Lectrosonics DA4 Operating Instructions Manual
DA4
DISTRIBUTION AMPLIFIER MODULE
OPERATING INSTRUCTIONS
and trouble-shooting guide
LECTROSONICS, INC.
Rio Rancho, NM
INTRODUCTION
TheDA4isa2widthmodule that provides the means to control and distribute an input signal to four balanced,
high-current output drivers. Each output has a separate level control. The DA4 can supply up to 20dB of gain, so
small signals can be boosted to avoid noise contamination on long cable runs.
TABLE OF CONTENTS
INTRODUCTION .......................................... 1
GENERAL TECHNICAL DESCRIPTION .......................... 2
INSTALLATION ........................................... 2
FRONT PANEL DESCRIPTION ................................ 3
REAR PANEL DESCRIPTION ................................. 3
OPERATING INSTRUCTIONS ................................. 3
SERVICE AND REPAIR ..................................... 4
RETURNING UNITS FOR REPAIR ............................. 4
SPECIFICATIONS ......................................... 5
WARRANTY ....................................... Back cover
1
GENERAL TECHNICAL DESCRIPTION
The DA4 provides an electronically balanced and RF filtered, XLR type input, and four electronically balanced and
floating, RF filtered outputs. In addition, a Through output is provided to allow the input signal to be passed through
the DA4 on to other modules.
The input stage is a unity gain differential amplifier. This stage drives the four level controls. After the level
controls, each output signal is sent to an amplifier stage with 20dB of gain. When the signals have been amplified,
they are then passed to the output drivers. The output drivers can provide ample current to drive loads as low as
600 ohms to +20dBv levels. These drivers are electronically balanced and floating, as well as RF filtered. They
provide most of the advantages of transformer coupled circuits, without the low frequency non-linearities associated
with transformers. Should transformers be desired, however, they are available as options.
10 dB BALANCED
VOLTAGE GAIN DRIVER
10 dB
VOLTAGE GAIN
10 dB
VOLTAGE GAIN
10 dB
VOLTAGE GAIN
BALANCED
DRIVER
BALANCED
DRIVER
BALANCED
DRIVER
OPTIONAL
OUTPUT
TRANSFORMER
OPTIONAL
OUTPUT
TRANSFORMER
OPTIONAL
OUTPUT
TRANSFORMER
OPTIONAL
OUTPUT
TRANSFORMER
BALANCED
OUTPUT 1
BALANCED
OUTPUT 1
BALANCED
OUTPUT 1
BALANCED
OUTPUT 1
BALANCED
INPUT
THROUGH
OUTPUT
RFI
FILTER
DIFFERENTIAL
AMPLIFIER
Figure 1 - DA4 BLOCK DIAGRAM
INSTALLATION
The DA4 module is installed from the rear of the Modular Audio Processor mainframe. The printed circuit board
can fit into any of the ten slots provided for Modular Audio Processor modules. Once the module is fit into the card
guides for the slot, it may be slid forward in the mainframe until the female edge connector seats firmly onto the
male pins of the main bus board.
Care should be taken when inserting the edge connector onto the pins to be sure there is correct alignment.
Four #2 machine screws with captive washers are provided to secure the rear panel of the LM3 to the top and
bottom rear rails of the Modular Audio Processor mainframe. Four #2 flat head screws are provided to secure the
front panel of the LM3 to the front panel of the Modular Audio Processor mainframe. Once these eight screws are
in place, the installation of this module is complete.
2
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