Sound Devices 744T, Руководство пользователя

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744T User Guide and Technical Information
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v. 2.67 Features and specifications are subject to change. Visit www.sounddevices.com for the latest documentation.
Input Setup and Control
The 744T has four inputs and four record tracks. Inputs can be analog or digital sources. Analog
inputs 1 and 2 use XLR connectors; inputs 3 and 4 use TA3 connections. Digital inputs can be either
AES3 (balanced at the XLR) or AES3id (on BNC) inputs.
One analog pair and one digital pair can be used simultaneously.
Input Source Selection
Input sources are selected in pairs, 1, 2 and 3, 4. Each input pair (1, 2 and 3, 4) accepts analog or
digital audio. The input signal type is selected using slide switch above the XLR input connector. The
setup menu has additional input control.
Manually selecting the audio source is used to force the inputs to analog while using an AES3 or
AES3id input to lock the 744T to an external sampling rate.
Digital sources connected to AES3id BNC inputs override analog signals on the correspond-
ing XLR input. The BNC input signal type is set in the menu settings
INPUT 1,2: SOURCE
and
INPUT 3,4:SOURCE
. For most situations the appropriate setting is auto select—the 744T will choose
the input type based on signal present.
The 744T is capable of off-speed sampling rates when clocked from either external digital inputs or
the word clock input.
Input sources can be set to “disabled (power save)”. This option shuts down all circuitry associ-
ated with an input pair to reduce power draw and extend battery runtime. When an input pair is
disabled, the digital input LEDs associated with the pair will slowly flash. In playback-only applica-
tions, both input pairs can be shut down to maximize power-efficiency and battery runtime.
Analog Inputs 1 and 2
Analog inputs 1 and 2, on XLR connectors, are the primary connections into the recorder. These
inputs accept balanced or unbalanced mic- or line-level inputs. When at mic-level, gain is controlled
by the front panel potentiometers. Gain for the line level inputs can be controlled by the front panel
potentiometers or menu settings. Line input gain is controlled in 0.1 dB steps.
A digital input present on the BNC inputs will override an analog signal present on the XLR inputs un-
less the input source is set to analog in the setup menu.
In the setup menu, the following functions can be controlled for analog inputs 1 and 2:
Phantom Power
Phantom power (48 volts) can be activated for inputs 1 and 2. When active, phantom is indicated by
front panel LEDs ( ).
Phantom power is available for both mic- and line-level inputs. Using line-level inputs with microphones
is useful in high SPL environments such as concert recording. Make certain to turn off phantom power
with line level output devices susceptible to damage from DC.