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.
,5. 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.
6.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 1200X, 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
