Jbl 5234 a owners manual

Page 1

JBL

5234A
INSTALLATION ,
AND SERVICE
MANUAL

Page 2

TABLE OF CONTENTS

ARCHITECTURAL SPECIFICATIONS

PRODUCT SPECIFICATIONS
Electrical
Physical

INSTALLATION
Installation of Standard Crossover Frequency Modules
Programming the Internal High-Pass Filters
Mounting
Input Connections
Output Connections
Use Floating or Balanced Cables for Longer Runs
AC Power Connection and Line Voltage Conversion
Protection of Compression Drivers

SETUP AND OPERATION
General Applications
Typical Systems Employing the 5234A
A Safety Procedure for Initial Powering Up of The System 14

tototo mummmofim-fi-b wrote N

Level Control Adjustment 14
System Phasing and Signal Polarity 14
Selecting the Low Frequency High-Pass Filter Options 16
Blank Crossover Card Assembly 16
PARTS LIST 13
SCHEMATIC DIAGRAM 19

LIST OF ILLUSTRATIONS

Figure Description
1 Total Harmonic Distortion 3
2 5234A Low Frequency Cutoff Characteristics 3
3 Screw Removal to Lift Off the Bottom Cover 4
4 Identification of Major Components Inside 5234A 4
5 Crossover Card Mounting Alignment 4
6 One of the Two Programming DIP Switches 5
7 DIP Switch Programming and Resultant Low 5
Frequency Cutoff Characteristics
8 Model 5234A Rear Panel 6
9 Using Isolation Transformers to Float the Cable 6
Between 3 5234A Output and an Unbalanced
Load
10 Using an Isolation Transformer to Float (or 7
Balance) the Cable Between a 5234A Output
and a Floating (or Balanced) Load
11 Using an Isolation Transformer to Float the 7
Input Cable to the 5234A
12 Conventional Two-Way System (Passive Network) 9
13 Conventional Three-Way System (Passive Network) 9
14 Dual Channel Two-Way System (Biamplified) 9
15 Single Channel Three-Way System (Triamplifiedl 10
15 Dual Channel Two-Way System with Monaural 1O
Subwooferls)
17 Combining Electronic and Passive Frequency 10
Dividing Networks
18 Wiring Diagram for Biamplified System 11
19 Wiring Diagram for Triamplified System 12
20 Wiring Diagram for Two-Way System with 13
Monaural Subwooferls)
21 12 dB/Octave Blank Crossover Card (JBL 16
Model 52-5120) with Component Designations
22 18 dB/Octave Blank Crossover Card (JBL 16
Model 51 -5130l with Component Designations
Table
1 Maximum Values for Low Frequency 8
Attenuating Protection Capacitors
2 JBL Protection Capacitors for Compression Drivers 8
3 12 dB/Octave Crossover Card Component Values 17
4 18 dB/Octave Crossover Card Component Values 17

WARNING: To prevent fire or shock hazard, do not expose
this unit to rain or moisture.

ARCHITECTURAL SPECIFICATIONS

The electronic frequency dividing network shall it
contain two channels, each with low-level active
filters that separate the program into low and high
frequency bands at designated crossover frequency
points. Each channel shall have a transformerless,
differential amplifier input and separate buffer
amplifiers for its low and high frequency outputs.
Input and output connections shall be made via
either 1/4 inch (6.3 mm) phone jacks or screw
terminals provided on the unit's rear panel.

Crossover frequency selection shall be accom-
plished by internally mounted plug-in circuit
modules, one per channel. Each module shall be
designated with the crossover frequency, printed
in such a position as to be easily read through a
window in the unit's front panel. The designated
crossover frequency shall be the point at which
the slopes of the pass band curves cross, and where
each is 3 dB down from the average pass band
output level; this point shall be within i 10% of
the designated frequency. A variety of modules
shall be available, not only with different crossover
frequency points, but also with 12 dB or 18 dB
per octave filter slopes. Blank plug-in modules shall
be available, allowing for the installation of suitable
capacitors and resistors to achieve custom crossover
frequency points.

In addition, internally switch selectable low
frequency equalization and subsonic filtering shall (x

I

be provided for each channel, enabling low fre» 1
quency response to be optimized while blocking
subsonic energy below the lowest usable speaker
frequency. These dual in line switches shall allow
the following programmable options, all with
12 dB per octave slope rates (except the flat
response setting):

a. Flat frequency response leg, no L.F. cut-

off filter).

b. 20 Hz high pass filter, 0 = 0.707 (Butter-
worth).

c. 20 Hz high pass filter, 0 = 2 (6 dB boost
at 20 Hz).

d. 30 Hz high pass filter, 0 = 0.54.

e. 30 Hz high pass filter, 0 = 0.84.

f. 30 Hz high pass filter, 0 = 2 (6 dB boost
at 30 Hz).

9. 40 Hz high pass filter, 0 = 0.707 (Butter-
worth).

h. 40 Hz high pass filter, 0 = 2 (6 dB boost
at 40 Hz).

The internal switching shall also allow both
channels' low frequency outputs to be combined
into a monaural signal which, with an appropriate
crossover frequency, is suitable for driving a sub»
woofer channel while the high frequency outputs
drive a full-range stereo speaker system.

The unit shall fit in a 44 mm (1-3/4 inch) high a
space in a standard 483 mm (19 inch) equipment t
rack. Recessed front-panel adjustments shall be
provided for the high frequency output level of
each channel. A recessed rear panel slide switch
shall allow operation with nominal 100 to 120 V

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