Peavey CS 800X - Cooling and Operation Modes; Bridge Mode Explained; DDT Compression System

This will prevent possible overheating of any sensitive equipment by the hot air rising from the
power amplifier. As a general rule, most home and studio requirements will never cause high
speed fan operation. If it does however, this may indicate that you have not taken the necessary
steps to provide adequate cooling. Remember, closed up in a cabinet, the CS-800X will have
severe cooling problems, even at low power levels. Again, inadvertent short circuit or
sustained overloaded usage could also cause temporary thermal shutdown. Also, most home
wiring and electrical circuits are only 15 AMPS. Two CS-800X’s could cause a power panel
15 AMP circuit breaker to trip if a severe overload occurs.
BRIDGE MODE:
The bridge mode on stereo amplifiers is often misunderstood as to the actual operation and
usage. In basic terms, when a two channel amplifier is operated in the BRIDGE mode, it is
converted into a single channel unit with a POWER RATING equal to the sum of both
channels' power ratings, at a LOAD RATING of twice that of the single channel rating. In
this case, the CS-800X is rated at 600 watts RMS per channel into 2 ohms. The BRIDGE
RATINGS is 1200 watts RMS into 4 Ohms (minimum load). Bridge mode operation is
accomplished by placing the mode switch in the “BRIDGE” position, connecting the positive
speaker lead to Channel A RED binding post, negative speaker lead to Channel B RED
binding post, and using channel A as the input channel. All channel B input functions are
defeated.
Another application for BRIDGE mode operation is to drive sound distribution systems in
very large public address applications. In this mode, the CS-800X power amplifier can
actually drive 70 volt systems directly without using expensive matching transformers. The
real advantage of such an approach is primarily cost. 70 volt distribution systems are very
common in domestic applications where large numbers of relatively small loudspeakers are
used for BACKGROUND MUSIC AND PAGING. Such systems require the use of 70 volt
TRANSFORMERS at each loudspeaker. Another common use for the BRIDGE mode is in
SUBERWOOFER applications where very high power levels are required to reproduce
extreme low frequencies. Such enclosures usually contain 2 or 4 loudspeakers to handle the
power levels involved. For bridge mode usage, the enclosure impedance must be 4 or 8
ohms; never below 4 ohms! Also make sure the enclosure can handle 1200 watts reliably.
DDT:
Peavey’s patented DDT compression circuitry enables the sound man to maximize the
performance of the amplifier/speaker combination by preventing the power amp from run¬
ning out of headroom . This compression system is activated by a very unique circuit that
senses signal conditions that might overload the amplifier and activates compression (reduces
the amp gain) when clipping is imminent. Threshold of compression is then clipping itself,
and no specific threshold control is used. This technique effectively utilizes every precious
watt available for the power amplifier to reproduce the signal, while at the same time mini¬
mizes clipping and distortion, and thus significantly reduces the potential of loudspeaker
degradation and damage. The DDT system is an automatic, hands-off approach to the
problem of power amplifier clipping. Since the CS-800X power amplifier now uses a circuit
breaker for over-current protection, the DDT compression system plays an even more impor¬
tant roll in continuous performance by preventing each channel from clipping and overload.
Continuous operation at clipping can cause the circuit breaker to trip, but with the DDT
activated, this problem is minimized. For this reason, you should always have the DDT