Ac Mains Power Requirement; Fuse Selector Nomograph; Ac Mains Voltage Conversion - Crown DC-300A II Reference Manual

Littlefuse 361000 series. If the loudspeaker is only sus-
ceptible to damage caused by prolonged overload
(such as overheating), use a fuse or circuit breaker
having the same slow thermal response as the loud-
speaker itself (such as a slow-blow fuse).
The nomograph in Figure 3.9 shows fuse size versus
loudspeaker peak power rating. It can be used to de-
termine the size of the required fuse.
1.0
1.2
1.4
1.6
2
2.5
3
4
5
6
Example:
Impedance = 8 ohms.
7
Peak Power = 75 W
8
Answer: Fuse = 1.5 A
9
10
12
14
16
20
25
30
40
Fig. 3.9 Fuse Selector Nomograph

3.3.5 AC Mains Power Requirement

All units have a standard three wire, grounded AC cord
and plug as specified by UL requirements for North
American 120 VAC, 60 Hz units. Note: Crown assumes
no liability whatsoever for ungrounded operation, nor
for violation of UL or local electrical codes.
Five standard line voltages are supported, including
100, 120, 200, 220 and 240 VAC. The unit may be op-
erated at AC mains frequencies from 50 to 400 Hz. The
model-voltage sticker on the back panel indicates the
unit's factory configuration.
WARNING: Risk of electric shock! Only a qualified
technician should attempt to alter your amplifier's
AC mains voltage configuration.
To operate your amplifier at a different line voltage, you
will need a phillips screwdriver. Then follow these steps:
Page 14
20
3000
15
2000
10
1500
8
1000
800
6
600
5
4 400
300
3
200
150
2
100
80
1.5
60
1
40
.8
30
.6
20
.5
15
.4
10
8
.3
6
4
.2
3
.15
2
1.5
.1
1
.08
1. Turn the amplifier off and disconnect it from the
AC mains.
2. Remove the perforated top cover by removing
the 12 phillips screws that hold it in place.
3. Find the power transformer. The terminal strip
with six connector tabs is wired to the trans-
former.
4. Change the appropriate jumpers for the desired
operating voltage (see Figure 3.10).
5. Make sure the proper fuse is installed. Use only
a 5 amp, 250 volt, type MTH fuse for AC mains
of 200 volts or more; use only a 10 amp, 250
volt, type AB fuse for AC mains below 200 volts.
6. Carefully check all connections.
7. Repeat steps 1 and 2 in reverse order to reas-
semble the unit.
IMPORTANT: Use only a 5 amp, 250 volt, type MTH
fuse for 200, 220 or 240 VAC operation; use only a
10 amp, 250 volt, type AB fuse for 100 or 120 VAC
operation.
100 V
A B
120 V
A B
200 V
A B
220 V
A B
240 V
A B
Fig. 3.10 AC Mains Voltage Conversion
DC-300A II Power Amplifier
C D E F
C D E F
C D E F
C D E F
C D E F