Peavey CS 1200H User manual

CS®1200H Operations Manual
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power amplifier
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2
Intended to alert the user to the presence of uninsulated “dangerous voltage” within the product’s
enclosure that may be of sufficient magnitude to constitute a ris of electric shoc to persons.
Intended to alert the user of the presence of important operating and maintenance (servicing)
instructions in the literature accompanying the product.
CCAAUUTTIIOONN::Ris of electrical shoc — DO NOT OPEN!
CCAAUUTTIIOONN::To reduce the ris of electric shoc , do not remove cover. No user serviceable parts inside.
Refer servicing to qualified service personnel.
WWAARRNNIINNGG::To prevent electrical shoc or fire hazard, do not expose this appliance to rain or moisture.
Before using this appliance, read the operating guide for further warnings.
Este símbolo tiene el propósito, de alertar al usuario de la presencia de “(voltaje) peligroso” sin
aislamiento dentro de la caja del producto y que puede tener una magnitud suficiente como para
constituir riesgo de descarga eléctrica.
Este símbolo tiene el propósito de alertar al usario de la presencia de instruccones importantes sobre la
operación y mantenimiento en la información que viene con el producto.
PPRRCCAAUUCCIIOONN::Riesgo de descarga eléctrica ¡NO ABRIR!
PPRRCCAAUUCCIIOONN::Para disminuír el riesgo de descarga eléctrica, no abra la cubierta. No hay piezas útiles
dentro. Deje todo mantenimiento en manos del personal técnico cualificado.
AADDVVRRTTNNCCIIAA::Para evitar descargas eléctricas o peligro de incendio, no deje expuesto a la lluvia o
humedad este aparato Antes de usar este aparato, Iea más advertencias en la guía de operación.
Ce symbole est utilisé dans ce manuel pour indiquer à l’utilisateur la présence d’une tension dangereuse
pouvant être d’amplitude suffisante pour constituer un risque de choc électrique.
Ce symbole est utilisé dans ce manuel pour indiquer à l’utilisateur qu’il ou qu’elle trouvera d’importantes
instructions concernant l’utilisation et l’entretien de l’appareil dans le paragraphe signalé.
AATTTTNNTTIIOONN::Risques de choc électrique — NE PAS OUVRIR!
AATTTTNNTTIIOONN::Afin de réduire le risque de choc électrique, ne pas enlever le couvercle. Il ne se trouve à
l’intérieur aucune pièce pouvant être reparée par l’utilisateur. Confiez I’entretien et la réparation de
l’appareil à un réparateur Peavey agréé.
AAVVRRTTIISSSSMMNNTT: Afin de prévenir les risques de décharge électrique ou de feu, n’exposez pas cet
appareil à la pluie ou à l’humidité. Avant d’utiliser cet appareil, lisez attentivement les avertissements
supplémentaires de ce manuel.
Dieses Symbol soll den Anwender vor unisolierten gefährlichen Spannungen innerhalb des Gehäuses
warnen, die von Ausreichender Stär e sind, um einen ele trischen Schlag verursachen zu önnen.
Dieses Symbol soll den Benutzer auf wichtige Instru tionen in der Bedienungsanleitung aufmer sam
machen, die Handhabung und Wartung des Produ ts betreffen.
VVOORRSSIICCHHTT:: Risi o — Ele trischer Schlag! Nicht öffnen!
VVOORRSSIICCHHTT:: Um das Risi o eines ele trischen Schlages zu vermeiden, nicht die Abdec ung enfernen. Es
befinden sich eine Teile darin, die vom Anwender repariert werden önnten. Reparaturen nur von
qualifiziertem Fachpersonal durchführen lassen.
AACCHHTTUUNNGG::Um einen ele trischen Schlag oder Feuergefahr zu vermeiden, sollte dieses Gerät nicht dem
Regen oder Feuchtig eit ausgesetzt werden. Vor Inbetriebnahme unbedingt die Bedienungsanleitung lesen.
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3
IIMMPPOORRTTAANNTT SSAAFFEETTYY IINNSSTTRRUUCCTTIIOONNSS
WWAARRNNIINNGG::When using electrical products, basic cautions should always be followed, including the following:
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with a dry cloth.
7. Do not bloc any of the ventilation openings. Install in accordance with manufacturer’s instructions.
8. Do not install near any heat sources such as radiators, heat registers, stoves or other apparatus (including amplifiers)
that produce heat.
9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one
wider than the other. A grounding type plug has two blades and a third grounding plug. The wide blade or third prong is
provided for your safety. If the provided plug does not fit into your outlet, consult an electrician for replacement of the
obsolete outlet.
10. Protect the power cord from being wal ed on or pinched, particularly at plugs, convenience receptacles, and the point
they exit from the apparatus.
11. Note for UK only: If the colors of the wires in the mains lead of this unit do not correspond with the terminals in your
plug‚ proceed as follows:
a) The wire that is colored green and yellow must be connected to the terminal that is mar ed by the letter E‚ the earth
symbol‚ colored green or colored green and yellow.
b) The wire that is colored blue must be connected to the terminal that is mar ed with the letter N or the color blac .
c) The wire that is colored brown must be connected to the terminal that is mar ed with the letter L or the color red.
12. Only use attachments/accessories provided by the manufacturer.
13. Use only with a cart, stand, tripod, brac et, or table specified by the manufacturer, or sold with the apparatus. When a
cart is used, use caution when moving the cart/apparatus combination to avoid injury from tip-over.
14. Unplug this apparatus during lightning storms or when unused for long periods of time.
15. Refer all servicing to qualified service personnel. Servicing is required when the apparatus has been damaged in any
way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus,
the apparatus has been exposed to rain or moisture, does not operate normally, or has been dropped.
16. Never brea off the ground pin. Write for our free boo let “Shoc Hazard and Grounding.” Connect only to a power
supply of the type mar ed on the unit adjacent to the power supply cord.
17. If this product is to be mounted in an equipment rac , rear support should be provided.
18. Exposure to extremely high noise levels may cause a permanent hearing loss. Individuals vary considerably in suscep-
tibility to noise-induced hearing loss, but nearly everyone will lose some hearing if exposed to sufficiently intense noise
for a sufficient time. The U.S. Government’s Occupational Safety and Health Administration (OSHA) has specified the
following permissible noise level exposures:
Duration Per Day In Hours Sound Level dBA, Slow Response
890
692
495
397
2100
1
1
⁄ 2 102
1105
1
⁄ 2 110
1
⁄ 4 or less 115
According to OSHA, any exposure in excess of the above permissible limits could result in some hearing loss. Ear plugs or protectors to the
ear canals or over the ears must be worn when operating this amplification system in order to prevent a permanent hearing loss, if exposure
is in excess of the limits as set forth above. To ensure against potentially dangerous exposure to high sound pressure levels, it is
recommended that all persons exposed to equipment capable of producing high sound pressure levels such as this amplification system be
protected by hearing protectors while this unit is in operation.
SSAAVV TTHHSS IINNSSTTRRUUCCTTIIOONNSS!!
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4
CCSS®®11220000HH PPoowweerr AAmmpplliiffiieerr
Congratulations on your purchase of the CS 1200H power amplifier from Peavey—designed for years
of reliable, flawless operation under rigorous use. This amplifier offers the sonic superiority and
unsurpassed reliability for which Peavey is famous, while remaining surprisingly compact. Advanced
technology and extensive protection circuitry allow operation with greater efficiency into difficult
loads and power conditions. The DDDDTT™(Distortion Detection) circuit ensures trouble-free operation
into loads as low as 2 Ohms. The Distortion Detection circuits protect drivers and ensure that sonic
integrity is maintained, even in extreme overload conditions. Peavey’s hi-efficiency design uses
patented Turbo-V cooling and variable speed DC fan. This cooling topology maintains a lower overall
operating temperature, resulting in longer output transistor life.
Although the Peavey CS 1200H amplifier is quite simple to operate and is housed in ultra-strong steel
chassis, improper use can be dangerous. This amplifier is very high-powered and can put out high
voltages and sizable currents at frequencies up to 30 Hz. Always use safe operating techniques
when operating this amplifier.
FFOORR YYOOUURR SSAAFFEETTYY,, RREEAADD TTHHEE IIMMPPOORRTTAANNTT PPRREECCAAUUTTIIOONNSS SSEECCTTIIOONN,, AASS WWEELLLL AASS IINNPPUUTT,, OOUUTTPPUUTT,, AANNDD
PPOOWWEERR CCOONNNNEECCTTIIOONN SSEECCTTIIOONNSS..
··1199"" 22--ssppaaccee‚‚ rraacc--mmoouunnttaabbllee ddeessiiggnn
··ppaatteenntteedd TTuurrbboo--VV ccoooolleedd hheeaatt ssiinnss wwiitthh vvaarriiaabbllee ssppeeeedd DDCC ffaann
··uullttrraa--ssttrreennggtthh sstteeeell cchhaassssiiss
··RRaammppUUpp™™ssiiggnnaall ccoonnttrrooll
··sstteerreeoo oorr bbrriiddggeedd--mmoonnoo mmooddeess ooff ooppeerraattiioonn
··ffrroonntt ppaanneell AACC ppoowweerr sswwiittcchh//cciirrccuuiitt bbrreeaaeerr
··aammpp ffuunnccttiioonn sswwiittcchh ffoorr ffuullll--rraannggee ooppeerraattiioonn oorr ccrroossssoovveerr hhiigghh//llooww ffrreeqquueennccyy oouuttppuuttss
··ttwwoo iinnddeeppeennddeenntt‚‚ aaddjjuussttaabbllee ccrroossssoovveerrss
··ttwwoo iinnddeeppeennddeenntt‚‚ llooww ffrreeqquueennccyy ffiilltteerrss
··ffiivvee ffrroonntt ppaanneell LLEEDD iinnddiiccaattoorrss ppeerr cchhaannnneell:: AACCTTIIVVEE,, DDDDTT™™,, SSIIGGNNAALL‚‚ TTEEMMPP aanndd DDCC
UUnnppaacckkiinngg
Upon unpac ing, inspect the amplifier. If you find any damage, notify your supplier immediately. Only
the consignee may institute a claim with the carrier for damage incurred during shipping. Be sure to
save the carton and all pac ing materials. Should you ever need to ship the unit bac to Peavey
Electronics, one of its offices, service centers, or the supplier, use only the original factory pac ing. If
the shipping carton is unavailable, contact Peavey to obtain a replacement.
MMoouunnttiinngg
The CS 1200H amplifier will mount in standard 19-inch rac s. Rear mounting ears are also provided for
additional support, which is recommended in non-permanent installations li e mobile or touring
sound systems. Because of the cables and connectors on the rear panel, a right angle or offset
screwdriver or hex ey will ma e it easier to fasten the rear mounting ears to the rails.
CCoooolliinngg RReeqquuiirreemmeennttss
The CS 1200H amplifier uses a forced-air cooling system to maintain a low, even operating
temperature. Air is drawn into the amplifier by fans on the front panel, courses through the cooling
fins of the tunnel-configured channel heat sin s, and then exhausts through the rear panel slots. If
either heat sin gets too hot, its sensing circuit will open the output relay, disconnecting the load
from that particular channel. It is important to have an exhaust outlet at the bac of the amplifier and
enough space around the sides of the amplifier to allow the cooling air to escape. If the amp is rac
mounted, do not use doors or covers on the front of the rac ; the inta e air must flow without
resistance. If you are using rac s with closed bac s, ma e sure that there is one (1) standard rac
space opening for every three mounted power amplifiers.
EENNGGLLIISSHH
FFeeaattuurreess
DDeessccrriippttiioonn
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5
OOppeerraattiinngg PPrreeccaauuttiioonnss
Ma e sure the mains voltage is correct and is the same as that printed on the rear of the amplifier.
Damage caused by connecting the amplifier to improper AC voltage is not covered by any warranty. See
the Connecting Power section for more information on voltage requirements.
NNoottee:: AAllwwaayyss ttuurrnn ooffff aanndd ddiissccoonnnneecctt tthhee aammpplliiffiieerr ffrroomm mmaaiinnss vvoollttaaggee bbeeffoorree mmaakkiinngg
aauuddiioo ccoonnnneeccttiioonnss.. AAllssoo,, aass aann eexxttrraa pprreeccaauuttiioonn,, hhaavvee tthhee aatttteennuuaattoorrss ttuurrnneedd ddoowwnn
dduurriinngg ppoowweerr--uupp..
Although the CS 1200H amplifier has RRaammppUUpp™circuitry, which raises the signal level gradually after the
output relay closes, it is always a good idea to have the gain controls turned down during power-up to
prevent spea er damage if there is a high signal level at the inputs. Whether you buy or ma e them, use
good-quality connections, input cables and spea er cables, along with good soldering technique, to
ensure trouble-free operation. Most intermittent problems are caused by faulty cables.
Consult the Wire Gauge Chart (below) to determine proper gauges for different load impedances and
cable lengths. Remember that cable resistance robs amplifier power in two ways: power lost directly to
resistance (I2R loss), and by lowering the total load impedance. Also ma e sure the mode switch is
correctly set for the desired application. See Sections on SStteerreeooand BBrriiddggeedd MMoonnoooperation for more
information.
WIRE GAUGE CHART
Cable Length
(In Feet)
Stranded Wire Gauge
(AWG)
Power Loss into
8 Ohms (%)
Power Loss into
4 Ohms (%)
Power Loss into
2 Ohms (%)
5 18 .79 1.58 3.16
16 .50 1.00 2.00
14 .31 .62 1.24
12 .20 .40 .80
10 .125 .25 .50
10 18 1.58 3.16 6.32
16 1.00 2.00 4.00
14 .62 1.25 2.50
12 .40 .80 1.60
10 .25 .50 1.00
40 18 8.00 12.60 25.20
. 16 4.00 8.00 1.60
14 2.50 5.00 10.00
12 1.60 3.20 6.40
10 1.00 2.00 4.00
8 .625 1.25 2.50
80 16 8.00 16.00 32.00
14 5.00 10.00 20.00
12 3.20 6.40 12.80
10 2.00 4.00 8.00
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CCoonnnneeccttiinngg IInnppuuttss
Input connections are made via the 3-pin XLR (pin 2+) or 6.3 mm plug “Combi” connectors on the
rear panel of the amplifier. The inputs are actively balanced. Pinout and polarity of connection
cables should be configured correctly (refer to the rear panel of the unit). The input overload
point is high enough to accept the maximum output level of virtually any signal source.
CCoonnnneeccttiinngg OOuuttppuuttss
All models have two output (spea er) connections per channel. Cables can be connected with
banana plugs, spade lugs, or bare wire to the 5-way binding posts. The preferred connection
method is via the Spea on connectors. Pin connections are noted on the rear panel of the unit.
CCoonnnneeccttiinngg PPoowweerr
The CS 1200H power requirements are rated at 1/8 power (typical music conditions). The
maximum power current draw rating is limited only by the front panel circuit brea er. Consult the
specifications in this manual for figures on the current that this amplifier will demand. Ma e sure
the mains voltage is correct and is the same as that printed on the rear of the amplifier. Damage
caused by connecting the amplifier to improper AC voltage is not covered by any warranty. Unless
otherwise specified when ordered, Peavey amplifiers shipped to customers are configured as
follows:
North America: 120 VAC/60 Hz
Europe, Asia, Australia: 230/240 VAC/50 Hz
South America: 120 VAC/60 Hz or 240 VAC/50 Hz
SStteerreeoo
For stereo (dual channel) operation, turn the amplifier off and set the mode select switch to the
stereo position. In this mode, both channels operate independently of each other, with their
input attenuators controlling their respective levels. Thus, a signal at Channel A’s input produces
an amplified signal at Channel A’s output, while a signal at Channel B’s input produces an
amplified signal at Channel B’s output.
BBrriiddggeedd MMoonnoo
Both amplifier channels can be bridged together to ma e a very powerful single-channel
monaural amplifier. Use extreme caution when operating in the bridged mode; high voltage may
be present at the output terminals. To bridge the amplifier, set the rear panel mode select switch
to the bridge position. Apply the signal to Channel A’s input (all Channel B’s input functions are
defeated) and connect the spea ers across the hot outputs (the “+” binding posts of Channels A
and B) or between the 1+ and 2+ pins of the Channel A Spea on®connector. The input level
control for channel A will be the master control for input level, the level control for the B channel
is inoperative. The active LED for the B channel will not light, which ma es it easy to identify
when the amp is in Bridge mode.
Unli e stereo mode, in which one side of each output is at ground, in the bridged mode both
sides are hot. If an output patch panel is used, all connections must be isolated from each other
and from the panel. The recommended minimum nominal load impedance in the bridged mode is
4 Ohms (equivalent to driving both channels at 2 Ohms). Driving bridged loads of less than 4
Ohms can activate the Load Fault Correction (LFC) circuitry resulting in a limiting of power, and
may also cause a thermal overload.
OOppeerraattiioonn MMooddeess
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AACC PPoowweerr SSwwiittcchh//CCiirrccuuiitt BBrreeaakkeerr ((11))
The CS 1200H amplifier has a combination AC switch/circuit brea er on the front panel. If the switch
shuts off during normal use, push it bac to the ON position once. If it will not stay on, the amplifier
needs servicing.
IInnppuutt AAtttteennuuaattoorrss ((22))
Whenever possible, set the attenuators fully cloc wise to maintain optimum system headroom. The
input attenuator controls (one for channel A, one for channel B) located at the front panel adjust gain
for their respective amplifier channels in all modes. See the specifications at the end of this manual
for standard voltage gain and input sensitivity information.
When operating in the bridged mode, the channel A attenuator controls the signal. See the section on
BBrriiddggeedd MMoonnooOperation for more information and precautions.
FFrroonntt PPaanneell IInnddiiccaattoorrss
The CS 1200H features four front panel discrete LED indicators per channel: AACCTTIIVVEE, DDDDTT, TTEEMMPP
and DDCC. These LED indicators inform the user of each channel’s operating status and warn of
possible abnormal conditions. This amplifier also features two 10-segment bar graph indicators
per channel: SSIIGGNNAALL.
SSiiggnnaall LLDD ((33))
This LED is at the bottom of the bar graph display and lights when its channel produces an output
signal of greater than 2 Volts RMS or 50 mV input with a 0 dB attenuation of the front panel nobs. It
is useful in determining whether a signal is reaching and being amplified by the amplifier. The 10-
segment graphs indicate the level of signal present.
DDCC LLDD ((44))
The DC LED lights to indicate that the channel’s output relay is open, disconnecting the spea er(s)
when the amplifier senses a DC voltage or subsonic high level signal at its output.
TTeemmpp LLDD ((55))
The Temp LED lights to indicate that the channel’s output relay is open, disconnecting the spea er(s)
due to an overheating condition. Once the channel temperature has returned to safe operating
conditions the LED will turn off and the spea er(s) will be reconnected.
DDDDTT AAccttiivvee LLDD ((66))
Illuminates when DDT Compression is ta ing place. With the Enable/Defeat switch in the Defeat
position, the LED indicates when clipping distortion is occuring.
-10
ACTIVE
DDT
TEMP
DC
SIGNAL
dB
-80
-30
-15
-3
-1
0dB
-6
-80
-30
-15
-10 -3
-1
0dB
-6
POWER ON
DESIGNED AND MADE IN U.S.A.
1200 WATT PROFESSIONAL STEREO POWER AMPLIFIER
-15
-13
-9
+3
dB
-20
-7
-5
-3
0
2
1 8
FFrroonntt PPaanneell
4 5 6 73
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8
AAiirr xxhhaauusstt VVeennttss ((99))
These vents provide an exhaust path for the hot air from the heatsin s. Any restriction or bloc age
could cause excessive opertion temperature and the unit could shut down.
MMooddee SSeelleecctt SSwwiittcchh ((1100))
The rear panel MODE Select Switch determines whether the amplifier is in stereo or bridged mono
mode.
DDDDTT SSwwiittcchh ((1111))
This switch is used to either Enable or Defeat the DDT compressor. It is recommended to leave the
DDT compression enabled at all times to protect your spea ers from damage square waves.
CChhaannnneell IInnppuutt ((1122))
This input features a combo connector that will accept a standard three-pin male XLR, 1/4"
(6.3 mm) TRS (Tip-Ring-Sleeve), or 1/4" (6.3 mm) mono plug. An electronically balanced input is
available via XLR and 1/4" TRS use. The unit is internally wired for the following:
Input XLRTRS
(+) Pin 2 Tip
(-) Pin 3 Ring
GND Pin 1 Sleeve
RReeaarr PPaanneell
12 10 11
AAccttiivvee LLDD ((77))
The ACTIVE LED indicates that its channel’s output relay is closed and the channel is operational.
In Bridge Mode, the Channel B LED goes off.
AAiirr IInnttaakkee VVeenntt ((88))
Cool air enters the amplifier here and exhausts through the rear vents. Any restriction or bloc age
could cause excessive operation temperatures and the unit could shut down.
17 18 19 19 2120
17 18
9
13
14
15
16
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9
CCrroossssoovveerr AAddjjuussttmmeenntt KKnnoobb ((1133))
The CS 1200H is equipped with two independent‚ two-way crossovers adjustable from 40 Hz to 300 Hz.
These crossover frequencies are appropriate for use with a subwoofer system. The output of these
crossovers is selected by the Amp Function switch and connected to the corresponding amplifier
channel. Frequencies above the nob setting will be connected to the corresponding channel when the
Amp Function switch is in the HIGH PASS position. Frequencies below the nob setting will be
connected to the corresponding channel when the Amp Function switch is in the LOW PASS position.
The FULL RANGE position bypasses the crossover.
AAmmpp FFuunnccttiioonn SSwwiittcchh ((1144))
The rear panel Amp Function Select Switch determines whether the associated channel is connected for
full range operation or to the crossover high frequency or low frequency outputs.
LLooww CCuutt SSwwiittcchh ((1155))
The LOW CUT switch is a recessed push switch used to defeat or engage the LOW CUT filter. Pushing the
switch to the in position will engage the filter.
LLooww CCuutt AAddjjuussttmmeenntt KKnnoobb ((1166))
The CS 1200H is equipped with two independent low frequency filters. These filters are adjustable from
20 Hz to 100 Hz and are designed to reduce frequencies below those capable of being produced by the
loudspea ers, or to reduce room “rumble.” Frequencies below the nob setting of the corresponding
channel will be attenuated.
HHiigghh PPaassss//FFuullll RRaannggee OOuuttppuutt CCoonnnneeccttoorr ((1177))
The HIGH PASS/FULL RANGE OUTPUT connector function is dependent on the setting of the
corresponding Amp Function switch. This connector allows patching the frequencies above the
crossover nob setting to a secondary amplifier. If the Amp Function switch is in the HIGH PASS
position, the high frequency portion of the crossover will be present at the connector. If the Amp
Function switch is in the FULL RANGE or LOW PASS position, the crossover will be bypassed and allow
patching the full range signal to a secondary amplifier.
LLooww PPaassss OOuuttppuutt CCoonnnneeccttoorr ((1188))
The LOW PASS OUTPUT connector allows patching the frequencies below the crossover nob setting to
a secondary amplifier. This output remains at low frequencies independent of the Amp Function switch
setting.
SSppeeaakkoonn®®OOuuttppuutt CCoonnnneeccttoorr ((1199))
Each channel features a four-wire Spea on connector for the output. In both channels, the 1+ pin is the
channel signal output and the 1- pin is chassis ground. On the Channel A connector, the 2+ pin carries
the Channel B signal output and the 2- pin is chassis ground.
BBiinnddiinngg PPoosstt OOuuttppuutt CCoonnnneeccttoorrss ((2200))
Each channel features a pair of shoc -proof binding posts connected in parallel with the Spea on
connector. The red binding posts are the signal output from each channel, and the blac binding posts
are chassis ground. For Bridge mode operation, only the red binding posts are used. The Channel A red
binding post should be considered the positive output for the system and should be connected to the
positive input of the associated loudspea er system.
AACC LLiinnee CCoorrdd CCoonnnneeccttoorr ((2211))
Provided to accept the removable (IEC) type AC line cord. Connect only to proper source (see bac panel
mar ings).
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10
The CS 1200H incorporates several circuits to protect both itself and loudspea ers under virtually any
situation. Peavey has attempted to ma e the amplifier as foolproof as possible by ma ing it immune
to short and open circuits, mismatched loads, DC voltage, and overheating. If a channel goes into the
Distortion Detection or DDT gain reduction mode, the spea er load remains connected, but clipping
percentage or output power are instantly reduced. When a problem occurs that causes a channel to go
into a protection mode, the TEMP LED or DC LED for that channel will glow. DC voltage on the output,
excessive subsonic frequencies, or thermal overload will cause the channel’s output relay to
disconnect the spea er load until the problem is corrected or the amplifier cools down.
DDDDTT
Peavey’s DDT compression system allows maximum performance of the amplifier/spea er
combination by preventing the power amp from running out of headrooom (clipping). This
compression system is activated by a unique circuit that senses signal conditions that might overload
the amplifier and reduce the amplifier’s gain when clipping is imminent. The threshold of compression
is clipping itself and no specific threshold control is used. This technique effectively utilizes every watt
available for the power amplifier to reproduce the signal while at the same time minimizes clipping
and distortion, and thus significantly reduces the potential of loudspea er degradation and damage.
LLFFCC IImmppeeddaannccee SSeennssiinngg
The CS 1200H features innovative circuitry that allows safe operation into any load. When an amplifier
sees a load that overstresses the output stage, the Load Fault Correction circuit adjusts the channel
gain to a safe level. This method of output stage protection is far superior to conventional, brute force
type limiting found on other amplifiers. The LFC circuit is sonically transparent in normal use and
unobtrusive when activated.
TThheerrmmaall PPrrootteeccttiioonn
The internal fan will eep the amplifier operating well within its intended temperature range under all
normal conditions. If a channel’s heat sin temperature reaches sufficient temperature which may
indicate an obstructed air supply, that channel will independently protect itself by disconnecting its
load and shutting down until it has cooled. During this time, the channel’s TEMP LED will light. During
this time, the ACTIVE LED will go out, the Temp and DDT LEDs will stay lit and the cooling fan will stay
running at high speed.
SShhoorrtt CCiirrccuuiitt
If an output is shorted, the LFC circuit will automatically protect the amplifier. The LFC circuit senses
the short circuit as an exteremly stressful load condition and mutes the signal, protecting the
channel’s output transistors from over current stress. Approximately 1.5 seconds later, the RampUp
circuit will attempt to return the amplifier to normal operation. If the short is still present, the LFC
circuit will again mute the signal. This cycle of operation will continue until the short is removed from
the output.
DDCC VVoollttaaggee PPrrootteeccttiioonn
If an amplifier channel detects DC voltage or subsonic frequencies at its output terminals, its output
relay will immediately open to prevent loudspea er damage. The channel’s DC LED will light.
TTuurrnn--OOnn//TTuurrnn--OOffff PPrrootteeccttiioonn
At power-up, the amplifier stays in the protect mode, with outputs disconnected, for approximately
two seconds while the power supplies charge and stabilize. When power is removed, the spea er
loads immediately disconnect so that no thumps or pops are heard.
PPrrootteeccttiioonn FFeeaattuurreess
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