JBL S-412-P Service manual

STUDIO SERIES

S412P

4 - way POWERED SPEAKER SYSTEM

SERVICE MANUAL

JBL Consumer Products
250 Crossways Park Dr.

Woodbury, New York 11797

Rev 0 – 2/2000

- CONTENTS -

GENERAL SPECIFICATIONS………………...………………...………………..2

AMPLIFIER SPECIFICATIONS……………………………….……...…………..3

SET-UP GUIDE………..………………….…………………………..…..………..4

CONTROLS……………………………….……………..………………..………..6

TROUBLESHOOTING…………..…………………………...……..……………..7

MECHANICAL PARTS LIST………………………….…………………………..8

CABINET EXPLODED VIEW……………………………………………………..9

WIRING/PASSIVE SCHEMATIC DIAGRAMS……..……..……………………..10

AMPLIFIER EXPLODED VIEW………………..…..…...……….………………..11

BLOCK DIAGRAM…………………………………………………..…………….12

INTEGRATED CIRCUIT DRAWINGS………….…………..…………………....13

ELECTRICAL PARTS LIST……………………………….……………………….14

P. C. BOARDS……………………………..…………….……………………..…..17

SCHEMATICS…..………………..……………..……….…….…………….……..19

PACKAGING…………………………………………….……………………..…..22

S412P

GENERAL ACOUSTIC & ELECTRICAL SPECIFICATIONS

• Nominal Impedance 8 ohms

• Max Amp Power 250 watts*

• Frequency Response 32Hz – 20kHz

• Sensitivity 91 dB (1 watt @ 1 meter)

• Crossover Frequency 200Hz, 850Hz, 3500Hz

• Subwoofer Amplifier Output 200 watts

AURAL SWEEP TEST SPECIFICATIONS:

A. System Aural Sweep Test 6.0V Input 20 Hz to 20 kHz
B. L.F. Aural Sweep Test 6.0V Input 20 Hz to 500 Hz
C. M.B.F. Aural Sweep Test 5.0V Input 100 Hz to 1 kHz
D. M.F. Aural Sweep Test 4.0V Input 500 Hz to 4 kHz
E. H.F. Aural Sweep Test 2.83V Input 3 kHz to 20 kHz

PHYSICAL SPECIFICATIONS

Enclosure dimensions

Weight

*The maximum recommended amplifier power rating will ensure proper system headroom to
allow for occasional peaks. We do not recommend sustained operation at these maximum
power levels.

Occasional refinements may be made to existing products without notice but will always meet
or exceed original specifications, unless otherwise stated.

: 44 x 16 x 13 3/8” (H x W x D)

1118 x 406 x 340mm

86lbs./39.1kg Each

2

PRODUCT: JBL S412P

(

)

p

d

S412P AMPLIFIER SPECIFICATIONS

3

LINE VOLTAGE Yes/No Hi/Lo Line Nom. Unit Notes

Parameter Specification Unit
Amp Section

Type (Class AB, D, other) G n/a
Load Impedance (speaker) 4 Ohms

Rated Output Power 150 Watts
THD @ Rated Power 0.1 %
THD @ 1 Watt 0.3 %
DC Offset 10 mV-DC

Damping factor >150 DF

Input Sensitivity

Input Frequency 30 Hz
LFE input 1.05 Vrms
Speaker/Hi Level Input 23.66 Vrms

Signal to Noise

SNR-A-Weighted 100 dBA
SNR-unweighted 70 dBr
SNR rel. 1W-unweighted 65 dBr

Residual Noise Floor 1 mVrms

Residual Noise Floor 1.5 mVrms

US 120vac/60Hz Yes 108-132 120 Vrms Normal Operation

EU 230vac/50-60Hz Yes 207-264 230 Vrms Normal operation, MOMS required

QA Test

Limits Conditions Notes

>75

max

n/a
n/a

Nominal Z-curve required

130

1 input driven

1

22k filter

0.5

22k filter

20

@ Speaker Outputs

100

Measured at amplifier board

50

Measured at speaker cable

30

Nominal Freq.

±2dB

To 140 Watts

±2dB

To 140 Watts

90

relative to rated power A-Weighting filter

70

relative to rated power 22k filter

60

relative to 1W Output 22k filter
Volume @max, using RMS reading

5

DMM/VOM (or A/P)
Volume @max, w/ A/P Swept
Bandpass Measurement (Line
freq.+ harmonics)

4

Class D Preferred...Sink required for Class AB

Measured at the speaker connector. 130 Watts
@ THD < 0.08 % @ 50 Hz

Input Impedance

Speaker/Hi Level Input 10k ohms

Filters

S

eaker in LP 2nd order fixe
Subsonic filter (HPF)
LFE Low pass 2nd order Fixed

Limiter

THD at Max. Output Power

Features

Auto - On selection switch YES -­LED On-Off switch YES -­Volume pot Taper (lin/log) LOG --

Input Configuration

Line In LFE
Spkr/Hi Level In YES --

Signal Sensing (ATO)

Auto-Turn-On (yes/no) YES
ATO Input test frequency 30 Hz
ATO Level LFE Input 4 mV
ATO Level Speaker in 100 mV

ATO Turn-on time 5 ms

Auto Mute/ Turn-OFF Time 15 minutes

Line Input 20k ohms

Fixed

n/a n/a functional

--

YES --

n/a

Nominal

n/a

Nominal

See AP curves

LFE input driven only See AP curves

Maximum Output Power Maximum THD as a result of limiting.

functional
functional
functional

functional Single RCA jack

functional

functional
functional
functional
functional

functional

Auto - on selection switch in Auto

Amp connected and AC on, then
input signal applied
T before muting, after signal is

17

removed

"
"
"

See AP curves

Refer to ATO section
Dual LED indicator
A Taper

Maximum

SPEAKER CONNECTIONS

– +– +

– +

Speaker Outputs

LEFT

RIGHT

– +

CONNECTION TIPS

Speakers and electronics
terminals have corre­sponding (+) and (–)
terminals. It is important to
connect both speakers
identically: (+) on the
speaker to (+) on the

SPEAKER-LEVEL CONNECTIONS

amplifier and (–) on the
speaker to (–) on the
amplifier. Wiring “out of
phase” results in thin
sound, weak bass and a
poor stereo image.

Your S412P speakers
should be connected to
your receiver in two ways
(at speaker level and line
level) in order to achieve
the best performance,
especially when listening
to program material
recorded in digital 5.1
formats, such as
Dolby** Digital and DTS.
Connect the left-front and

4

right-front speaker
terminals on your receiver
or amplifier to the 5-way
binding posts on the back
of each S412P speaker.
Remember to maintain the
correct polarities (“+” to
“+” and “–” to “–”). The
S412P uses a red binding
post for “+” and black for

®

“–”. These connections

will provide full-range

sound to all four
transducers, and you
should ALWAYS make
these connections.
If your receiver or
amplifier does not have a
line-level subwoofer
output, then you do not
need to make any other
connections, and you
should skip to the section
titled “Amplifier Controls.”

RECEIVER/AMPLIFIER

LEFT S412P RIGHT S412P

LEFT

RIGHT

Y-Connector

(not included)

LFE IN LFE IN

SUBWOOFER OUT

LINE-LEVEL CONNECTIONS

Each S412P speaker is also
equipped with a line-level
Low-Frequency Effects
(LFE/Subwoofer) input for
superior performance with
digital 5.1 surround
formats. The .1 LFE
channel contains
additional low-frequency
information not found in
the left- and right-front
channels. The LFE input
works with the full-range
speaker-level input to
provide the dynamics and

effects that your favorite
filmmakers intended.
You will need to use a
Y-Connector (not included)
with one male connector
and two female connectors
to connect the line-level
subwoofer output on your
receiver/amplifier to the
LFE/Subwoofer inputs on
the S412P speakers. Plug
the male connector into
the subwoofer output on
your receiver or amplifier,
and connect each of the

two female connectors
to extension RCA patch
cords. Then plug each
patch cord into the
LFE/Subwoofer input of
the left and right S412P
speakers. Note: If your
receiver has separate
left and right line-level
subwoofer (or LFE) output
jacks, you do not need to
use a Y-Connector.

5

AMPLIFIER CONTROLS

MANUAL

LFE LEVEL

Min Max

AUTO

ON

OFF

S412P

LFE IN –

ON

OFF

GREEN “ON”LED

POWER ON/OFF

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

“WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK,
DO NOT EXPOSE THIS APPLIANCE TO RAIN OR MOISTURE.”
“AVERTISSEMENT: POUR PRÉVENIR LES RISQUES D’INCENDIE OU
DE CHOC ELECTRIQUE, EVITER D’EXPOSER CET APPAREIL A LA
PLUIE OU A L’HUMIDITE.”

This area is designed to become quite warm

during normal operation.

LFE Level Control: Allows
you to adjust the volume of
the low-frequency effects/
subwoofer channel to suit
your room acoustics or
tastes. However, it only
affects the LFE signal. If
you are not using the LFE
input, the LFE level control
will not operate.

Configuring Your Receiver:

You should choose the
“Large” or “Wide” option
for the left- and right-front
speakers so that full low­frequency information will
be sent to the S412P
speakers. Make sure that
you also configure your
receiver for “Subwoofer
On” or “LFE On.” In this
case, the LFE/Subwoofer
signal will

consist only of
the .1 (bass)
LFE signal level can be
adjusted by using the
LFE level on the S412P
amplifier panel. For initial
setup, you should set the
level controls on both
speakers at minimum
(full counterclockwise
rotation). With 5.1 source
material playing, advance
the level controls on each
speaker slowly until the
desired amount of effects
channel is present. This
is a rather subjective
adjustment and should be
made using a variety of
program materials.

If you choose, you can use
the “Small” or “Narrow”
setting on your receiver.
In this case, all of the
information below 80Hz
will be fed to the LFE/
Subwoofer input on the

6

channel. The

S412P. Now the level
control operates through­out the entire bass
spectrum below 80Hz, not
just within the .1 channel
portion. This configuration is
generally unnecessary but,
in certain room-placement
conditions, it allows greater
bass-level control.

Power Switches: The main
“Power” switch is simply
marked “On” and “Off.”
Turn this switch on to
commence operation of
the powered amplifier
after you have plugged the
power cord into an AC
outlet. The second switch
is labeled “On/Off” and
has two positions. Placing
the switch in the “Auto”
position puts the amplifier
in Standby mode. In this
mode the speaker will be
able to automatically
sense an incoming signal,
which will trigger it to turn
fully on. The speaker will
also automatically switch
itself back into Standby
mode after approximately
10 to 15 minutes have
passed without its sensing
a signal. We recommend
that you leave this switch
in the “Auto” position for
most applications. If you
will be away from home or
not using your speakers
for an extended period of
time, you should turn the
speakers off by using the
main power switch. The
Manual position will bypass
the auto-sensing feature
and leave the amplifier on
until turned off with the
main switch or returned to

auto sensing by choosing
the auto position.

LED Indicators: When your
speaker is turned on but is
not receiving a signal, the
LEDs glow red to let you
know that your speaker is
plugged in. When the
speaker is receiving a
signal, the LEDs glow
green. We have provided a
convenient “Green ‘On’
LED” switch on the back
panel to allow you to shut
off the front LEDs should
they interfere with your
enjoyment of a movie. This
switch has no effect when
the LEDs are in red mode.