JBL - 5233 - Amplifier
Manufacturer:
Equipment:
5233
Date:
1978
Category:
Group:
Sub Group:
Information
Owner’s Instructions
The
5233 and
5234 are designed for use with studio monitor
or sound reinforcement loudspeaker systems where
bi-amplification or tri-amplification is desirable. The 5233
(single channel) and
5234 (dual channel) feature
differential high impedance inputs, unity gain in the
passband, and unbalanced low impedance outputs. The 5233
will provide a single channel crossover. The
5234 provides
two separate channels with independent crossover action (as
in a stereo installation).
The power switch and pilot light for the unit and a high
frequency level control for each channel are located on the
front panel for easy access. The crossover frequency at
which each channel is operating is indicated through a front
panel window. A voltage change switch is located on the rear
panel. Either model can be mounted in one EIA standard rack
space.
Crossover cards are available for most commonly used
frequencies. Filter slopes are 12 dB or 18 dB per octave
with high and low frequency output attenuated 3 dB at the
crossover point. Cards are also available with the specific
crossover characteristics required for the JBL 4343 or 4350
bi-amplified studio monitors. In addition, blank cards can
be obtained for construction of crossover networks for other
frequencies.
Installation
The electronic frequency dividing network receives the
program signal from a line level source preamplifier, studio
console, or portable mixer-and separates the signal into
high and low frequency bands. Outputs from the network feed
the appropriate power amplifiers, which in turn drive their
respective loudspeaker system components. Input connections
may be balanced or unbalanced, output con-
nections are unbalanced; shielded cable is required. If
output cable lengths are greater than 4.5 to 6 m (15 to 20
ft), isolation transformers (600 Cl 600 Q) are recommended
at each output to reduce the possibility of radio frequency
interference or hum. The outputs can deliver +18 dB (6.2 V
into 600 Q) and will drive the line inputs of conventional
amplifiers. Two or more power amplifiers can be driven from
each output.
The
5234 dual channel network can be used to tri-amplify a
loudspeaker system by connecting the low frequency output of
channel 2 to the input of channel 1. (Twist two unshielded
wires together or use shielded cable for this connection.)
The channel 1-outputs can then be used to drive the midrange
and low frequency amplifiers. Typical installations are
diagrammed in Figure 1.
Whenever a midrange or high frequency driver is connected
directly to a power amplifier, a series capacitor is
recommended to attenuate unwanted low frequency “on-off"
switching transient signals which can damage the driver.
It is possible to construct a system using an electronic low
frequency transition and a conventional passive network for
the midrange or high frequency crossover. The JBL 4350
Studio Monitor, diagrammed in Figure 2, is such a system. If
a pair of 4350s are to be used, a single
5234 can
accommodate both systems. Note that the passive, high level
frequency dividing networks used in all JBL studio monitors
designed for bi-amplification already incorporate the
required attenuation capacitors to protect the midrange and
high frequency drivers.
Service manual
Manual type:
Service manual
Pages:
16
Size:
7.0 MB
Language:
english
Revision:
Manual-ID:
Date:
January 1978
Quality:
Scanned document, all readable.
Upload date:
Sept. 24, 2017
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