Orion 220gx Installation Manual page 28

The ground lead is every bit as important as the
power lead. Many audio systems troubles are the re¬
sult of improper ground connections.
Ground is a term generally used to describe the com¬
mon connection in an electrical or electronic circuit.
The common connection is usually the same potential
for all circuits in the system. It is the source of electron
flow. Remember that the basic princple is that electrons
flow from negative to positive.
In cars, the ground is almost always the metal chassis
or body and originates at the negative (-) terminal of
the battery.
A ground connection should have the least possible re¬
sistance which is why we emphasize that the ground
wire for an amplifier should be as short as possible
(18-inches long maximum). Longer wires add resistance
and make the circuit susceptible to ground loops which
can result in hum pickup and other electromagnetic
interference.
Electromagnetic interference is a combination of elec¬
tric and magnetic fields caused by alternating current
(or frequencies) radiating from the wires and being
picked up on the signal leads to and from your ampli¬
fier. This type interference may show up as popping,
bursts of static, or random noise.
Floating Ground
Floating ground means that the ground is not connected
to the car chassis or body, but uses only the internal
power supply ground. Some radios and cassette decks
use a floating ground for the output signals. This is a
dedicated ground connection that remains isolated
from the common circuit ground (car chassis or body).
All ORION amplifiers contain a small diameter black
lead in addition to the larger common ground wire.
This lead is for connections to the floating ground for
those decks that use a floating ground.
To determine if the floating ground connection should
be made, first connect the system WITHOUT connect¬
ing the floating ground. Start the car and turn on the
audio system. Temporarily connect the floating ground.
If the floating ground adds noise, do NOT connect. If
the floating ground takes away noise, connect the
floating ground permanently.
If the deck utilizes a floating ground and the small
black wire is not connected to the deck floating ground
point, any of the following conditions may result:
Clipped output
Blown fuses
Weak output from the amplifier
Amplifier will run hot
Squealing
Phantom Power
Phantom Power (+15V and -15V) is present at all
DIN connectors at the INPUT to all ORION amplifiers.
This voltage is for use in providing operating power to
any ORION accessory that contains active electronic
circuits. This includes all crossover modules, bridging
modules, equalizers, and low pass and high pass filters.
NOTE:
Active electronic circuits require a source of
dc power for operation, offer no resistance to the sig¬
nals, and often add gain. Passive electronic circuits,
such as used for speaker crossovers, do not require dc
power and add resistance to signals.
The ORION accessories use insignificant amounts of
power and need not be figured into the overall power
requirements for you audio system.
RCA INPUT CONNECTORS
(CONNECTED IN PARALLEL
WITH DIN CONNECTOR
SIGNAL CONNECTIONS)
POWER ON
INDICATOR
RIGHT
INPUT
SIGNAL
-15V
PHANTOM
POWER
AUDIO
GROUND
\Jl.X
LEFT \
INPUT \
SIGNAL >
—H5V
PHANTOM
POWER
INPUT DIN CONNECTOR