2
SIMPLIFIED EQUIVALENT CIRCUIT (ONE CHANNEL)
FIGURE 1
POWER CONNECTIONS
Connect the AC power plug to
a grounded 90 to 132 Vac, 50/60 Hz
power source. Turn the Power switch to ON. The LED lamp above
the power switch will light when power is applied. If the PS1A is to
be operated from a 180 to 264 VAC, 50/60 Hz power source, the
modification described in the next section must be performed.
OPERATION
Installation
The PS1A can be installed anywhere along the microphone line
between the microphone and the mixer, audio console, amplifier or
tape recorder, and convenient to an AC power
source.
Connect one or two SM81, SM82, SM85 or other Shure condenser
microphones to the PS1A Microphone Connectors.
When using other manufacturer's condenser microphones with the
PS1A, verify that the voltage and resistance requirements are
compatible.
Connect a second cable from each PS1A Output Connector to a mixer
input connector.
The design of the PS1A permits the simultaneous operation of both a
microphone-level and a line-level condenser microphone.
The PS1A phantom powering system uses the balanced audio cable
pair to carry the supply current to the microphone. The cable shield
is used as a ground return.
Use only high-quality microphone cables, as intermittent shorts
between broken shield wires and the balanced conductors will
interrupt the current, causing large noise transients
in the system.
Avoid ground loops that may occur due to connector shells or the
microphone case touching other metal objects.
Incorporate generally accepted audio grounding practices.
Note that a PS1A can be used with either balanced or unbalanced
low-impedance microphone inputs.
SERVICE
240V Operation
The PS1A is designed for operation from either a 90 to
132 VAC, 50/60 Hz
or a 180 to 264 VAC, 50/60 Hz ac power source. The operating voltage is
selected by an internal switch, and the unit is supplied with the switch
set for 90 to 132 VAC operation.
For operation from a 180 to 264 VAC, 50/60 Hz power source, follow
these steps:
1. Unplug the AC line cord and remove the two self-tapping
screws securing the top cover.
2. Remove the top cover.
3. Locate the voltage selector switch and move it to the 240V
position.
4. Replace the line cord (if necessary) with one designed for the new
AC source. If the PS1A is to be used outside the U.S. and Canada,
local regulations may require replacing the line cord with one having
wire insulation colors as follows:
5. Replace the top cover and mark the rear panel to reflect the
new operating voltage.
WARNING
TO REDUCE THE RISK OF FIRE OF ELECTRIC SHOCK, DO NOT
EXPOSE THIS APPLICANCE TO RAIN OR EXTREME MOISTURE.
WARNING
Voltages in this equipment are hazardous to life.
Refer servicing to qualified service personnel.
“Live” or
“Hot”
Neutral
“Earth” or
“Ground”
U.S., Canada
Black
White
Green
Europe
Brown
Blue
Green/Yellow
