P 4040 (serv.man3) - JBL Car Audio User Guide / Operation Manual. Page 2

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• 4, 3 or 2 channel Operation (P-4040) 2 or

One channel Operation (P-4020)

• Simultaneous stereo and mono Operation
• Built-in 12dB/oct Electronic Crossover
• Balanced Differential Input 
• Pre-amp outputs (filtered on 4040)
• Oversized Floating Rail Mosfet Power

Supply

• Universal Interface
• Common Sense Turn-on
• Variable Input Sensitivity (250mV-4V)
• Fully Complementary, Direct Coupled

Discrete Power Amplifier Circuitry

• Gold-Plated Power, Input and Output

Connectors

• 2-Ohm Stable (stereo)
• JBL badge lights when amp is operating,

and flashes when protection circuit is
activated

• Made in USA

The JBL P-4020 is a 2-channel power
amplifier that offers stereo, bridged-mono, or
tri-mode operation, and is rated at 40 watts
(rms) per channel into a 4-ohm load. In a
bridged-mono configuration, it can deliver up
to 120 watts (rms) for the same load. The JBL
P-4040 is a 4-channel version with the same
power ratings. Both amplifiers also feature:
• 2-ohm operation, rated at 75 watts (rms) per

channel 

• A bridge/stereo switch for fast system setup 
• A built-in 80 Hz, 12 dB-per-octave electronic

crossover 

• Individually selectable high- and low-pass

filters (with through-pass) for amplifier and
auxiliary outputs

• An amplifier input sensitivity control to

match a wide range of input signal levels
from 250 mV to 9 V

• Universal Interface allows easy connection

of any radio.

• Common Sense Turn-On uses the amplifiers

speaker level inputs to turn on automatically
by sensing dc from the radio's BTL output,
thus freeing the remote terminal for use in
turning on other amplifiers in the system

• Five protection levels guard against over-

voltage, under-voltage, over-power, over-
temperature, and over-current situations

• 2-color LED array indicates green when

power is on and orange when protection is
activated 

• Industrial-grade, gold-plated, pre-wire and

plug-in connectors for an easy-to-install,
high-quality interface

• Transparent control cover to deter

tampering yet provide a clear view of
installation settings

• Built-in automotive type fuse to protect the

amplifier  

• Unibloc chassis provides improved heat-

sink capacity and exceptional RFI shielding
characteristics

To attain maximum amplifier performance,
we encourage you to read the remaining
pages before installing and operating your
new JBL Power Series Amplifier. Especially
review the Applications section for ideas on
designing and expanding your system. Also,
save these instructions for future reference.
IMPORTANT: Installation of automotive
stereo components can require extensive
experience in performing a variety of
electrical and mechanical procedures.
Although these instructions explain how to
install a JBL Power Series Amplifier in a
general sense, they do not show the exact
installation methods for your particular
vehicle. If you do not have the experience, do
not attempt the installation yourself; instead
ask your Authorized JBL Car Audio Dealer
about professional installation options.

This JBL product is made with our ongoing
dedication to creating the best consumer
audio products possible. As a result, you can
expect your new JBL Power Electronics Series
Amplifier to provide you with many years of
listening enjoyment.
All JBL Automotive Products carry a limited
parts and labor warranty (see the enclosed
warranty card), so retain the bill of sale to
protect your purchase and to aid us with any
service-related questions you may have.

• The JBL P-4020 (or P-4040) has five levels of

circuit protection that monitor the amplifier
and will shut it down if the electrical system
voltage drops below 5 Vdc or exceeds 
18 Vdc, temperatures are above 194°F (90°C),
short circuits occur, or current draw exceeds
product specifications. For best performance,
check the intended mounting site to make
sure the operating environment does not
create conditions that will trigger circuit
protection.

• Prior to installation, turn off all audio systems

and other electrical devices. Also disconnect
the (–) negative lead from the vehicles
battery.

• At the installation site, locate and make a

note of all fuel lines, hydraulic brake lines,
and electrical wiring. Use extreme caution
when cutting or drilling in and around these
areas.

for purchasing your new JBL Power

Series Amplifier. Power Series amplifiers
feature the latest advances in discrete circuit
topology ensuring low distortion and
superbly clean and clear sound quality. In
addition to RCA type pre-amp inputs, Power
Series amplifiers feature Universal
Interface™, designed to facilitate integration
with factory installed audio systems for
distortion free performance that rivals
conventional pre-amp connections. Included
in the Universal Interface circuit is Common
Sense™ turn-on. Common Sense turn -on
senses the common-mode voltage present
on the speaker outputs of factory and
aftermarket radios, turning on the amplifier
without a separate remote wire. All Power
Series amplifiers feature built-in electronic
crossovers and pre-amp outputs for easy
system expansion without requiring
outboard processors. Housed within the
sleek, extruded aluminum frames, you'll find
the latest advances in circuit topology, along
with user conveniences like a wide-range
input sensitivity control, auxiliary outputs,
and a built-in electronic crossover. With
features like these and more, you can quickly
try out a variety of system ideas, and
because the P-4020 and P-4040 belong to a
related product family, you're assured future
expansion will look as good as it sounds.