PERTRONIC INDUSTRIES LTD
50W AMPLIFIER PREAMP
INSTALLATION NOTE ISSUE 3.1
Pertronic Industries Ltd
1 of 2 0323 50W Amplifier Preamp Iss 3.1 20160927
Overview:
The 50W Amplifier Preamp is a piggyback board designed to enable the connection of a
public address or fire microphone to the Pertronic Industries 50W Amplifier.
The 50W Amplifier Preamp is easily connected to the 50W Amplifier by simply plugging it into
two provided connectors. No separate supply or connection is needed.
The microphone input is balanced for maximum noise immunity, and is designed specifically
for moving coil microphones. A switch input is available for monitoring a ‘Push to talk’ switch.
A 100 mVrms line input is provided for when a pre-amplified signal is used, as in a noisy
environment or for a remote microphone.
Jumpers are available on the board for selecting which mode the amplifier is to operate in.
Operation of the 50W Amplifier Preamp is country specific. Please see table 1 for details.
Table1. Operation
New Zealand
Australia
Link Selected
Normal
Alarm
Normal
Alarm
PA
Operational
Disabled
Operational
Disabled
FIRE
Disabled
Operational
Operational
Installation:
50W Amplifier Preamp Connection:
The Preamp is connected to the 50W Amplifier by piggybacking it onto connectors provided
on the 50W Amplifier PCB.
First remove the link labelled MJ6 from the 50W Amplifier. Insure that a 10 way IDC box
header is installed just a
bove the ‘100’s’ BCD switch. If the IDC box header is not installed,
then the 50W Amplifier is not compatible with the Preamp.
Position the 50W Amplifier Preamp so that the microphone connector is aligned to the same
side as the 50W Amplifier’s RS485 connector. Line up the Amplifier Preamp’s 10-way and 3-
way plugs with the appropriate connectors provided on the 50W Amplifier and gently insert.
Use the provided standoff to securely mount the 50W Amplifier Preamp to the Amplifier. If the
50W Amplifier Preamp is installed correctly, the 50W Amplifier when active will operate
normally even when no microphone is connected. Note: Monitoring of the 100V line ceases
whenever an announcement is made. This is to make allowance for the monitoring circuit
confusing a long pause in an announcement as a short circuit.
Fig1. Location of 50W Amplifier Preamp
