zapco PX Owner's Manual

Model PX

Paragraphic Equalizer With

Electronic Crossover

Owner’s Manual

A.R.P.A. OF AMERICA CORP.
MADE IN MODESTO, CA U.S.A.

Contents

Introduction 2
Installation Instructions 3
PX Equalization Modules 5
Input Gain Adjustment 6
Technical Assistance 7
Manufacturing 8

1

Introduction

The ZAPCO model PX is a programmable four-band equalizer and
12dB per octave electronic crossover housed in an attractive
anodized aluminum chassis designed to be mounted either in­dash or under-dash. The PX is comprised of two pieces: the PX
Main containing all of the audio circuitry and PSi, an isolated
power supply that provides the audio circuitry with + or - 15V
supply rails.

A master volume control and four filter control knobs are readily
accessible on the PX front panel. The filter controls have a
maximum boost or cut of 18dB at either extreme of rotation.
Independent left and right channel INPUT GAIN adjustments are
made via access holes in the lower left hand corner of the front
panel. A main power ON indicator and three OVERLOAD
indicators are provided to aid in system troubleshooting and
calibration.

Signal inputs and outputs are made to the rear of the unit by way
of gold plated RCA connectors. The back panel also contains the
controls for the electronic crossover. The crossover frequency is
continuously variable in a range of 70Hz to 1.6 kHz by using the
CROSSOVER FREQUENCY control pot. Separate LOW / HIGH
PASS OUTPUT LEVEL controls are provided for system
balancing. An auxiliary FULL RANGE output is provided for
possible use with full range satellites or 600 ohm earphone. The
modular “phone” DC POWER INPUT connector at the upper right
hand corner of the back plate is used to connect the PX Main to
the external power supply, the PSi.

The power supply, model PSi, is a highly efficient and compact
switching power supply that provides the PX Main with all
necessary operating voltages. An extra modular output connector
is provided for use with an additional PX. A fifteen foot
interconnecting cable is supplied to allow for remote mounting of
the supply. The PSi is used to trigger on/off operation of the PX
Main. A plug-in barrier strip is used to terminate the necessary
+12V, GND and TURN ON connections to the unit.

2