O w n e r ' s I n s t r u c t i o n s
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 c o m m o n l y 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 J B L 4343 or 4350
bi-amplified studio monitors. In addition, blank cards can be
obtained for construction of crossover networks for other
frequencies.
I n s t a l l a t i o n
The electronic frequency dividing network receives the
program signal from a line level source-preamplifier, studio
console, or portable m i x e r - a n d 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 20ft), isolation
transformers (600 ft: 600 ft) are recommended at each
output to reduce the possibility of radio frequency interference
or h u m . T h e outputs can d18 dB (6.2 V into 600 ft)
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 mid range and low frequency amplifiers. Typical instal-
lations are diagrammed in Figure 1.
Whenever a mid range or high frequency driver is connected
directly to a power amplifier, a series capacitor is recom-
mended 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 J B L 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 J BL studio monitors designed for
bi-amplification already incorporate the required attenuation
capacitors to protect the midrange and high frequency
drivers.
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