Peavey CS-900 User Manual

Oulpul Conntetions
Two typesof output conneclors are provided ontherearpanelof the amplifjer.Twostandard '//‘phonejacks wired in paraiiel (17) and one
set of 6-way binding posts (18) are available from each channel. Due to the high currents at full output it is recommended th0t#f16 AWG or
larger wire size be used whenever possible. ForeXtremely long runs (30' or greater). tf14AWGshould be used. Smallerwnre sizes will v^aste
powerand yield less than optimum results at the speaker It is suggested that in commercial and other non-portableapplicalions, the 5-way
binding posts (18) be used instead oftheVV'phone jacks Thebinding posts are industry standard and mating banana plugs are available at
most electronic distributors. As with any electronic equipment, proper phase of the outputs is a necessity. A little time spent correctly
identifying the wiring can save a lot of problems in the field. The CS-900 bias a continuous rating oUSO watts RMS jnto4 ohms. Music power
operation into 2 ohms should be considered normal and generally will not present any problems. However, continuous operation under
theseconditionsmightcause thermal shutdown, depending upon cooling air temperature. Operating intcloadsbelow2ohms, although safe
because of electronic protection mechanisms, should be avoided.
OPERATION
The CS-900 commercial series power amplifier is designed for maximum ease and flexibility of operation. When the unit is installed and
connected as described in the previous sections, operation is as simple as turning on the mains switch (5) and turning up the sensitivity
controls (i) to full clockwise setting, and then adjusting the associated mixer or preampiification equipment to supply the necessary signal
levels to provide the desired output level or until the front panel DDT active LED indicator shows that the amplifier is compressing. Further
increases m signal levels beyond this point will not prcwuce any significant Increase In output and could cause distortion problems,
FRONT PANEL
IN«JTSENSITIVITY CONTROLS (1)
The C$-900 employs a31 deten ted, calibrated sensitivity control foreach channel. These controlsare labeled in amorefuncUonsi manner,
replacingtheconventionalOto 10 segmented circle wH:h the actual input sensitivity^atings of theamplifierforvarious settings of this control
In the peat this control has often confused even the most experienced audio technician as to Its purpose and usage, especially when It is
simply called level (rather than sensitivity). This new labeling/calibrating technique will help to explain the need and function of these
controls and the significance of the sensitivity rating. We offer the following In way of explanation: The input sensitivity rating of a power
amplifier Is the RMS voltage level required at the input to produce full rated power into the rated load atthe output. Thisvoltagethen becomes
the levef at which the associated mixer must operate In order to drive the amplifier to full output. Operation al levels above this rating will
causethe power ampliflertoclip (producedlstortlonj unless the associated amplifier hasacompressororllmitertomlnlmize thisdistoftion.
Such a system, called DDT'" (U.S. Patent #4,318,053), Is Included In CS-900 power amplifiers, and the advantages should be obvious.
Without DDT, the sound engineer must 'Tide gain" on the mixer or employ outboard compressor/limlter, In order to prevent power amp
clipping.
Traditionally, the input sensitivity rating of a power ampIMier receives low billing on a ^picet specification sheet. Often It gets lost among
other Interesting specs, such as damping factor, slew rate, transient intermodulation distortion and others. This rating, however, must be
known to have performance visibility atthe mixer Further, the rated sensitivity on thespecsheetisonly correct when the power amplifier
sensitivity control is setat full clockwise or maximum setting Any other setting increasesthevalue. With a numbered circlefrom OtolO, this
new higher value Is not indicated. Thus, the CS-900 sensitivity control Iscallbraled in both RMS voltage levels (usually given In power amp
spec sheets) and the equi valent dBV values (usually listed intyplcai mixer specs). The OBV values are more useful, si nee most contemporary
mixers employ LED arrays to indicate mixeroutput levels and arecalibrated In dBV. Knowing the poweramplifrer sensitivity rating indBV will
allow the mixeroperatorto know the status of the power amplifier (whether they are clipping/compressing or not) by noting which LED on
the mixer is peaking. Obviously, the LEO labeled the same or closest to the sensitivity rating of the power amplifier will Indicate full power
output ofthesystem. Operation below that level will indicate how much so called poweramplifierheadroornls left. Operation above that level
win cause clipping (or compression iftheDOT system is operational). Perhaps an exarnplewill be helpful: Referring to the CS-900 face plate,
you will notice that at full clockwise setting of The sensitivity control, the sensitivity rating is 1.4V RMS or +3 dBV. The critical LED on the
driving mixerlhen IS the one labeled+3 dBV It will correlate with the CS-900 DDT active LED in that wheneverthe+SdBV LED onthe mixer
flasheson peaks, the DOT active LED will aisofiash indicating full power output is achieved. If the CS-900 sensitivity control was adjusted to a
higher value, this new value would become the new correlation level on the associated mixer. There Isa very simple rule regarding the setting
of the sensitivity jor level) control:
‘‘Unless there Is a specific reason not to* the sensitivity control on any power amplifier should be set to full clockwise
position, resulting in the minimum sereltivlty rating/
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Peavey CS-900 Specifications

General

Brand	Peavey
Model	CS-900
Category	Amplifier
Language	English