P 4040 (serv.man3) - JBL Car Audio User Guide / Operation Manual. Page 3

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• Check clearances on both sides of a

planned mounting surface before drilling
any holes or installing any screws.
Remember that mounting screws can
extend behind the mounting surface. 

• Always wear protective eyewear when

using tools. 

• When routing cables, keep input signal

cables away from power cables and
speaker wires. 

• When making connections, make sure that

each connection is clean, insulated, and
properly secured. Observe the polarity
markings on the rear panel. Refer to the
application drawings to set up the amplifier
for operation in stereo, bridged-mono, bi-
amp, or tri-mode configurations.

• If the amplifiers fuse must be replaced, use

only the same rating and type as a
replacement. Do not substitute another
kind.

(figs. 1, 2, 3, 4, 5, 6,)
1. Pre-amp Level Input Connector – Connects

to line level output from the source unit. 

2. Universal Interface Speaker Level

Connector – Connects to speaker level
output from the source unit. Provides
Common Sense amplifier turn-on when
used with factory radios. (2-channel on 
P-4020, 4-channel on P-4040)

3. Pre-amp Level Output Connector –

connects to other amps or processors in
the signal chain (flat on P-4020, flat or
filtered on P-4040)

4. Speaker Output Connector – (2-channel on

P-4020, 4-channel on P4040)

5. Fuses – P-4020: 20A ATC type P-4040: 30A

ATC type.

6. Power Connector – Connections for 12V +,

Gnd and Rem.

7. Input Mode Switch – Sums left and right

inputs.

8. Input Sensitivity Control – Adjusts input

sensitivity for pre-amp level and speaker
level inputs.

9. Pre-amp Output Selector Switch – Selects

input path for pre-amp output. Output can
be summed from front and rear inputs
with no filter, or filtered by the front or rear
crossover.

10. Rear Channel Input Selector – Selects rear

channel input between front input and
rear input.

11. Crossover Selector – Determines whether

the crossover is a High Pass filter (HP), a
Low Pass filter (LP), or unfiltered (Flat).

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