will power on and begin recording with the settings
used when previously powered down.
• Power on, power off unit – external DC functions as the on/off switch.
• Power on and begin recording, power off – unit will power and begin recording, then turn off
when power is removed.
These functions are useful when the unit is part of a production kit powered by a single power
source. A single power switch can be used to power on the whole kit.
In addition to the internal record timer, the auto functions (power on/begin record/power off) can
be used for more extensive unattended recording control. Using an outboard timer attached to a
DC supply the 744T can be placed and activated to record events including EFX or nature, and for
surveillance applications.
Pin-3 (+) of the external DC input must be wired in order for the External Power Functions to operate.
Power-up Messages
This Setup Menu option provides a choice of whether or not the 7-Series displays messages upon
boot up. It is best practice to set POWER: POWER-UP MESSAGES to disabled when using the exter-
nal power functions to activate recording. This prevents power up messages, such as daily folder
prompts, output attenuation notices, and time and date setting notices, from prohibiting the 7-Series
from beginning a recording
Power Consumption Variables
The 744T draws power from either its on-board Li-ion battery or from external DC sources. Two
factors need to be considered to calculate battery runtime—battery/power supply capacity and unit
power consumption. The best determination of your run time is to experiment with a given record-
ing setup.
The 744T power consumption varies over a range between 4 W to 20 W (12 volts), depending on ac-
tive functions. The following functions have the most significant affect on power consumption:
Inputs Active analog inputs increase power consumption. If recording from digital sources, dis-
able analog inputs, or inputs altogether to reduce power consumption. If recording solely to
inputs 1 and 2, disable inputs 3 and 4 to reduce power consumption. Analog inputs and the
microphone preamps draw current whether they are idle or active. Active inputs draw 1.5 W
compared to deactivated inputs.
Hard Drive Activity When the unit is recording to or playing back from the internal hard drive, power consumption
raises by approximately 2 W.
Microphone Powering Phantom powered microphones draw power for operation. Up to 1 W can be drawn from the
phantom supply.
Battery Chargers Depending on the charge state of the on-board Li-ion and the internal AA time code battery,
the charging circuit can draw ~10 W from external DC.
Sampling Rate The 744T draws more power at higher sampling rates. Each doubling of the sampling rate
adds ~1 W of power consumption.