, 5.
6.
ule. In this case, the associated XLR connector (11) is now unbalanced as per previous
discussion. If desired, the parallel unbalanced phone jack inputs (13) may be used to
supply signal to the crossover module. In addition, whenever the XLR connector on a
particular crossover island is used (either balanced or unbalanced), the crossover input
jacks (13) can be used to patch out full-range signals to other amplifier/speaker systems
that are operating in full range or other biamped systems that require different crossovers.
Care must be taken never to remove or replace a crossover module with the CS 1200X
power switch on. The complex circuitry used in the crossover modules receives bipolar
power through the socket, and removal or replacement could cause severe transients that
can destroy the loudspeaker system. Always turn off the CS 1200X first. As an added
feature, the bipolar power for the crossover islands can be supplied from either channel of
the CS 1200X. Thus, if one channel should shut down for any reason, the redundancy of
the system will maintain operation of the crossovers.
The individual sensitivity controls on each channel play a very important role in the use
of the crossover modules. As such, they represent a signal loss when they are operated at
another setting other than full clockwise (maximum sensitivity). Biamped speaker sys-
tems usually require less signal level for the high-frequency components because they are
generally more efficient. Consequently, a system balance can be achieved by reducing the
high-pass level. This is particularly important on non-Peavey loudspeakers where the
PL-500, PL-800 or PL-1200 crossover modules must be used. These modules are referred
to as “no pad and equalization” types. As such, there is no reduction in high-pass level.
Consequently, the pad must be accomplished using the high-pass channel sensitivity
control. The amount of pad required is always the difference between the efficiency
ratings of the high and low speaker components. Whenever Peavey loudspeakers are
operated using the special crossovers, the sensitivity controls should be set at full-clock-
wise settings (maximum sensitivity) to provide maximum system headroom, since the
correct pad and equalization is already provided in the crossover module itself.
BRIDGE MODE NOTES
1.
The bridge mode on stereo amplifiers is often misunderstood as to actual operation and
usage. In basic terms, when a two-channel amplifier is operated in the bridge mode, it is
converted to a single-channel unit with a power rating equal to the sum of both channels’
continuous power ratings, at a load rating of twice that of the single-channel ratings. For
the CS
the bridge ratings are now 1200 W RMS into 8 ohms and 1800 W RMS
into 4 ohms (minimum load). Bridge-mode operation is accomplished by placing the
mode switch (10) in the bridge position, connecting the load between the red binding
posts of each channel, and using Channel A as the input channel. All the input functions
of Channel B are defeated. What actually happens from a technical standpoint is that
Channel B is supplied an input signal that is equal in level but is 180 degrees out of phase
from that of the Channel A input signal (i.e., when Channel A’s signal is positive, Chan-
nel B’s signal is negative, and vice versa). Thus, the load (which is connected between the
channel outputs) sees the sum of the output voltages of both channels (which is then
twice that of the single channel), and this load must be 4 ohms or greater.
2.
For proper bridge-mode operation, both wires of the output must “float” above ground. If
either wire becomes grounded, this will present a short circuit to the associated channel
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