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D-45 / D-75A Power Amplifiers
2.3.3 Output Connection
There are many methods that can be used to prevent
potential output problems, but the most important pre-
ventative measure is to use good common sense.
voltages and frequencies. International units can be
operated with an AC mains frequency of 50 to 400 Hz,
and can be configured for five different line voltages:
100, 120, 200, 220 and 240 VAC. The back panel
sticker indicates the unit’s factory configuration.
WARNING: Risk of electric shock! Only a compe-
tent technician should attempt to alter your
amplifier’s AC mains voltage configuration.
To operate an international unit at a different line volt-
age, you will need a phillips screwdriver and a solder-
ing iron. Then follow these steps:
1. Turn off the amplifier and disconnect it from the AC
mains.
2. Remove the top cover by removing the six screws
that hold it in place.
3. With the unit’s top side up and the front panel to-
ward you, locate the terminal strip toward the front
of the amplifier on your right.
Fig. 2.3 AC Mains Voltage Conversion
A
C
B
D
F
RED–BLK
BLU
BLK–WHT
BLU–WHT
WHT
WHT
100 V
E
BLK
A
C
B
D
F
120 V
E
A
C
B
D
F
200 V
E
A
C
B
D
F
220 V
E
A
C
B
D
F
240 V
E
ORN
Use Good Connectors
1. To prevent possible short circuits, do not ex-
pose the loudspeaker cable connectors.
2. Do not use connectors that might acciden-
tally tie conductors together when making or
breaking connections (for example, a stan-
dard three-wire stereo phone plug).
3. Never use connectors that can be plugged
into an AC power receptacle.
4. Avoid connectors with low current-carrying
capacity.
5. Do not use connectors with any tendency to
short.
High-frequency oscillations can cause your amplifier
to prematurely activate its protection circuitry. To pre-
vent high-frequency oscillations, follow these guide-
lines:
1. If you have long cable runs or different amplifiers
sharing a common tray or jacket, use tie-wraps to
bundle together loose pairs of loudspeaker con-
ductors. (Do not bundle wires from different
amplifiers.) This reduces the chance of conductors
acting like an antennas to transmit or receive the
high frequencies that can cause oscillation.
2. Avoid using shielded loudspeaker cable.
3. Never tie together input and output grounds.
4. Never tie together the output of different amplifiers.
5. Keep output cables separated from input cables.
6. Install a low-pass filter in series with each input.
7. Install the input wiring according to the instructions
in Section 2.3.2.
2.3.4 AC Mains Voltage Configuration
North American 120 VAC, 60 Hz units have a standard
three wire, grounded AC plug as specified by UL re-
quirements. Other units are shipped with an appropri-
ate line cord and plug.
Note: Crown assumes no liability
whatsoever for ungrounded operation, nor for violation
of UL or local electrical codes.
120 VAC, 60 Hz North American units do not have a
convertible transformer, and cannot be used at other
