LBB1930
LBB1935
VU
LBB1938
VU
100V
70V
F701
F702
en
Connecting loudspeakers
Constant voltage loudspeakers
The booster amplifier can drive 100 V constant voltage loudspeakers at full power (100 V) or half power (70 V).
Connect the loudspeakers in parallel and check the loudspeaker polarity for in-phase connection. The summed
loudspeaker power should not exceed the rated amplifier power.
LBB1938 only:
Ensure that the fuse for loudspeaker voltage selection is properly set (see page 11). The Priority Only and No Priority
outputs are controlled by a priority relay. The Priority Only output only provides priority announcements, while the No
Priority output just provides the program signal and switches OFF at priority calls.
You can also use the Priority Only output for 3-wire remote volume control override. In this case, ensure that the
selected voltage for the Priority Only output is the same as for the direct output used.
Low impedance loudspeakers
Connect low impedance loudspeakers to the 8 Ohm/0 terminals. This output can deliver the rated output power into an
8 Ohm load.
Connect multiple loudspeakers in a series/parallel-arrangement to make the combined impedance 8 Ohm or higher.
Check the loudspeaker polarity for in-phase connection.
100V
70V
8Ohm
0
100V 70V
0
0
100 V
100V
70V
8Ohm
100 V
0
0
Priority Only
Direct Output
No Priority
0
100V
0
70V
0
Priority Controlled Output
Priority Only
100V
0
Priority Only No Priority
24V DC IN
0
8
-
+
8 Ohm
4 Ohm
4 Ohm
8 Ohm
8 Ohm
70 V
8 Ohm
8 Ohm
8 Ohm
8 Ohm
8 Ohm
8 Ohm
70 V
4 Ohm
4 Ohm
8 Ohm
0
8
No Priority
100V
0
23
BOOSTER AMPLIFIER
+
100 V
1
GND
-
2
GND
+
0V
3
1
2
-
3
230 V-
100 V
100 V
70V
240 V-
0
0
24V
DC IN
8
-
+
line out
Lin e
fus e
250 V
T1A
Wa rnin
This
g
App ara
app arat
tus del
us mus
con nec
iver ed
t be
ted for
eart hed
230 V-
8 Ohm
8 Ohm
Wa rnin
g
This
app arat
us mus
t be
ear thed
LBB1930
LBB1935
LBB1938