NOISE PROBLEMS
WHINING NOISE VARYING WITH ENGINE
REVOLUTIONS:
Do this:
1.
Rewire the power supply (12 V) to source
unit direct from battery.
2.
Rewire ground wire from source unit to
clean position on chassis.
3.
Check all power connections to ensure that
they are clean and tight.
4.
Check quality of system ground connection.
5.
Install a Power Cap capacitor. This can be
helpful against most noise problems.
CONSTANT WHINING NOISE:
Do this:
1.
Ensure that all equipment has a common
ground point.
2.
Check quality of earth strap connection from
battery negative terminal to chassis.
3.
Disconnect signal cables from amplifier to
see if noise disappears. If so the leads are
picking up noise. Test this by laying a new
cable over the seats and reconnecting to the
amplifier. If the noise does not return, re-
route original cable away from source of
interference.
If noise remains regardless of cable position,
try to use so called Quasi-balanced signal
cables. DLS PRO-cables are
Quasibalanced.
SPEAKER POLARITY CHECK.
All speakers in a car audio system should be
connected in phase (the same polarity). All spea-
ker cones must move in the same direction. Out of
phase speakers will cause a lack of bass, and a
poor stereo soundstage.
Checking polarity:
Hold the - connection of the speaker wire to the -
terminal of a 1,5 Volt flashlight battery. Tap the +
wire on to the + terminal of the battery, and observe
the movement of the cone. The cone should move
outwards when the wire touches the battery, and
inwards when the battery is removed. If it is the
other way around, the speaker has been connected
backwards and it must be removed and connected
correctly.
If your system also has a subwoofer connected
through a passive 6 or 12 dB crossover, try to
connect this with various polarity and judge what
sounds best. The phase shift in passive crossovers
sometimes makes it necessary to change polarity.
+
-
+
-
Battery
1,5 Volt
NOTE!
Tweeters can not be tested this way,
double check the connections instead.
Professional Tip:
Professional Tip:
Professional Tip:
Professional Tip:
Installing in trunk
When installing the amplifier in the trunk, run the
power wires along the same path as the other
vehicle wiring. Many cars have insulated channels
for wiring. you will have to remove the door sill trim
and the carpet.
Securing wires
Use wire ties to bundle together when possible.
(But never bundle speaker wires or signal cables
together with power wires.
Professional Tip:
Professional Tip:
Speaker and power wires
Do not run speaker and power wires next to each
other. Power wires can generate a ”siren” sound in
the speakers. Runs speaker and power wires on
opposite sides of the car.
Crimp connections
Purchase crimp connectors and crimping tool.
Connectors are color coded.
1. Strip 1/4 inch (6 mm) of insulation from the wire.
2. Insert into connector
3. Crimp tightly
13
CA20, 21 & 40
Summary of Contents for CA20
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