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4

1. Connect the speakers, observing

proper polarity, to the speaker output
barrier strip on the amplifier using at
least 16G high-quality speaker wire.
(Note: The total impedance of the
speakers connected to the outputs
when the amp is driven in stereo must
be at least 2 ohms.) 

2. If you are bridging the amplifier, con-

nect the speaker wires to the terminals
marked “bridge”, observing proper
polarity. (Note: The total impedance of
the speaker system to be connected to
the amplifier must be at least 4 ohms
in bridge mode.)

3. If you are running the amp in Tri-Mode

(stereo and mono simultaneously to
one or two pairs of satellite speakers
and a subwoofer), refer to the chart
below to determine the capacitor and
inductor values you’ll need to route
bass signals to the woofer, and
midrange and high frequencies to the
satellite speakers. These passive
crossover components will also ensure
that the impedance of the speaker
system doesn’t drop below 2 ohms.

1. If you are using conventional RCA

input connections and a source unit
with output voltage less than 4V, sim-
ply plug the RCA plugs into the RCA
jacks on the amplifier.

2. If you are connecting the amplifier to a

factory-installed source unit, or to a
source unit that only has speaker-level
outputs, connect the speaker outputs of
the source to the speaker input plug on
the amp using the connector provided.

The JBL Decade Series amplifiers can be
mounted in virtually any location inside
the vehicle. However, make sure to keep
the amplifier away from heater vents or
ducts.
1. At the chosen site, use the amplifier

as a mounting template and mark the 
locations of the four mounting holes.

2. Drill a small pilot hole at each marked

location.

3. Mount the amplifier and securely

tighten the mounting screws.

Refer to diagrams on page 3 for connec-
tor locations. 
1. For power, remote and speaker wires,

strip 1⁄4" off one end of each jacket to
reveal bare wire for insertion into the
barrier strip connectors.

2. Locate the 3-connection barrier strip

labeled +Batt, Rem and Gnd. Connect a
black wire (at least 12G for DA4002,
10G for DA6502, DA1002 and DA3504)
to the Gnd terminal and connect the
other end to the nearest bare-metal
chassis component. Then, connect a
red wire (at least 12G for DA4002, 10G
for DA6502, DA1002 and DA3504) from
the vehicle’s +12-volt battery terminal
to the +Batt terminal on the barrier
strip. Finally connect a blue wire (16G)
to the Rem terminal on the barrier strip
and connect the other end to the Rem
output of the source unit. 

FREQUENCY

INDUCTOR

CAPACITOR

Crossover 

6dB/oct. LP

6dB/oct. HP

(4 ohm)

(4 ohm)

75Hz

8.0mH

530µF

100Hz

6.4mH

400µF

125Hz

5.0mH

318µF

150Hz

4.2mH

265µF

175Hz

3.6mH

227µF

200Hz

3.2mH

198µF

DA OM  7/14/98 11:38 AM  Page 4

5

Observe the following color-codes: 
Left+: White
Left–: White with black stripe
Right+: Gray
Right–: Gray with black stripe

4. If you are connecting your Decade

Series amplifier to a source unit with
output voltage higher than 4V, connect
the output signal wires of the source
unit to the floating ground factory head
unit inputs. Because the inputs have an
impedance of 100K ohms, this connec-
tion will provide the best noise-free
performance possible.

Electronic Crossover
The electronic crossover(s) in your
Decade Series amplifier can be selected
as a 12dB/oct. high-pass filter at 120Hz
(HPF), a 12dB/oct. low-pass filter at 80Hz
(LPF) or it can be defeated (FLAT).

Setting Input Sensitivity
Proper input sensitivity control settings
on Decade Series power amplifiers are
critical to ensure optimum performance,
low noise levels and maximum system
reliability. As a general rule, controls at
the front end of a system (source, equal-
izers and other processors) should be set
as high as possible with the amplifier
input sensitivity set as low as possible
while still providing adequate volume lev-
els. Using a high signal level and a low
sensitivity setting will help keep back-
ground noise in the system to a
minimum.

Initially, turn the input sensitivity GAIN
control to its minimum (counter-clock-
wise) position.
1. Reconnect the (–) negative lead to

your vehicle’s battery. Apply power to
the audio system and play a favorite
music track from a CD or tape. (Note:
After the source unit is on, the JBL
badge (on the top panel) will illumi-
nate, indicating the amplifier is on. If
not, check the wiring, especially the
remote connection from the source
unit. Also refer to “Troubleshooting”
on page 7.)

2. On the source unit, increase the volume

control until it is approximately 3/4 of
its maximum output level. Slowly
increase the Input Sensitivity control
(clockwise) toward three o’ clock and, at
the same time, listen to the quality of
the reproduced sound. 

At some point, you’ll hear distortion
on the music peaks. Stop the adjust-
ment and turn it back slightly. This is
the maximum undistorted output level
of your system, and should not be
exceeded during use. 

3. After adjusting the level of the main

speakers in your system, you should
adjust the remaining channels (if you
are using a DA3504 or a multi-amp 
system) for the desired system bal-
ance. You’ll find this easiest to do by
adjusting the channels in the following
order: 1) front speakers, 2) rear speak-
ers, 3) subwoofer. Elaborate, multi-
channel systems may be too complex
to adjust. Your local JBL installation
specialist is the best person to help
with such adjustments. 

DA OM  7/14/98 11:38 AM  Page 5

For your convenience, we’ve included
several application diagrams to help you
plan your own system installation.
Figures 1 through 4 show how to config-
ure the Decade Series power amplifiers
for stereo, bridged-mono and tri-mode
operation. 

(Note: For simplicity, figures do not
show power, remote and input connec-
tions.)
Figure 1. This wiring diagram shows a
DA4002, DA6502 amplifier set to stereo
to drive a pair of full-range speakers.
Figure 2. This wiring diagram shows a
DA1002 amplifier set to bridge mode
(mono) to drive a single subwoofer.
Figure 3. This wiring diagram shows a
DA4002, DA6502 amplifier set for tri-
mode operation. For a desired crossover
frequency, use the chart on page 4 to
select an inductor for the subwoofer,
and corresponding capacitors for left
and right speakers.
Figure 4. This wiring diagram shows a
DA3504 set to drive a pair of 5-1/4" 
2-way speakers with the two front 
channels, and the rear channels set
to drive a single subwoofer in bridge
mode.

6

+

–

+

–

+

–

–

+

15

+

–

+

–

+

–

–

+

20

+

–

–

+

+
+

–

–

+

–

–

+

20

20

+

+

–

–

+

–

+

–

+

–

+

–

+

–

+

–

+

–

+

–

+

–

+

–

–

+

30

+

–

+

–

–

–

+

–

DA OM  7/14/98 11:38 AM  Page 6

7

No audio

Low/no remote on voltage

Check connections; turn-test turn-on voltage

Speakers are not connected 

Check wiring; use VOM/DVM to measure speaker coil 

or are blown

resistance

Distorted audio

Input sensitivity is not set properly

See Setting Input Sensitivity on page 5

Audio lacks “punch”

Speakers are wired with 

Check polarity of connections; refer to Applications

wrong polarity

Audio cycles off and on;

A protection circuit is turning 

Verify the following: off electrical system is between

amber protection LED

amplifier off and on

5 ~ 18 Vdc; temperature is not over 194°F (90°C); 

(JBL badge on top panel)

no short circuits; speaker loads are not less than 2 ohms 

is not lit

(4 ohms in mono)

Audio cycles off and on;

GAIN is set too high

Set Input Sensitivity correctly (see page 5)

amber protection LED
(JBL badge on top panel) is not lit

Fuse blows

Incorrect wiring or

Check connections; refer to Applications

short circuit

Declaration of Conformity

Kongevejen 194B 
DK-3460 Birkerød
DENMARK

declare in own responsibility, that the products  

  described

in this owner’s manual are in compliance with technical

 

standard:

EN 55 020/6.1988

Steen Michaelsen

Birkerød. DENMARK. 3/98

Use the following guide to identify
symptoms and solve problems. Make
sure the vehicle’s electrical system is
working properly and power is reaching
the amplifier’s power connector.

DA OM  7/14/98 11:38 AM  Page 7