Advantages Of Direct Constant-Voltage Operation In Crown Power
Amps Electric-power companies have a good idea which has been
applied to audio engineering. When they run power through miles
of cable, they minimize resistive power loss by running the
power as high voltage and low current. To do this, they use a
step-up transformer at the power station and a step-down
transformer at each customer's location. This reduces power loss
due to the I2R heating of the power cables. The same solution
can be applied to audio communications in the form of a
constant-voltage system (typically 70 volts). Such a system is
often used when a single power amplifier drives many
loudspeakers through long cable runs (over 50 feet). Some
examples of this condition are distributed speaker systems for
P.A., paging, or low-SPL background music. What is constant
voltage? The label "constant voltage" has been confusing because
the voltage is really not constant in an audio program. A better
term might be "high voltage." Figure 1 shows a