Crown Audio DC-300AII - Manual (Page 14)

DC-300A II Power Amplifier
Page 14
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.
Fig. 3.10 AC Mains Voltage Conversion
A C B D F E
A C B D F E
A C B D F E
A C B D F E
GRN
–WHT
YEL
–RED
BLK
–GRN
BLU
–YEL
BLK
WHT
100 V
WHT
120 V
200 V
220 V
240 V
ORN
A C B D F E
1.0
1.2
1.4
1.6
2.5
3
4
5
6
7
8
9
10
12
14
16
20
25
30
20
15
10
8
6
5
4
3
2
1.5
1
.8
.6
.5
.4
.3
.2
.15
.1
.08
3000
2000
1500
1000
800
600
400
300
200
150
100
80
60
40
30
20
15
10
8
6
4
3
2
1.5
1
LOUDSPEAKER IMPEDANCE
(ohms) FUSE (amps)
LOUDSPEAKER RATING
PEAK MUSIC POWER
(watts)
(Typically 4 times the continuous average power)
Answer: Fuse = 1.5 A
2
40
Example:
Impedance = 8 ohms.
Peak Power = 75 W
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:
Fig. 3.9 Fuse Selector Nomograph
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.