Rockford Fosgate 1000 Installation And Operation Manual page 35

Symptom
Engine Noise
Engine Noise when
using high level
inputs
• If noise persists, see your Authorized Rockford Fosgate Dealer.
Diagnosis
Noise is radiating into RCA
signal cable.
Bad component in the sig-
nal chain.
Noise is radiating into
speaker cables.
Multiple grounds in the
audio system.
Ground loop between source
unit and antenna.
TOPAZ input circuitry (in
Rockford amps) or floating
input circuitry (in non-Rock-
ford amps) does not have
reference to "chassis
ground." This noise, if any,
occurs at the auxiliary am-
plifier whose inputs are fed
from the pass-thru output of
the first amp.
– 30 –
Remedy
Check connections, run the
RCA cables on a different route
away from sources of high
current.
Check connections, bypass
additional components (cross-
overs and equalizers) between
the source unit and the ampli-
fier. Connect one component
at a time to determine the
culprit. Repair or replace com-
ponents as necessary.
Disconnect existing speakers
and connect a test speaker to
the output terminals of the
amplifier. If noise is gone, re-
route the speaker cables away
from sources of high voltage.
Check ground connections and
connect amplifiers, signal pro-
cessors, and other components
to a central location or try a
different grounding point on
the chassis.
Check connections, disconnect
antenna from source unit. If
noise is gone, install an an-
tenna ground loop isolator.
Supply reference ground to the
TOPAZ input circuit (or float-
ing input circuit in non-Rock-
ford amps). Connect shield of
RCA input from auxiliary amp
to chassis ground of radio. An
alternative method is to con-
nect the RCA shield to the
amplifier's power ground ter-
minal.
TROUBLE-S
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