Rear Panel Description; Am8 Rear Panel - Lectrosonics AM8 Instruction Manual

AM8

Rear Panel Description

MIC/LINE INPUTS 1-8 - Accepts balanced or unbal-
anced signal. Fully balanced differential input, RF
filtered.
DIR OUT - Provides a line level signal from each indi-
vidual channel. The direct output is a post-VCA signal.
Any attenuation from the auto mixing process, compres-
sor/leveler system or remote attenuation will be reflect-
ed in the direct out signal. This provides versatility for
different mixing applications such as distributed over-
head speaker systems. This 100 Ohm output provides
a +20dBu max signal into a high impedance load.
Note: The DIR OUT shares a ground with the
MAIN OUT.
Don't use the CHANNEL IN grounds for the DIR
OUT!
When connecting to other equipment, the ground
connection of the MAIN OUT will also be adequate
for all the direct outputs. A separate ground
connection is not needed for each direct out.
FUNCTION SELECTION SWITCHES 1-8 - Allow vari-
ous functions of the input channels to be set.
Dip switch 1 chooses the channel mode. Auto mode
(down position) sets operation to automatic, with chan-
nel gain determined by its signal level relative to other
microphones. When a channel is set to Direct, its signal
will affect the levels of other channels set to Auto, but it
will not be affected by other channels (no NOM attenua-
tion will occur on a channel set to Direct). Note, how-
ever, that the Remote Level control feature functions
regardless of the setting of the Auto/Direct mode switch.

AM8 Rear Panel

PWR
IN
EXPANSION
(CH40)
M
OUT IN LecNet
A S
S L
20 VAC (RS232)
T A
E V
R E
6
LECTROSONICS, INC.
CH MODE
MAIN OUT
REMOTE LEVEL
+ –
CONTROL
CH8 IN
DIR
+ –
1 2 3 4
OUT
Dip switch 2 turns +15V phantom power on (down posi-
tion) or off (up position).
Dip switches 3 and 4 set the gain of the input pream-
plifier. 0dB gain, for line level sources, is set when
switches 3 and 4 are in the up position. 30dB gain, typi-
cally for high output (electret) microphones, is set when
switch 3 is in the up position and switch 4 is in the down
position. 50dB gain, used for low output (dynamic)
microphones, is set when both switches are in the down
position.
MAIN OUT - Provides a balanced system output. The
Main Out may also be used in an unbalanced mode by
connecting the "+" terminal of the Main Out to the signal
lead of the unbalanced device, and the ground terminal
of the Main Out to the ground of the unbalanced device.
Do not connect the "-" terminal of the Main Out.
REMOTE LEVEL CONTROL - Allows remote control
of both channel levels and the master level. Either 10K
ohm linear pots or an adjustable DC control voltage
may be used. The volume control action is internally
audio scaled in software. This gives an "audio-taper"
characteristic to a linear pot. Approximately 15dB of
attenuation happens for the first half of pot rotation, with
the rest of the attenuation (to full off) happening in the
second half of pot rotation. When using a DC control
voltage, the control constant is .167V/dB (or 6dB/V)
from 0V to 5V. At 5V, the channel is turned completely
off. The control voltage should not exceed 5V. Below is
a listing of the 15 pins on the Remote Level control port
and their functions.
DIRECT OFF
AUTO ON
1 2 3 4 3 4
PHANTOM 0dB GAIN (LINE) +30dB GAIN (ELECTRET) +50dB GAIN (DYNAMIC)
CH7 IN CH6 IN CH5 IN
DIR DIR
+ – + – + –
1 2 3 4 1 2 3 4 1 2 3 4
OUT OUT
3 4
CH4 IN CH3 IN CH2 IN
DIR DIR DIR
+ – + –
1 2 3 4 1 2 3 4 1 2 3 4
OUT OUT OUT
LECTROSONICS, INC.
US PATENT NUMBER 5,414,776
CH1 IN
DIR DIR
+ – + –
1 2 3 4
OUT OUT