Thank you for your purchase of the Rolls DU30 Mic Preamp Audio Ducker. This
device temporarily and automatically mutes or "ducks" a background music signal
under an announcement. After the announcement, the music level is automatically
returned to it's previous level.
DESCRIPTION
REAR PANEL
MIC IN: Female XLR jack for connection to a dynamic or condenser paging micro-
phone.
PHTM PWR: Jumper for engaging the +12 volt phantom power to the microphone
input. The Rolls 12 volt phantom power circuit will power 99% of the world's existing
condenser microphones.
ALT IN: Stereo RCA jacks for connecting to a source different from the Mic In as the
master signal.
LINE IN: Stereo RCA jack for connection to the stereo signal source to be "ducked"
such as a tuner, CD player or cassette player.
LINE OUT: Stereo RCA jacks for connection to the system's amplifiers.
FRONT PANEL
PAD: When pressed in, the gain of the XLR Mic In is reduced by 30 dB.
MIC LEVEL: Adjusts the amount of gain in the Mic In circuit.
SENSITIVITY: The Threshold at which "ducking" begins. When the microphone level
reaches the threshold, the signal present at the Line Ins jacks is reduced until the
announcement is over, then the Line In signal returns to its previous level.
OPERATION
Shown below is a diagram of typical connection for the DU30. Set the level of the
music signal for a comfortable level. Speak into the microphone and adjust the Mic
Level for a comfortable level, then adjust the Sensitivity so that the music is muted
when speaking with a normal voice.
SPECIFICATIONS
Frequency Response
20 Hz - 40 kHz
Input Impedance
100K
W
unbalanced, 600
W
balanced
THD + Noise
<0.03% typical
Noise Floor
-78 dB
Indicators
Power LED
Active LED
Input/Output jacks
XLR balanced output
RCA unbalanced input and output
Size:
4" x 4" x 1.5"
Weight:
1 lb. (.5 kg)
Power:
12 - 16 VDC 50mA
5 x 1.2 mm DC Jack - Center Negative
SCHEMATIC
TUNE +
TUNE -
SET
PRESET
FM / AM
STEREO
/MONO
MUTE
STATION CALL
2 / 10
5 / 13
1 / 9
6 / 14 7 / 15
3 / 11 4 / 12
8 / 16
FREQUENCY
PRESET
SIGNAL
HEADPHONE
VOLUME
HEADPHONE
OUT
ST
FM
MW
MUTE
MHz
kHz
AUTO
RS79
0 10
Paging Amplifier
phan
pwr
12 VDC
PAD
SENSITIVITY
MIC
LEVEL
PWR
DU30
+
-
INPUT
INPUT
INPUT
MIC
AUX
LINE
OUTPUT
AUDIO DUCKER
Mic
Preamp
1
27-Sep-2001
Date:
Rev:
Sheet 1 of
Size:
Ba
+V
I N
+V
VB
VB
VB
VB
VB
VB
VB
+V
+V
L I N E I N
D U C K L I N E I N
M I C I N
L I N E O U T
+V
M I C V O L
2
3
1
4
L M 3 5 8
2
3
1
4
U 1 A
4 5 6 0
2
3
1
J 4
J A P D C
6
5
7
8
U 2 B
4 5 6 0
D 2
L D S G
4
5
6
S W
1 B
D P D T
1
2
3
S W
1 A
D P D T
D 1
1 N 4 0 0 1
6
5
7
8
U 3 B
L M 3 5 8
P 2
P 1 0 0 K
2
3
1
4
U 2 A
4 5 6 0
P 1
P 1 0 0 K
6
5
7
8
U 1 B
4 5 6 0
1
2
3
J 1
X L R F P C
1
3
J 2 A
R C A X 4
2
7
J 2 B
R C A X 4
4
6
J 2 C
R C A X 4
5
8
J 2 D
R C A X 4
1
3
R C A X 2
2
3
R C A X 2
1
J P 1 A
H D 2
2
J P 1 B
H D 2
R 1
4 . 7 K
R 2
4 . 7 K
R 3
2 2 K
R 4
2 2 K
R 5
1 K
R 6
1 K
R 7
2 2 K
R 8
2 2 K
R 9
2 2 K
1 K
R 1 2
4 7 K
R 1 4
4 7 K
R 1 5
4 7 K
R 1 6
4 7 K
R 1 7
4 7 K
R 2 1
3 3 K
R 2 2
1 0 K
R 2 3
3 3 K
R 2 4
1 0 K
R 2 5
1 M
R 2 7
4 7 K
R 2 8
1 0 0 K
R 3 1
1 K
R 3 0
1 K
R 3 2
4 7
R 3 3
4 . 7 K
R 3 4
4 7 K
R 3 5
4 7 K
C 1 5
5 0 3
C 1 8
4 7 U
D 3
1 N 4 1 4 8
D 6
1 N 4 1 4 8
C 3
2 5 P F
C 4
2 5 P F
C 5
1 0 U
C 6
1 0 U
C 9
1 2 0 P F
C 7
1 U
C 8
1 U
C 1 0
1 0 U
C 1 1
1 U
C 1 3
1 U
C 1 4
1 0 U
C 1 9
1 2 0 P F
R 1 3
4 7 K
R 1 8
4 7 K
R 1 9
1 0 0 K
C 1 6
1 K U F
C 1
1 0 U F 1 6 V N P
C 2
1 0 U F 1 6 V N P
Q 1
J 1 1 3
Q 2
J 1 1 3
D 4
1 N 4 1 4 8
D 5
1 N 4 1 4 8
C 1 2
5 0 3
VB
C 1 7
5 0 3
R 2 0
1 0 0 K
R 2 6
1 0 0 K
Q 3
2 N 3 9 0 6
+V
R 2 9
4 7 K
A L L R E S I N S Q U I D S
A L L C A P S I N Z E R G S
F I G H T A C O L D B U Y R O L L S
1 2 - 1 6 V D C
J 3 B
J 3 A
U 3 B
S E N S I T I V I T Y
R 1 1
R 1 0
2 2 K
R O L L S C O R P O R A T I O N
5 9 6 8 S o u t h 3 5 0 W
e s t
S a l t L a k e C i t y , U T 8 4 1 0 7
T i t l e : D U C K E R D U 3 0
D o c u m e n t N u m b e r :
D U 3 0 . S C H
A
