Peavey 900 Mixer Music Mixer User Manual

Peavey 900 Mixer Music Mixer User Manual
9200 MIXER
To prevent electrical shock or fire
hazard, do not expose this
appliance to rain or moisture.
INPUT CIRCUITRY - In order for a mixer to be
compatible in most applications, it must have the
capability to control the sensitivity of the input circuitry
of each channel. This requires an ATTENUATOR (1),
sometimes called a pad. Some mics and signal sources
can be at such a level as to overdrive or clip the input
circuitry of a mixer. An input attenuator allows the
operator to reduce the input gain when input clipping
occurs. Some manufacturers put attenuators in their
snake or stage box to be able to control the sensitivity of
the mic or signal source. This is not the best approach if
you are sending your signals through cable runs of any
length. The more signal being carried by the mic cable
the less susceptible is the signal to picking up hum or
noise which allows for an improved signal-to-noise
ratio. Many times it would be impossible to make an ad-
justment on one of the attenuators if necessary during
the performance. You shouldn't have to run up to the
stage and pick up the drummer's leg so you can adjust
a mic input!
In use, the operator must adjust the input
attenuator in such a manner that input clipping is avoid-
ed. This can easily be done by setting up the channel
with the highest expected input signal level and ad-
justing the input attenuator so that no clipping or digtor-
tion is heard from the speaker system. After the mixer
has been used several times, the operator will have a
very good idea of the signal levels encountered and will
be able to set up the attenuators accordingly. The
different types of microphones will have different output
levels and different performers will get widely varying
levels from mics depending on the strength of their
voices and/or their basic "mic techniques”.
The input attenuator should be operated in the
position yeilding the least attenuation required to avoid
clipping. Operation in this mode allows maximum gain
to be utilized in the input preamp where it is most ef-
ficiently obtained. Excessive input padding sometimes
makes necessary higher settings of the channel gain
controls and/or master control thus yeilding a less than
optimum signal-to-noise ratio for any given situation.
It is important to realize that not all “breakup” 1$
caused by the mic signal overloading the input stage of
the mixer. If the performers mic technique includes
very close and/or very loud situations, the internal
elements of the mic can “bottom out” or distort just as a
loudspeaker can when it is overdriven. Quite a few of
the mics now used by performers lack the dynamic
range required to adequately handle the tremendous
sound pressure levels encountered in a very loud rock
and roll concert situation. It is vital for the professional
soundman and the musicians to be aware of the
limitations of the various links in the audio system in
order to correctly diagnose and solve the various
problems encountered in a sound reinforcement situa-
Overall, the input attenuator is the first control in
the circuit and must be set up properly in order for the
remaining circuits to function properly. “Common
sense" and experience operating the 900 Mixer on
several jobs will allow the operator to achieve superb
results in virtually any mixing situation. Qur variable in-
put attenuator allows for much more flexibility than
some other manufacturer's mixers that only have
switchable fixed attenuation of maybe 10 to 20 dB,
where sometimes 10 dB may not be enough and 20 dB
may be too much attenuation. The 900 Mixers input
attenuator is continuously variable from 0 dB to -40 dB.
—15 15 +
channel mixing element for determining the all-
important monitor mix. The signal for the monitor send
is obtained right after the input preamp and before the
channel EQ. This is referred to as a Monitor Pre-send
Control, i.e,, it is before or pre to the channel equaliza-
tion and slider level control. This makes It independent
of these controls, meaning that any changes made 10
the EQ or channel level will not affect the monitor
system. Having the monitor send with the pre capability
is absolutely VITAL to avoid feedback of the monitor
system when EQ and normal incremental outpul
variations are made in the channel fader during the
course of the performance.
EQUALIZATION - The equalization circuitry of the
900 Mixer is the latest active type utilizing negative feed-
back technology. We selected circuitry that produces a
"shelving" type of action because the conventional type
circuitry used by some manufacturers tends to create
erratic, or sometimes harsh sounding results when in
the near-maximum boost positions. These two
equalization controls will produce extremely smooth ac-
tion as well as giving effective tone control. Experience
will show their utility in achieving professional channel
equalizaiton on the job.
It should be remembered that these active
equalization circuits are a form of "electronic crossover”
in which the equalizaiton controls are similar to level
controls for their respective frequency bands.
Generally, it is poor operating practice to use both
equalizer controls in the deep cut (counter-clockwise)
positions since this results in substantially lower gain
from the channel. It should be remembered that the
balance of highs and lows is a relative situation, cutting
overall channel gain should properly be done by the
output slide attenuator or input attenuator.
capable of better than 15 dB boost or cut @ 100 Hz with
a sloping characteristic exhibited up to the crossover
point. The shelving action of this control has proven to
yeild a much more satisfying and effective equalization
characteristic than some of the "wide open” equaliza-
tion circuits claiming 20-25 dB boost and cut. The ac-
tion of this equalizaiton control is conventional and
should present no problem in operation. Boost is ob-
tained in the righthand (clockwise) postion while cut is
obtained in the lefthand (counter-clockwise) position.
The vertical (12 o'clock) position yields a flat (no boost
or cut) response and is the position from which all tonal
balancing should be started.
capable of 15 dB boost or cut @ 5 kHz with a shelving
characteristic sloping down to the crossover point. The
boost or cut action of this control is very similar to that of
the low equalizer with the exception of its high frequen-
cy effect. Boost is obtained to the right of the center
position. Flat response is obtained in the center (12
o'clock) position.
Caution should be exercised in using extreme low-
frequency boost to avoid emphasing objectionable
wind noises or rumble from the microphone as well as
any hum that might enter the mixer from external
sources. Excessive treble boost should be avoided to
keep residual noise from the amplification circuitry to a
reasonable level as well as to avoid a strident or
screeching tonality in the output program material.
In sound reinforcement, there is nothing holy
about an entirely flat equalization setting. If it is
necessary to use moderate amounts of equalization,
then you should be willing to do so, considering that the
“ideal” flat settings are almost never used, even in the
recording studio, and even less often in most sound
reinforcement applications.
The EFFECTS SEND CONTROL (5) is the channel
level for determining the amount of signal from each
respective channel to be sent to the effects output or to
be mixed into the reverb summing buss. The effects
send circuit has been designed to provide multiple
functions which will be explained further in the master
control section.
output level control that determines the mix into the
main summing buss. lis calibration is in decibels of
attenuation and this is why the numbering sequences
goes from off (infinity = oo), or maximum attenuation to
zero (0), or no attenuation. Remember that attenuation
is the cutting or reduction of the signal level i.e., the
more attenuation, the more you have cut down the
signal level. The output fader is calibrated in accor-
dance with standard practice for professional audio
Proper setting of the input attenuator (pad) should
produce adequate gain within the input preamp to allow
slider settings approximately in the center (ap-
proximately -20 dB). You should also remember that
the input attenuator is a kind of pre gain control and its
settings will most definitely influence the settings for the
output slider with any given input signal. The input
attenuator should be adjusted for the maximum gain
that will allow distortion free performance, then the out-
put slider level should be adjusted for proper mix.
It is very poor operating practice to use the input
pads in the extreme cut positions and then have to set
the output sliders in their close to maximum positions to
obtain adequate channel output. This type of operation
results in less than optimum signal-to-noise ratios as
well as contributing to headroom problems. As with any
system, “common sense” must be combined wifi
operating knowledge to produce salisfactory results.
Overall, the channel controls should be set to provide a
reasonable amount of “adjustment” Le., none of the
gain controlling elements (input attenuator/output
slider) should be operated near their extreme up or
down positions. After several hours usage, the operator
will have acquired a good “feel” for the characteristics
of the controls and should be able to suitably handle
any mixdown situation encountered in the field with
satisfactory results.
MASTER AREA - The master area of the 300 Mix-
er contains all the master or final output controls for the
mixing busses. The main mixing buss egualization
features shelving type high (9), and low (10) EQ. The
Effects level (12) is the master control for the effects
mixing buss.
The master level controls (7) (14) of the 900 Mixer
should be setin such a manner that they are close to the
center of their travel to take advantage of maximum
control action. It is poor practice to run the channel
faders up near maximum and then run the main faders
near the low end to achieve the desired output levels.
Operation in this manner will cause the operator to lose
his "range" in control action with all the gain located in
one element while the other is near its stop position.
Best practice calls for most controls to be operated in
the middle of their operating range to allow maximum
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mixing control margins (travel). Remember, that while
mixing, It is important to allow yourself adequate
margins within which to operate and by using any of the
faders in their extreme (close to the stop) positions, you
have effectively reduced your range of control. This
manner of operation also tends to create “headroom”
These master controls allow the operator complete
flexibility for functions and should allow almost any mix-
ing situation to be handled by the S00. As with any
reasonably complex system, experience and operator
knowledge of the equipment are essential for satistac-
tory performance. The mixer, like the musician's instru-
ment, should be practiced on and learned. To properly
operate a mixer during a performance requires
thorough knowledge and trained reflexes to allow
proper responses under the stress of demanding and
sometimes sudden situations. The musician should
know his mixer almost as well as he knows his instru-
ment, so that his reactions will be both smooth and
proper to correct whatever problem or requirement that
should arise during a performance...a professional
must work at it!
The MASTER OUTPUT FADER (7) is the control
that determines the main output level for the output con-
nectors located on the rear panel. The main summing
amp, as well as the other two summing busses, are of
the very latest "zero null" type using negative feedback
to achieve maximum dynamic range, lowest noise, and
crosstalk, The master fader should be operated in ac-
cord with the proper operating practices as outlined
above. Experimentation and experience on several jobs
will allow the operator to achieve a "feel" for the right
settings for his requirements.
(10) is capable of 15 dB boost or cut @ 50 Hz. This
equalizer is similar to those used in the individual
channels and is designed to exhibit a “Shelving”
characteristic which has proven to yield the best results
in this type application. The controls are “flat” with no
boost or cut in the straight up (12 o'clock) position with
boost being obtained in the righthand (clockwise) posi-
tion. Care should be taken NOT to over-boost with the
master EQ controls, Since each channel is equiped with
equalization, it is poor practice to use too much ad-
ditional boost in this master section. Over-boosting on
low frequencies will impart a boomy and muffied tonall-
ty to the program material and will substantially
decrease the intelligibility of voices being mixed through
the console.
(9) is capable ot 15 dB boost or cut @ 10 kHz and is
designed to exhibit a “shelving” characteristic. The
operation of this EQ control is similar to the low EQ with
the exception of the fact that it controls the high ire-
quency portion of the audio spectrum. Care should be
taken not to over-boost the high frequencies to avoid
undue amplification of residual system noise (hiss) as
well as creating a “strident” or screechy sounding
system, High frequency over-boost also tends to create
undue acoustic feedback. When balancing ANY of the
equalizers for proper tonality, you always start with ALL
equalizers in their flat (12 o'clock) positions and work
from there. After you have spent several hours working
with any particular setup of mics, performers, etc, you
will acquire a good working equalization setup and De
able to achieve the desired tonality.
The important thing to keep in mind about the
equalization on the S00 Mixer is that each channel is
provided with its own set of EQ controls to correct
problems in that particular channel, while Master EQ is
provided to allow for overall tonal balance and feedback
control. We have not included this equalization system
to allow tremendous boost or cut but rather to allow in-
cremental EQ where it is needed. You must use com-
mon sense in the use of these controls in order to
achieve satisfactory tonal balance and intelligibility.
The EFFECTS LEVEL (12) is the control that deter-
mines the overall signal output level for the effects send
buss. This effects buss has two output connectors
associated with it, one is a high level output that can be
used to drive a power amplifier for an additional monitor
system and the other is a low level outpul designed to
drive the input of an effects device such as an echo unit,
phasor, digital delay line, etc. In addition to driving the
high and low level effects outputs, the effects level con-
trol also determines the drive to the internal reverb delay
line. This effects level control must be adjusted so that
the output level from the jack on the rear panel does not
overload the input circuitry of the effects unit you are
driving, thus causing clipping or other forms of distor-
tion. This is especially critical on some of the special
effects units that are designed to work with guitars or
other instruments with relatively low output levels.
The REVERS RETURN (13) is the gain control ele-
ment for the reverb system. The signal coming from the
reverb delay lines is amplified and the gain or amount of
signal sent to the main summing buss is controlled by
the reverb return.
The REVERB CONTOUR (11) is the control used
to vary the tonality of the reverb signal and 15 a low cut
type equalizer. This contour control is very useful in
tailoring the reverb sound and in controlling reverb in-
duced feedback. Balancing these reverb controls will
yield many combinations of reverb delay, tonality, and
The EFFECTS RETURN LEVEL (15) control is
provided for varying the input levels mixed into the main
mixing buss from the effects return input jack provided
on the rear panel. The effects return input jack allows
signals from mics or effects units to be patched directly
into the main mixing buss. This control may be con-
sidered a separate channel whose output is blended
into the main mix just as the individual channeis are.
The MONITOR MASTER FADER (14) is the output
level control for the main monitor system. The same
operating practices should be observed when using this
control as when using the main channel controls. The
individual channel monitor send controls should be set
in such a manner that will allow the monitor master
slider (fader) to be operated somewhere in the middie
of its travel to allow yourself adequate control margins,
up or down, as might be required on the job. The
monitor output signal is flat, that is, we did not include
equalization for the monitor in the 800 Mixer since this
equalization is usually external to the mixer and is best
performed on the stage itself, which is generally at some
considerable distance from the mixer. It is because the
mixer is usually located remotely from the performing
area that it is sometimes difficult for the monitor
equalization to be performed at the mixer.
The METER SET CONTROL enables the VU
meter to be adjusted for proper indication with any
power amplifier, tape recorder, or other equipment
driven by the mixer. If your power amp, tape recorder,
etc... has YU meters, the level set control can be ad-
justed to track the S00 VU meter with a constant inpul
signal, i.e., set the 3900's meter to read "0" VU al the
same level as the external equipments VU does. With
equipment that has LED overload indicators, the 900's
meter should be set to zero VU at the point where the
LED peak overload indicator initially lights up.
If the equipment being fed by the 900 has no max-
imum level indicator you should refer any adjustment of
VU meters to a properly equipped sound technician to
avoid problems in matching VU readings with maximum
output and/or modulation.
You should be aware that we have designed the
900 Mixer to be able to drive power amplifiers with
VERY low input sensitivities of 2 volts or higher.
Because of the high output capability of the 200, it may
appear that the 800 is excessively noisy when plugged
into power amplifiers with high input sensitivity such as
the Peavey 260 or 800 Boosters which require only %
volt for FULL output. The extra gain designed into the
200 to allow use with the less sensitive power amps
should NOT be interpreted as poor design bul as ad-
ditional gain capability. It is possible to use “high gain”
power amps with very good results by generally using
less channel and master gain, or by decreasing the
power amp's sensitivity by turning down the power
amp's level control
REAR PANEL - The S00 Mixer rear pane! features
a complete patching panel for various output and input
functions, as well as the microphone input connectors
for each channel.
Each channel's input connectors are labeled with
its identification number, as well as an indication of
whether the input is for high (16) or low (17) impedance.
The high impedance connectors are standard phone
jacks. The low impedance connectors are of the can-
non type, three conductor connector to be used lor low
impedance microphones only, and will accept 150 to
600 ohm mics.
AUXILIARY INPUTS - There are three auxiliary in-
puts on the 900 Mixer.
The MAIN AUXILIARY INPUT (18) is the input to
the main mixing buss of the 800 Mixer. This input mixes
a signal with the main buss at the same point as the in-
dividual channels and may be used when patching two
mixers together, or whenever an additional signal is
added to the main mix. The main auxiliary input can
also be thought of as an additional channel and can
even be used with a high impedance microphone as a
signal source.
put to the monitor mixing buss of the 900 Mixer. This in-
put mixes a signal with the monitor buss at the same
point as the individual channels and is to be used when
patching two mixers together or any time access is
needed to the monitor buss in order to place a particular
signal in the monitor system.
The EFFECTS AUXILIARY INPUT (20) is the input
to the effects mixing buss of the 900. This input mixes a
signal with the effects buss at the same point as the in-
dividual channels and is to be used when patching two
mixers together or any time access is neeced lo the
effects mixing buss.
The EFFECTS RETURN (26) is the input jack for
patching in external signals of various kinds. This input
is high impedance with adequate gain to handle low
level signal sources such as certain echo units and high
impedance mics. Actually, this input is an additional
channel without equalization or sends that feeds into the
main mixing buss as do the other channels. The level
control for this input is the Effects Return (15) located in
the front panel master section.
The MAIN OUTPUTS (21) are located on the rear
panel and are standard '% phone jacks. The oulputs are
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unbalanced and are capable of 5 volts RMS into 10K
ohms load impedance. These levels are capable of
driving most commercial power amplifiers or other aux-
liary equipment to full performance by a wide margin
and should allow a more than adequate amount of
headroom in nearly any application.
The MONITOR QUTPUTS (22) are unbalanced
and are capable of 5 volts RMS into 10K ohms load im-
The EFFECTS HIGH QUTPUT (23) is capable of 2
volts RMS into 10K ohms load and can be used to drive
an additional power amplifier and speaker system from
the effects buss to obtain an additional monitor.
The EFFECTS LOW QUTPUT (24) is a lower level
signal than the effects high and is intended to drive the
input of an effects device such as an echo unit, phasor,
etc. It is capable of 0.4 volts RMS into 10K ohms.
Both the effects high and effects low outputs are
controlled by the effects level control and both jacks
can be used simultaneously.
with an auxiliary footswitch to enable the operator to
defeat the reverb function of the mixer remotely.
The POWER SWITCH (28) is the type that enables
the operator to easily reverse the polarity of the line
(mains) cable, thus yielding the ability to minimize hum
by proper polarization of the power supply (mains) con-
nection. One of the ON positions will result in the lowest
hum level and/or the least noise when unbalanced high
impedance microphones are used, and this position
should be used.
You must polarize the power (mains) supply to
achieve maximum performance in each location the
mixer is used In.
SPECIAL NOTE...Some export versions of the 900
Mixer do not have the two-way switch, and this informa-
tion should be disregarded for those models.
provided for durability under road conditions. This is a
three wire approved cord, and it is NOT advisable to
remove the ground pin under ANY circumstances. If
you should find it ‘necessary to operate the system
where the proper three wire receptacles are NOT
available, you should use a three-to-two wire adapter.
Frequency Response:
20 Hz - 20 kHz + 2 dB @ 2v rms output (+8 dBm)
Total Harmonic Distortion:
0.1% THD 20 Hz - 10 kHz @ 2v rms output {+8 dBm)
Equivalent Input Noise:
Low Z input, —123 dBv © 150 ohms (0.7 uV)
High Z input, — 80 dE below 2v rms @ 20 dB gain
Input Attenuator:
Total gain of mixer @ 0 dB attenuation =60 dB
Main & Monitor
Effects High: Unbalanced, 2v rms into 10 K ohms
Effects Low: Unbalanced, 0.4Y rms into 10 K ohms
for external effects units
Low impedance unbalanced microphone 600 ohm (cannon plug)
High impedance unbalanced line 50 K ohm (pheno plug)
Continuously variable from 0 dB to —40 dB operational on mic or line inputs
Unbalanced, 5v rms into 10 K ohms, 2v rms into 600 ohms (+8 dBm)
Infinitely variable boost & cut, +15 dB @ 100 Hz & 5 kHz ea. channel
+15 dB @ 50 Hz & 10 kHz Master
Built-in reverb unit with contour control, effects out & return capability
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Specifications and features published in this manual are subject to change without notice.
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