Altec Lansing 1715C - Manual (Page 16)

FRONT REAR-PANELS CONTROLS, SWITCHES, INDICATORS, AND CONNECTORS
Figure 14 below displays the front panel on the 1707C mixer/power amplifier with numbers that point
out each control, indicator, and switch. You can find the corresponding number and name/description
of each control, switch, or Indicator in the text below Figure 14. These controls, indicators, and
switches are identical on the
1715C.
Figure 14. Front-Panel Control, Switches, and Indicators for the 1707C
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Item Name Function/Description
1 POWER Switch Applies primary power Two-position push-push switch
for on/off mode
2 ON LED Indicator Illuminates red display on POWER switch when you
turn on power.
3 CH 1-6 Controls INPUTS
Continuously variable potentiometers graduated from
” to 0 dB. You can increase or decrease level
for each corresponding input channel. Rotate clockwise
to increase level and counterclockwise to decrease
level.
4 Green/Red Dual LED
Indicators INPUT LEVEL
Displays nominal (green) and peak (red) indication for
each channel.
5 THRESHOLD Control COMPRESSOR/LIMITER
Continuously variable potentiometer. Determines the
level at which limiting begins.
6 RELEASE TIME Control Continuously variable potentiometer. Determines the
time required for the system to return to normal after
signal falls below threshold.
7 COMPRESSION RATIO
Control Continuously variable potentiometer. Determines the
amount of limiting that will occur when the input signal
level exceeds the threshold, as set by the THRESHOLD
control.
8 ON/OFF Switch Places compressor/limiter circuit in or out of the
signal path
9 BASS Control OUTPUT
Continuously variable potentiometer. Provides boost
or cut in bass response. You can obtain normal or flat
response at a zero setting. Rotate clockwise to boost
response or counterclockwise to cut response.
10 TREBLE Control Continuously variable potentiometer. Provides boost
or cut in treble response. You can obtain normal or
flat response at a zero setting. Rotate clockwise to
boost response or counterclockwise to cut response.
11 EO IN/DEFEAT Switch Two-position switch . DEFEAT position disconnects
BASS and TREBLE controls when appropriate for
application, such as Acousta-Voicing. EQ IN connects
the BASS and TREBLE controls.
12 MASTER Level Control Continuously variable potentiometer graduated from
“ to 0 dB. Use it to simultaneously increase or de­
crease all input channels. Rotate clockwise to increase
level or counterclockwise to decrease level.
13 CLIP LED Indicator Illuminates when an internal signal overload circuit
detects high output signal levels that may cause output
clipping.
INITIAL SETUP AND OPERATION OF
MAINFRAME WITH MODULES INSTALLED
Initial Setup of an Input Module
You can buy and install the following input
modules from ALTEC LANSING:
The 1781A programmable input module. The
1781AT programmable input module with
1785A input isolation transformer, and
The 1780A and 1780AT mic/line input
modules.
To initially set up an input module, follow
these steps:
1 Rotate the input module s gain control to
the 12:00 o'clock (MID) position for plan­
ned microphone inputs or to the MIN (fully
counterclockwise) position for line-level
inputs. If the input type is unknown, rotate
the gain control to the MIN position.
2. Rotate the high-cut (HF) filter to the FLAT
position.
3. Rotate the low-cut (LF) filter to the FLAT
position.
Initial Setup of an Output Module
You can buy the 1783 line output module
from ALTEC LANSING. This module can be
installed with or without the optional
1786
output isolation transformer (also available
from Altec Lansing).
To initially set up an output module, rotate
the output module’s output level control
(labeled GAIN on the rear panel) to the MIN
position.
Initial Setup of the Mainframe
1. Rotate the MASTER output level control
on the front panel of the mainframe to the
position (fully counterclockwise).
2. Setthecompressor/limiterON/OFF switch
to the OFF position.
3. Set the tone control EQIN/DEFEAT switch
to the DEFEAT position.
Operating the 1707C/1715C Mixer/Power
Amplifiers
1. Connect a source representative of the
type of input signal to one of the input
module positions, if any. Slowly rotate the
input module's gain control clockwise un­
til the mixer/power amplifier's green LED
display ( — 10 dB) on the input-level front-
panel section fully illuminates. This is the
nominal level for providing the most effi­
cient performance and headroom.
The mixer/power amplifier's red LED dis­
play may briefly illuminate on signal
peaks. This is permissible as long as it
does not flash more than fifty percent of
the time. If it does, reduce the gain of the
input module by rotating its gain control
counterclockwise or use an external pad.
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