Blaupunkt Velocity V250 Owner's Manual page 16

"CLEAN" POWER AND GROUND
Unfortunately, the number of electronic devices in the car has grown such that care must be taken
to properly install the power and ground connections of the amplifier in order to prevent
overloading the charging system of the vehicle or interjecting noise. Currents are high enough that
a dedicated power line should be run directly to the battery of the car, but not to the vehicle's
alternator output. This line should not be run to a fuse on the factory fuse panel of the car but
directly to the battery with its own fuse immediately at the battery.
amplifier should be terminated at the other end to a clean metal on the chassis of the car.
Noise can enter over the battery power line, power ground, or most commonly over the RCA signal
input lines. The amplifier has very high rejection to noise coming in over the heavy power line so
most noise intrusion is via the ground connections and/or RCA input leads. Although this amplifier
has Differential Inputs at the RCA leads, noise can still enter the shields of the RCA cables if these
are run near noise producing objects such as engine or braking system computers. More common
is alternator whine generated from ground point voltage differences due to component connections
throughout the vehicle (voltage ground loops). The best installation design to prevent this
condition is done using a "star" grounding scheme (shown below) to ensure a common ground
point for all stereo components.
Radio
PROPER FUSING
This unit will operate over a range of lo-18 volts DC. A high current fuse should be installed in-
line with the amplifier(s) immediately at the battery to prevent vehicle damage should the battery
line be inadvertently shorted to the vehicle chassis. The chart below shows recommended master
fuse sizes for an average audio system with the noted audio power levels.
F U S I N G C H A R T *
FUSE SIZE
(in Amperes)
Standard fuse sizes commonly used in the automotive world today. Fuse size should exceed the maximum current
draw expected to accommodate music transients. (Current draw above reflects a minimum system voltage of 12.6
dc at the amplifier with current values for maximum current draw with music signals.)
16
Equalizer (Optional)
"Star" Ground
.
FUSE SIZE FOR TOTAL SYSTEM AUDIO POWER (max output level)
50 w 100 w
(4 A rms) (8 A rms)
15 2 0
The ground terminal of the
200 w 500 w
(40 A rms)
(16 A rms)
3 0 5 0
1000 w
(80 A rms)
100