4
SUPPLYING POWER TO THE GTI AMPLIFIER
POWER IN IS
POWER OUT
In order to get full power out of your
amplifier, you must provide full power to
your amplifier. That’s a basic rule
of physics. The A6000GTi amplifier
can draw nearly 800 amperes when
reproducing sine waves at full output.
Both JBL A6000GTi and A3000GTi ampli-
fiers can quickly exhaust the
factory-installed charging system of
any vehicle on the road today. With this
much available amplifier power, you will
need to beef up your vehicle’s
electrical system to satisfy the
amplifier’s current demands. We
recommend adding at least two
12-volt batteries, connected in
parallel with cold-cranking capacities
of at least 600 amperes each, to the
factory-installed charging system.
HOW YOUR CHARGING
SYSTEM WORKS
The battery’s job is to start your
vehicle. Running the electrical
accessories is the alternator’s job.
The battery isn’t designed to be a
continuous source of power. It is a
renewable source and is charged by
the alternator when the engine runs.
Battery charging can only occur when
the current demand from the electrical
accessories is less than the total cur-
rent output capacity of the alternator.
PROGRAM MATERIAL
AND CURRENT DEMAND
Music is a combination of loud and
soft sounds, with varying durations
and rhythms that present unique
current demands during amplification.
For example, it may take full power
to reproduce the sound of a kick
drum. The peak power demand doesn’t
last very long, but it is repeated over
and over.
If your charging system can’t provide all
the power your amplifier needs on
a continuous basis, it still may be
adequate. During the sound of the
kick drum, the battery can provide
the extra current that’s necessary,
and between kick drum beats, the alter-
nator will put some of the energy back
into the battery.
However, depending on the current rat-
ing of the alternator, the amplifier’s
maximum output power, the music
content, and the charging system’s
capability, the alternator may not be
able to keep up over time. In that case,
you’ll need to install a somewhat larger
alternator for more current, or adjust
your driving and listening habits, to give
the alternator time to catch up with the
amplifier’s current demand.
Few stock batteries can provide the
current required to reproduce even
short-duration musical peaks. Adding
a pair of batteries with cold-cranking
capacities of 600 amperes will provide
extra current for short music bursts, but
reserve power may still be
depleted over longer music intervals.
Adding more batteries will provide more
reserve power and current, but no mat-
ter how many are installed, the alterna-
tor will still have to recharge them all.
If you plan to use the A6000GTi or
A3000GTi in SPL competition, the charg-
ing system requirements will be much
greater than those for normal music lis-
tening. Be prepared to add additional
batteries
and
alternators to provide
continuous current required for contin-
uous duty.
See your authorized JBL car audio
dealer for help in designing and
installing an upgraded charging
system to support your GTi amplifier.
