Specifications
Page 8
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.
codes.
120 VAC, 60 Hz North American units do not have a
convertible transformer, and cannot be used at other
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.
Fig. 2.3 AC Mains Voltage Conversion
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 prevent
high-frequency oscillations, follow these guidelines:
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 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. The 120 volt models and the European
models have the appropriate plug. The other 200, 220
and 240 volt models have a North American 120 volt
plug. The installer must cut off the plug and supply and
install a plug appropriate for the installation.
Note:
Crown assumes no liability whatsoever for ungrounded
operation, nor for violation of UL or local electrical