Page 11
CP660
Six Channel Amplifier
Reference Manual
3.3.3 Output Connection
Consider the power-handling capacity of your load be-
fore connecting it to the amplifier. Crown is not liable for
damage incurred at any time due to overpowering. Fus-
ing loudspeaker lines is highly recommended (see Sec-
tion 3.3.4). Also, please pay close attention to Section
4.1,
Precautions.
You should always install loudspeaker cables of suffi-
cient gauge (wire thickness) for the length used. The
resistance introduced by inadequate output cables will
reduce the amplifier’s power to, and motion control of,
the loudspeakers. The latter problem occurs because
the damping factor decreases as the cable resistance
increases.
Use the nomograph in Fig. 3.4 and the following proce-
dure to find the recommended wire gauge (AWG or
American Wire Gauge) for your system.
1.
Note the load resistance of the loudspeakers con-
nected to each channel of the amplifier. Mark this
value on the
Load Resistance
line of the nomo-
graph.
2.
Select an acceptable damping factor and mark it on
the
Damping Factor
line. Higher damping factors
yield lower distortion and greater motion control over
the loudspeakers. A common damping factor for
commercial applications is between 50 and 100.
Higher damping factors may be desirable for live
sound, but long cable lengths often limit the highest
Fig. 3.2 Balanced Input Wiring
Fig. 3.3 Unbalanced Input Wiring
3. Draw a line through the two points with a pencil, and
continue until it intersects the
Source Resistance
line.
4. On the
2-Cond. Cable
line, mark the length of the
cable run.
5. Draw a pencil line from the mark on the
Source Resis-
tance
line through the mark on the
2-Cond. Cable
line,
and on to intersect the
Annealed Copper Wire
line.
6. The required wire gauge for the selected wire length
and damping factor is the value on the
Annealed Cop-
per Wire
line.
Note: Wire size increases as the AWG
gets smaller.
damping factor that can be achieved practically. In
recording studios and home hi-fi, a damping factor of
500 or more is desirable.