Peavey CS 800X User manual

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PROFESSIONAL STEREO POWER AMPLIFIER
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The world famous CS® 800 power amplifier has now been changed to the new CS® 800X with
new extended performance, providing impressive new two ohm output power capability while
still maintaining the current 4 and 8 ohm ratings and awesome industry standards for power
bandwidth, slew rate, and distortion specifications.
Following is the new extended specs:
420 W RMS into 4 ohms...600 W RMS into 2 ohms (per channel)
840 W RMS into 8 ohms... 1200 W RMS into 4 ohms (bridged)
DDTTM compression with LED indicators and defeat switch
Slew' Rate: 40 V/microsecond. stereo mode, each channel
Power Bandwidth: 10 Hz to 50 KHz @ 4 ohms, rated power
Total Harmonic Distortion: Less than 0.03%, rated power
Hum and Noise: 100 dB below rated powder, unweighted
All the current features of the old units have been retained, including Peavey's patented DDT "
(Distortion Detection Technique) Compression Circuitry, and the very flexible back panel
patching capabilities. The two speed fan cooling system has been improved to provide addi¬
tional cooling, when needed, for the tw'o ohm load conditions.
FEATURES
• Automatic two-speed fan cooling system/tunnel
• Independent channel thermal/fault protection
• Transient free turn-on/off operation (relay)
• One recessed crossover “island” socket for plug-in modules
• Two recessed balanced input transformer sockets for PL-2’s
• Single XLR & dual phone plug inputs each channel
• Phone plug inputs are QUASI-ELECTRONIC BALANCED
• XLR input can be QUASI-ELECTRONIC BALANCED (push switch
out)
• XLR input can be transformer balanced (push switch in)
• Dual phone plug and 5 way binding post outputs each channel
• DDT activation LED & power LED each channel
• Calibrated/detented input attenuator control each channel
• Rear panel DDT defeat & bridge mode select slide switches
WARNING!
For uptiinum performance and reliability DO NOT PRF.SRNTTHE AMPLIFIER WITH A SPEAKER LOAD OF LESS THAN 2 OHMS, OR A
COMBINATION OF SPEAKERS THAT TOGETHER ARE LESS THAN 2 OHMS!
Lising one speaker, it must be rated at 2 ohms minimum.
Using two speaker, they must be rated each at 4 ohms minimum.
Using three speaker, they must be rated each at 8 ohms minimum.

DDTT^’ ACTIVE LED (1)
Illuminates when DDT Compression is taking place. With the ENABLE/DEFEAT switch in
the DEFEAT position, the LED indicates when clipping distortion is occurring.
POWER LED (2)
Illuminates when AC power is being supplied to the amp, and the associated channel is opera¬
tional. Illumination is delayed slightly during the power-up cycle due to the transient suppres-
sion/lhermal fault circuitry. If either channel were to experience fault conditions or to exceed
the safe operating temperature limits, then that channel will shut down, and the associated
power LED will go out, indicating such conditions exist. Also, whenever the BRIDGE mode
is selected, the power LED on channel B is defeated (OFF), just as if there were a fault condi¬
tion on channel B. This provides a positive indication that the CS-800X is in bridge mode.
INPUT SENSITIVITY (3)
Maximum input gain (minimum sensitivity rating) is achieved at the full clockwise setting.
This setting yields maximum mixer/system headroom. A setting of less than one full clockwise
turn will yield lower system noise at the expense of mixer/system headroom. Calibration
indicates sensitivity in dB V necessary to attain the full available output power rating.
POWER SWITCH (4)
Depress to “On” position to turn on.

CHANNELA
HIGH Z INPUT JACKS (5)
Two parallel (bridged) input jacks are provided. This allows for one to be used as a conven¬
tional input, and the other to be used simultaneously as a “line out” to connect to another
input jack on this amplifier or other amps/equipment. These 1/4” jacks are not “chassis
grounded” and when used will provided a QUASI-BALANCED input capability due to a
unique “ ground loop” elimination circuitry associated with the input. This feature will nor¬
mally allow “hum free” operation when relatively short 1/4” cable patches are made between
the various jacks on this amp and other jacks on equipment that share the same
rack with this amp. This QUASI-BALANCED capability is automatic, and it can not be re¬
moved from the system's circuitry.
LOW Z INPUT (6)
A conventional three-pin female XLR input jack is provided and may be used as the channel A
input. When the (PL-2) line balancing transformer is not used, this XLR input becomes
QUASI-BALANCED with pin #3 as the positive input (connecting to the tip of the 1/4" input
jacks above), pin #2 as the negative input (connecting to the floating sleeve of the 1/4" input
jacks above), and pin #1 going to chassis ground. When the (PL-2) line-balancing transformer
is used, this XLR input becomes fully TRANSFORMER-BALANCED (Pin #3 positive, pin
#2 negative, pin #1 ground). (See the PL-2 SELECTOR SWITCH section for details on related
settings)
PL-2 SELECTOR SWITCH (7)
This switch is to be used in conjunction with the PL-2 transformer to allow the LOW Z INPUT
to function with or without a PL-2 module being inserted in the receptacle. A similar function
was performed by using a PL-1 module inserted in the PL-2 receptacle on older amplifier
models. The “OUT” position of this switch selects the QUASI-BALANCED mode of opera¬
tion for the LOW Z INPUT (XLR jack), and routes the input signal directly to the HI Z INPUT
JACKS. In this position the HI Z INPUT JACKS may be used as outputs after the LOW Z
INPUT to allow patching this signal to another input on this amp. Normally, in this switch
position, a (PL-2) transformer is not present (“OUT”) in the transformer receptacle; however,
if one were “IN” the receptacle, the LOW Z INPUT would still be QUASI-BALANCED. It
becomes TRANSFORMER BALANCED only when the IN switch position is selected. Notice
this is a very effective means to “test” for the necessity of a line-balancing transformer. The
“IN” position of the switch routes the input signals from the XLR jack, through the (PL-2) line¬
balancing transformer, thus selecting the TRANSFORMER BALANCED mode of operation
for the LOW Z INPUT. In this position the HI Z INPUT JACKS may be used as outputs after
the line balancing transformer to patch the signal to another input jack on this amplifier or other
amps/equipment. If the “IN” position is selected without a (PL-2) line-balancing transformer
“IN” the receptacle, the LOW Z INPUT will be rendered inoperable.
TRANSFORMER RECEPTACLE (8)
This receptacle only receives the optional (PL-2) line-balancing transformer. When conditions
exist that demand the usage of a TRANSFORMER-BALANCED XLR CONNECTOR at the

tions exist that demand the usage of a TRANSFORMER-BALANCED XLR CONNECTOR
at the input of channel “A”, the (PL-2) transformer must be put here, the selector switch
must be in the “IN” position.
SPEAKER OUTPUTS (9)
Two 1/4" jacks and 5 way binding post speaker output terminals are provided. All these
outputs are in parallel, hence the speaker connection cables can be terminated with 1/4"
phone plugs, banana plugs, or stripped wires for use in the binding post terminals. For
sustained high power applications, the use of the binding post terminals are recommended;
however, care must be exercised to assure correct speaker phasing. Regardless of what
connections are used, the typical parallel speaker load should always be limited to 2 ohms
per channel or 4 ohms BRIDGE mode for any application. Operation at loads of 4 ohms per
channel or 8 ohms BRIDGE mode is more desirable for sustained operation applications due
to the fact that the amplifier will run much cooler at this load. Operation above 4 ohms per
channel, and even open circuit conditions, can always be considered safe; however, sustained
operation at loads below 2 ohms could result in temporary amplifier shut down due to the
thermal limits and/or the internal fault circuitry. When used in BRIDGE mode the positive
speaker lead should be connected to Channel A RED BINDING POST and the negative
speaker lead to Channel B RED BINDING POST.
CHANNELB
NOTE: On this channel a crossover module “ISLAND” has been provided to allow a
PL-MODULE ELECTRONIC CROSSOVER to be used to perform a “BIAMP” function.
Associated with this island are dual crossover input jacks, high and low output jacks, and a
crossover receptacle. These will be discussed further in following sections, but please note
that the channel B patches are somewhat different from those of channel A.
HIGH Z INPUT JACKS (10)
Two parallel input jacks are also provided in this channel, allowing the flexibility of the Y-
cord capability here as well. These jacks are also not chassis grounded and will provide a
QUASI-BALANCED input capability. Both of these input jacks are “switching” type, where
usage of either of these jacks disables the signal feed from the LOW Z INPUT circuitry
associated with this channel. This is necessary to allow this input to be patched from the
appropriate electronic crossover output jack and then use the LOW Z INPUT circuitry as the
input for the electronic crossover. This feature prevents these jacks from being used as
outputs from the LOW Z INPUT circuitry, as was possible with the Channel A input jacks.
LOWZINPUT(ll)
A conventional three-pin, female XLR input jack is also provided here, and it can be used as
the channel B input, provided the HI Z INPUT jacks are not being used. When the (PL-2)
line-balancing transformer is not used, this XLR input becomes QUASI-BALANCED with
the exact same pinout arrangements as discussed for channel A. When the (PL-2) line balanc¬
ing transformer is used, this XLR input becomes fully TRANSFORMER-BALANCED,
again with the same pin polarities as those presented for channel A. (See the PL-2 SELEC¬
TOR SWITCH manual section for details on related settings). The output of this low Z

circuitry is always connected to the CROSSOVER INPUTS and thus this low Z feature can
be used as the input for the crossover module if the application demands the use of an XLR
connector.
PL-2 SELECTOR SWITCH(12)
The function of this switch is identical to that of channel A function. The “OUT” position of
this switch selects the QUASI-BALANCED mode of operation for the LOW Z INPUT (XLR
jack) and routes this input signal directly to the HI Z INPUT jacks if these Jacks are not in
use. Since this signal is also routed to the CROSSOVER INPUT jacks, now these jacks may
be used as outputs after the LOW Z INPUT to allow patching this signal to another input on
this amplifier.
Similarly, the “IN” position of the switch routes the input signals from the XLR jack through
the (PL-2) line-balancing transformer thus selecting the TRANSFORMER-BALANCED
mode of operation for the LOW Z INPUT. In this position the CROSSOVER INPUTS may
be used as outputs after the line-balancing transformer to patch the signal to another input
jack on this amplifier or other amps/equipmenl. Again selecting the “IN” position without a
(PL-2) line-balancing transformer IN the receptacle will render the LOW Z INPUT inoper¬
able, and this switch can be used to test the “effectiveness” of TRANSFORMER BALANC¬
ING.
TRANSFORMER RECEPTACLE(13)
This receptacle only receives the optional (PL-2) line-balancing transformer. When condi¬
tions exist that demand the usage of a TRANSFORMER-BALANCED XLR INPUT at the
input of channel “B”, or at the input of the PL-MODULE ELECTRONIC CROSSOVER
when BIAMPING then the (PL-2) transformer must be put here, and the selector switch must
be in the “IN” position.
CROSSOVER INPUTS (14)
These are the HI Z INPUTS for the ELECTRONIC CROSSOVER when installed. Two
parallel input jacks are again provided at this point, allowing the flexibility of line out capa¬
bility here as well. These jacks are also not chassis grounded and will provide a QUASI-
BALANCED input capability to minimize potential groundloops. Again, this feature is
automatic. As mentioned, the output of the low Z input circuitry of channel B is always
connected to these inputs, which allow the LOW Z INPUT to be used as the ELECTRONIC
CROSSOVER input if desired. These inputs then can be used as the FULL RANGE outputs
allowing additional patching capability.
CAUTION: When a full range signal is patched into either the XLR input or the crossover
inputs on channel B to feed the crossover module itself this full range signal is also routed to
the channel B input. The final patching from the crossover output to the channel B input
■ d i s c onnects this full range signal feed to the channel B input and instead is patched to the
appropriate crossed-over signal. This occurs because the channel B input jacks are switching
type. If you were to inadvertently disconnect the cable which is routing the crossed-over
signal to the channel B input, the switching arrangement will feed a full range signal to that

channel and could possibly destroy the transducer that is connected to this channel output.
ALWAYS REDUCE LEVELS BEFORE ATTEMPTING TO MAKE ANY PATCHING
CHANGES.
CROSSOVER MODULE RECEPTACLE (15)
This receptacle only receives a PL-MODULE ELECTRONIC CROSSOVER. The PL-
MODULES are optional accessories and are available in many different crossover frequen¬
cies. Some modules contain special equalization and special padding for a particular Peavey
speaker enclosure. Always be sure to select the correct module for your speaker system.
Other special purpose modules are also available for usage in this receptacle. As such this
receptacle supplies both the input and output patch facilities and the power supply "feeds" for
these active electronic devices.
CROSSOVER LOW OUTPUT (16)
This jack supplies the crossed-over low frequency output from the installed PL-MODULE
ELECTRONIC CROSSOVER. This output must be patched to the appropriate power amp
input jack to “create” an operational biamp system. On some special purpose modules, this
output jack is not used.
CROSSOVER HIGH OUTPUT (17)
This jack supplies the crossed-over high frequency output from the installed PL-MODULE
ELECTRONIC CROSSOVER. This output must also be patched to the appropriate power
amp input jack to create an operational biamp system.
SPEAKER OUTPUTS (18)
Same function and comments as channel A.
MODE SWITCH (19)
This switch is used to select either STEREO or BRIDGE mode of operation.
DDT SWITCH (20)
This switch is used to either ENABLE or DEFEAT the DDT compressor.
CIRCUIT BREAKER (21)
The CS-800X now uses a circuit breaker in place of the main fuse. This breaker is provided
to limit the current to the associated power transformer and thereby protect it from overheat¬
ing and possible destruction due to fault conditions in the amplifier. The trip current value
has been carefully chosen to allow continuous power output performance while still provid¬
ing adequate protection for the power transformer. Normally this breaker should not trip
unless there is a fault in the amplifier circuitry that draws excessive mains current. However,
abnormal conditions such as a short circuit on either or both channels or continuous operation
at overload or clipping, especially into 2 ohm, load will cause the breaker to trip. If this
occurs simply reset the breaker and correct the cause of the overload. When tripped, the
button on the breaker will be outward nearly 1/2", and can be reset by pushing inward. A
normal reset button length is about 1/4”. If this “thermal” type breaker does trip, then simply
pushing the button back in will reset it after waiting a brief period of time to allow it to cool
down. If the breaker trips instantly each time you attempt to reset it, then the unit should be
taken to a qualified service center for repair.

MAINS POWER SOURCE (120 V Products Only) (22)
The CS-800X is fitted with a single heavy duty #14 AWG 3 conductor line cord and a
conventional AC plug with a ground pin. It should be connected to an independent mains
circuit capable of supporting at least 15 AMPS continuously or greater. This is particularly
critical for sustained high power applications. If the socket used does not have a ground pin, a
suitable ground lift adaptor should be used and the third wire grounded properly. Never break
off the ground pin on the CS-800X. The use of extension cords should be avoided, but if
necessary, always use a three-wire type with at least a #14 AWG wire size. The use of
lighter wire will severely limit the power capability of this amplifier. Always use a qualified
electrician to install any necessary electrical equipment. To prevent the risk of shock or fire
hazard, always be sure that the amplifier is properly grounded.
INSTALLATION AND CONNECTION:
The Peavey CS-800X commercial series power amplifier is designed for durability in com¬
mercial installations and the quality of performance required in studio and home applications.
The unit is a standard rack-mount configuration, 5 1/4" high, and is cooled by an automatic
two-speed internal fan. All the input and output connections are on the back panel. The front
panel contains LED indicators for power and DDT activation, detented/calibrated sensitivity
controls, and a mains power switch.
INDUSTRIAL AND COMMERCIAL INSTALLATIONS
For commercial and other installations, where sustained high power operation is required, the
CS-800X should be mounted in a standard 19" rack. It is not necessary to leave rack space
between each amplifier in the stack, since the fan pulls air in from the rear and exhausts the
hot air out the front. An adequate “COOL” air supply must be provided for the amplifier
when rack-mounted. The internal fan must have a source of air that is not preheated by other
equipment. The amplifier will start up in “LOW SPEED” fan operation and will normally
stay at low speed operation unless sustained high power operating levels occur. Then, as the
amplifier “HEAT SINKS” heat up, the automatic thermal sensing circuitry will cause high
speed operation to occur. Depending upon signal conditions and amp loading, high speed fan
operation may continue, or it may cycle continuously between high and low. This situation is
quite normal. If cooling is inadequate due to preheated air, or a reduction of air flow^ occurs
due to blockage of the amplifier inlet/outlet ports, or if the amplifier is severely overloaded or
short circuited, then the amplifier thermal sensing system may cause temporary shutdown of
that particular channel. This is indicated by the channel power LED (on the front panel)
ceasing to illuminate. Depending upon available cooling air, operation should be restored in
that channel relatively quickly, and the power LED will be illuminated. In any event, correc¬
tive action should be taken to determine the cause of the thermal shutdown. If the amplifier
is not severely overloaded or shorted and air flow is normal in and out of the unit, steps
should be taken to provide a cooler environment for all the amplifiers. As a general rule, the
cooler electronic equipment is operated, the longer its useful service life.
STUDIO AND HOME INSTALLATION:
In most low to medium power applications, the CS-800X can be mounted in any configura¬
tion. It is desirable, if at all possible, that the unit be located at the top of an equipment stack.

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