Owner's Manual

9
Some words about Power and Ground
The second most common cause of under performing amplifiers is insufficient power
current or a poor power connection. The most common cause of under performing
amplifiers is insufficient ground current or a bad ground connection.
12-volt current: Battery power works only if it travels in a complete circuit from the battery
positive terminal to the battery negative terminal. Main power input, of course, is attached
to the battery positive terminal. Ground current is returned to the battery through the
chassis to the point where the battery is grounded.
The current available for your amplifier to use to produce power will be restricted by the
smallest gauge of wire in the circuit and by the weakest physical connection in the circuit.
Wire Size
It's often surprising how many people will obsess about signal wire but routinely provide
the amplifier with only a fraction of the current it needs to do its job. The most common
wire gauge used in car audio is 10-gauge, and the most common location for amplifiers
is in the trunk.
8
Planning your power connections
The power end plates of the Zapco SP amplifiers carry the power connections and the
speaker connections and vary somewhat by the number of channels. For example, the
power end of the Z-150.6 SP below has (of course) speaker connections for six channels.
One model, the Z-150.2 SP has on-board fuses, while all other models will require and
in-line fuse with a rating as in the specifications page at the end of this manual. That
said, the main 12-volt power input, the 12-volt turn-on wire, and the main Ground
connections are common to all models.
• The gold connection at the interior of the end plate is the main power input. This
must be connected the vehicle battery's positive (+) terminal, and a main system
fuse should be placed close to the battery
• The silver connection at the outside of the end plate is the main ground or negative
connection. This must be securely attached to bare metal at the vehicle frame, or
other heavy chassis component with a direct connection to the frame
Note: Seat bolts and seat belt bolts are NOT good ground points
• The small terminal between the main power and ground is the +12 turn-on input
and can be connected to the head unit turn-on output wire. If none is available it
can be connected to an accessory (ACC) terminal. You should avoid using any
ignition-on (IGN) wire, as they can be noisy
Note: The Z-Series SP amplifiers have terminals that do not require connectors. You simply
insert a bare portion of wire and tighten the connection with the supplied Hex tool. As the wire conforms to
the connector the connection can loosen. You should re-tighten the connection after about a week.
Turn-on trigger wire
+12 volt at Battery positive terminal Ground to chassis
Wire Sizing Chart
4 ft 7 ft 10 ft 13 ft 16 ft 19 ft 22 ft 28 ft
0-20 amps 14 12 12 10 10 888
20-35 amps 12 10 886664
35-50 amps 10 8866444
50-60 amps 88644442
65-85 amps 66442220
85 -105amps 66422220
105-125 amps 44422000
125-150 amps 22220000
Let's look at a fairly small system. If you use a 50 watt/ch amp (25 amps) for the highs and
a 100 watt/ch amp (40 amps) for the woofers, you need at least a 4-gauge and maybe a
2-Guage wire to provide 65 amps at the trunk. Use the Wire Sizing Chart. Add up the fuse
values on the amplifier(s) then choose the proper size wire based on the distance from
the car battery to the amplifier location. Always use the same gauge wire for the main
ground as you do for the main power. Always make your ground as short as possible and
secure it to a clean solid surface, preferably the vehicle frame.
Length of Run