Rolls Car Amplifier DU30 User Guide

LIMITED WARRANTY  
This product is warranted to the original consumer purchaser to  
be free from defects in materials and workmanship under normal installa-  
tion, use and service for a period of one (1) year from the date of purchase  
as shown on the purchaser’s receipt.  
The obligation of Rolls Corporation under this warranty shall be  
limited to repair or replacement (at our option), during the warranty period  
of any part which proves defective in material or workmanship under nor-  
mal installation, use and service, provided the product is returned to Rolls  
Corporation, TRANSPORTATION CHARGES PREPAID. Products returned  
to us or to an authorized Service Center must be accompanied by a copy of  
DU30 MIC PRE - DUCKER  
Automatically ducks music under announcements  
• Perfect for restaurants and small clubs  
the purchase receipt. In the absence of such purchase receipt, the warranty • Clean, Quiet Mic Preamp  
period shall be one (1) year from the date of manufacture.  
This warranty shall be invalid if the product is damaged as a  
The DU30 is a microphone preamp and back-  
result of defacement, misuse, abuse, neglect, accident, destruction or alter-  
ation of the serial number, improper electrical voltages or currents, repair,  
alteration or maintenance by any person or party other than our own service  
facility or an authorized Service Center, or any use violative of instructions  
furnished by us.  
This one-year warranty is in lieu of all expressed warranties, ob-  
ligations or liabilities. ANY IMPLIED WARRANTIES, OBLIGATIONS,  
OR LIABILITIES, INCLUDING BUT NOT LIMITED TO THE IMPLIED  
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PAR-  
TICULAR PURPOSE, SHALL BE LIMITED IN DURATION TO THE ONE  
YEAR DURATION OF THIS WRITTEN LIMITED WARRANTY. Some  
states do not allow limitations on how long an implied warranty lasts, so  
the above limitation may not apply to you.  
ground music preamp. When an announcement is  
made into the microphone, the music is automati-  
cally "ducked" under the announcement. Then the  
music is brought back to it's previous l level.  
IN NO EVENT SHALL WE BE LIABLE FOR ANY SPECIAL,  
INCIDENTAL OR CONSEQUENTIAL DAMAGES FOR BREACH OF  
THIS OR ANY OTHER WARRANTY, EXPRESSED OR IMPLIED,  
WHATSOEVER. Some states do not allow the exclusion or limitation of  
special, incidental or consequential damages so the above limitation or ex-  
clusion may not apply to you. This warranty gives you specific legal rights,  
and you may also have other rights which vary from state to state.  
Rolls Corporation  
Salt Lake City, UT  
9/01  
 
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.  
SPECIFICATIONS  
Frequency Response 20 Hz - 40 kHz  
Input Impedance  
THD + Noise  
Noise Floor  
Indicators  
100KW unbalanced, 600 W balanced  
<0.03% typical  
-78 dB  
Power LED  
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.  
Active LED  
Input/Output jacks  
XLR balanced output  
RCA unbalanced input and output  
4" x 4" x 1.5"  
Size:  
Weight:  
Power:  
1 lb. (.5 kg)  
12 - 16 VDC 50mA  
5 x 1.2 mm DC Jack - Center Negative  
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.  
SCHEMATIC  
C
3
+V  
S
D
W
1
A
J
P
1
A
K
1
2
2
5
P
H
H
D
D
2
2
P
D
T
S
E
N
S
I
T
I
V
I
T
Y
3
1
R
8
OPERATION  
2
2
K
J
P
1
B
2
P
P
1
2
0
0
K
R
2
1
0
R
2
4
.
7
K
R
1
1
2
K
R
1
5
+V  
R
1
R
R
3
4
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.  
C
1
K
4
.
7
2
2
K
C
4
R
9
1
K
+V  
4
5
6
0
1
N
D
4
3
1
4
8
6
5
+V  
2
5
P
2
2
K
L
M
3
5
8
1
C
0
U
1
6
V
N
P
7
2
3
U
1
B
C
6
R
1
2
6
3
1
L
M
3
5
8
U
3
B
0
0
K
2
6
5
C
5
1
0
U
Q
3
1
0
U
1
6
V
N
P
R
1
6
7
U
3
B
2
N
3
9
0
6
J
1
2
2
K
K
R
7
R
2
0
VB  
1
0
U
D
6
1
2
2
K
1
0
0
K
X
L
R
P
C
4
6
1
N
4
4
8
5
VB  
VB  
S
W
1
B
M
I
C
I
N
D
P
D
T
M
I
C
V
O
L
P
1
STAT
STEREO  
HEADPHONE  
VOLUME  
P
1
0
0
K
1
5
/
/
9
2
/
10  
2 /MONOFM AMTUNE +  
/
HEADPHONE  
OUT  
ST AUTO  
FM  
MUTE  
MHz  
kHz  
VB  
SIGNAL  
C
9
MW  
D
U
C
K
L
I
N
E
I
N
1
2
R
0
P
FREQUENCY  
PRESET  
0
10  
RS79  
SET  
C
1
0
13  
6
/
1
6 MUTE  
TUNE -  
PRESET  
I
N
R
4
1
6
R
R
C
C
A
A
X
X
2
2
1
0
U
J
3
A
7
K
1
8
R
1
2
R
C
A
X
4
C
7
1
4
7
K
J
2
A
1
U
4
7
K
R
1
3
0
1
2
+V  
L
I
N
E
O
U
T
K
R
1
3
4
7
K
R
1
9
4
5
6
0
6
5
R
J
C
A
X
4
R
4
1
4
7
1
0
0
K
U
2
B
J
3
B
2
B
7
K
2
4
5
6
0
VB  
C
5
1
5
R
1
7
R
1
5
VB  
R
1
3
1
C
8
2
3
0
3
R
7
3
4
C
1
8
R
3
5
4
7
K
4
7
K
K
12VDC  
1
U
1
4
K
U
1
A
4
7
U
4
7
K
MIC  
INPUT  
phan  
AUX  
INPUT  
LINE  
OUTPUT  
+
-
R
3
2
INPUT  
+V  
4
7
1
2
-
1
6
V
D
C
pwr  
2
3
1
C
R
1
2
9
7
L
I
N
E
I
N
1
2
0
P
C
1
1
6
D
1
R
J
C
C
A
A
X
X
4
4
J
4
C
1 4  
U
K
U
R
4
3
3
R
1
2
2
2
2
C
D
R
2
1
C
1
1
1
1
N
4
0
0
1
1
0
.
7
K
0
K
J
A
P
D
C
4
5
D
4
Paging Amplifier  
C
5
1
7
D
2
1
D
N
4
1
4
8
0
3
3
3
K
U
L
D
S
G
4
7
K
Q
1
2
J
J
1
1
1
1
3
3
5
4
5
6
0
VB  
R
2
8
Mic  
Preamp  
AUDIO DUCKER  
1
N
4
1
4
8
2
R
J
1
Q
U
2
A
3
1
0
0
K
R
O
L
L
S
C
O
R
P
3
,
O
R
A
T
I
O
N
DU30  
A
A
L
L
L
L
R
C
E
A
S
P
I
N
S
Q
Z
U
I
D
S
5
9
t
6
L
8
a
S
o
u
t
i
h
5
0
W
e
4
s
1
t
S
I
N
E
R
G
S
R
3
2
3
R
2
4
VB  
S
a
l
k
e
C
t
y
U
T
8
0
7
C
1
3
1
0
K
I
G
H
T
A
C
O
L
D
B
U
Y
R
O
L
L
S
3
K
T
i
t
l
e
:
D
U
C
K
E
R
D
U
3
0
1
U
C
5
1
2
R
1
2
5
R
4
2
9
D
o
c
u
m
e
n
t
N
u
m
b
e
r
:
Size:  
Ba  
Date:27-Sep-2001  
Rev:A  
Sheet 1 of  
0
3
M
7
K
D
U
3
0
.
S
C
H
1
MIC  
LEVEL  
PAD  
SENSITIVITY  
PWR  
 

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