LA Audio PC90 User manual

User Manual

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Contents.
Copyright Information. 4
Thank You. 5
Important Safety Information. 6
Introduction. 7
Getting Started. 8
Operating Instructions. 9
Application Notes. 10
Cable Testing. 1
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Specifications. 12
Warranty. 13

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Copyright Information.
© LA Audio, 2005. All rights reserved.
The information in this document is subject to change without notice.
LA Audio makes no warranty of any kind with respect to the material in this
document and shall not be liable for errors contained herein or for incidental
or consequential damages related to the use of the material.
No part of this document may be reproduced without the prior written
consent of LA Audio.
Thank You.
By buying PC90, you have joined the ranks of the thousands of professional
engineers, installers and musicians who choose LA Audio. We hope your PC90
brings you many years of enjoyable polarity checking!
This manual should get you up to speed with the PC90’s capabilities, controls
and specifications. It also details safety precautions that must be taken for
the safe use of this equipment. Please take the time to read this information
carefully and store this manual for future reference.

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Important Safety Information.
COVERS
DO NOT remove the covers. Refer servicing to qualified personnel only.
MOISTURE
DO NOT expose the unit to rain or moisture. If your PC90 should become
so exposed, remove the unit from the source of moisture and allow to dry
thoroughly before attempting use again.
HEAT
ALWAYS site your PC90 away from sources of heat including direct sunlight
and ensure adequate ventilation around the unit.
REGULATORY COMPLIANCE
This product complies with both the EMC Directive (89/336/EEC) and the Low
Voltage Directive (73/23/EEC) as issued by the Commission of the European
Community. Compliance with these directives imply conformity with the
following European standards:
 EN60065 Product safety
 EN55103-1 Electromagnetic Interference (Emission)
 EN55103-2 Electromagnetic Susceptibility (Immunity)
Introduction.
The PC90 is an advanced measuring system which allows you to check the
polarity of any electronic audio signal path. It’s an ideal tool for numerous
applications and should take pride of place in your toolbox.
For a system to perform correctly, the polarity of the signals must be
maintained from input to output. Unintentional polarity reversal needs to be
avoided, and this is what the PC90 checks for.
The system is in two parts, an emitter and receiver, which can be placed at any
point in an audio system. The emitter produces a 1Hz pulse, which can be sent
acoustically or electronically to the receiver, which determines polarity.
This manual is your guide to exactly how the PC90 functions, and how you
should look after it to ensure its continued faithful service. Please have a good
read before use.

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Getting Started.
INSPECTION & UNPACKING
The PC90 is carefully packed at the factory in a carton designed to withstand
transit handling, however, if transit damage is evident, DO NOT discard any of
the packaging and notify the carrier immediately, it is they who are responsible
for any claims.
OPERATING ENVIRONMENT
The units are designed to operate between 0 and 50 deg C (32-122 F) and in an
atmosphere of relative humidity up to 80%.
POWER REQUIREMENTS
Each unit is powered by a 9V PP3 battery, which is fitted by removing the
battery cover and attaching the battery to the connector provided.
Operating Instructions.
During operation, the emitter produces a series of special pulses which are fed
into the system by using either the built-in speaker or by connecting the XLR
output to a line or microphone input. The line output level can be adjusted
using the front panel control knob, however the speaker level is fixed.
Once the emitter’s signal has been fed through the system, the receiver will tell
you whether it has arrived in or out of phase by its green and red LEDs. Like
the emitter, the receiver can accept audio signals in one of three ways:
• Selecting INT uses the internal microphone.
• Selecting EXT allows an external microphone to be used. Remember,
though, that the unit cannot provide phantom power for connected mics.
• Selecting LINE allows a line level signal to be used.
When using XLR connections, a selector switch on both the emitter and
receiver allows the system to adapt for different wiring conventions – either
pin 2 hot or pin 3 hot. Make sure that both of these are set to the same state,
and that this matches the cables in use.

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Cable Testing.
The PC90 is designed to be a
polarity tester for electronic
audio systems, not specifically
a cable tester.
If a false reading is found in
a system and a cable fault is suspected then ideally a dedicated cable tester
should be used to trace the fault. However, if you want to check an individual
XLR cable and the PC90 is what you have at hand:
• Set the 'Hot Pin' switch on both units to Pin 2 and select 'LINE' as the input
on the Receiver.
then,
• Set the 'Hot Pin' switch on both units to Pin 3.
If the cable is correct the green ‘IN’ LED will flash in both cases, if the cable is
reversed it will show nothing, thus indicating a fault condition.
Note: The Emitter’s level control should be set to about 3 o'clock for this test.
Application Notes.
There are various applications for the PC90. Below are a few suggestions about
how to get the best from your PC90.
• Feed the signal from the emitter into a PA system and place the receiver in
front of each loudspeaker in turn to ensure that the system is in-phase.
• For a multi-mic application, connect the receiver to a mixing console
output and feed each microphone with the generated pulse. The receiver
may then be used to check that all the mics are in phase, (if out of phase,
cancellation effects may occur where mics are close together).
• The system may be used for checking phase transmission on tape
recorders, (be prepared for some surprises!). This test can be made by
recording the generated signal onto tape and connecting the receiver to
the machine's output. This is really useful in the recording studio, when
using effects off tape which are combined and for checking tape machine
wiring.
• The system may also be used to check telephone lines, satellite links etc.
Keep in mind that some crossover networks and speaker systems
deliberately place certain speakers out of phase for correct operation.
Check the technical specifications of the system before making any polarity
adjustments.

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Specifications.
GENERATOR
Pulse rate 1Hz
Frequency spectrum, electrical 1Hz to 20KHz
Frequency spectrum, acoustic 200Hz to 5KHz
Output level, electrical 0 to 1V (Acoustic level is fixed)
Output load impedance >1KΩ
Output source impedance 1KΩ
Power 9V PP3 battery (= approx 50 hours)
Power drain 10mA
RECEIVER
Frequency spectrum, electrical 1Hz to 20KHz
Frequency spectrum, acoustic 10Hz to 1KHz
Input impedance (Mic) 1KΩ
Input impedance (Line) 10KΩ
Input level (Mic) 10mV - 1V
Input level (Line) 0.5V to 50V
Output level 0V to 1V
Power 9V PP3 battery (= approx 50 hours)
Power drain 10mA
PHYSICAL CHARACTERISTICS (each box)
Dimensions 140mm W x 80mm D x 50mm H
Weight 0.25 Kg
Shipping weight 0.65 Kg
Operating temperature 0 - 50 deg C
Storage temperature -30 - +75 deg C
Warranty.
Your LA Audio PC90 has been manufactured to a high standard using quality
components. If correctly installed and operated the unit should give years of
problem free operation.
However in the event of a defect in material or workmanship causing failure of
the unit within 1 year of the date of original purchase we will agree to repair, or
at our discretion replace, any defective item without charge for labour or parts.
To receive service under this warranty it is necessary to return the unit to an
LA Audio authorised service centre or to the factory with a dated receipt as
proof of purchase. After repair the unit will be returned to you free of charge.
Limitations:
This warranty does not cover damage resulting from accident or misuse.
The warranty is void unless repairs are carried out by an authorised service
centre. The warranty is void if the unit has been modified other than at the
manufacturers instruction. The warranty does not cover components which
have a limited life, and which are expected to be periodically replaced for
optimal performance. We do not warrant that the unit shall operate in any way
other than as described in this manual.

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