Bogen CAM8PRO Guide

CAM8PRO Mixer
Installation and Use Manual
© 2011 Bogen Communications, Inc.
All rights reserved.
54-2034-01D 1207

Notice
Every effort was made to ensure that the information in
this guide was complete and accurate at the time of print-
ing. However, this information is subject to change.
Important Safety Information
Always follow these basic safety precautions when
installing and using the unit:
1. Read all instructions before installing or operating the unit.
2. Follow all warnings and instructions marked on the
product.
3.
DO NOT block or cover the ventilation slots and openings .
They prevent the product from overheating. DO NOT
place the product in a separate enclosure or cabinet,
unless proper ventilation is provided.
4. Never spill liquid on the product or drop objects into the
ventilation slots and openings. Doing so may result in
serious damage to the components.
5. Repair or service must be performed by a factory
authorized repair facility.
6.
DO NOT use the product near water or in a wet or damp
place (such as a wet basement).
7. DO NOT use extension cords. The product must be
installed within 6 feet of a grounded outlet receptacle.
8. DO NOT install telephone wiring during a lightning storm.
9. DO NOT install telephone jacks in a wet location unless
the jack is specifically designed for wet locations.
10. Never touch uninsulated wires or terminals, unless the
line has been disconnected at the paging or controller
interface.
11. Use caution when installing or modifying paging or
control lines.
Maintenance & Service
Caution
There are no user-serviceable parts within the unit.
Have all internal servicing performed by a qualified
technician. The warranty will become void if
repairs are made by other than the Bogen Service
Department or an authorized service agency.
Our Applications Engineering Department is available to
help you troubleshoot problems with your Bogen equip-
ment. Engineers are available from 8:30 AM to 6:00 PM,
Eastern Standard Time. Phone [phone].
Service can be obtained from our factory service depart-
ment. No merchandise may be returned for repair without
prior written authorization. Please contact our factory
service department at 1-800-999-2809 for a RA number.
Only merchandise specified in the return authorization
form can be returned to obtain warranty or non-warranty
repair. When shipping your unit, pack your system well
using the original shipping carton or a similar container
and filler material to prevent damage in transit. Send the
unit fully insured and prepaid via UPS or other responsi-
ble carrier.
Page 2

Contents
INTRODUCTION ......................................................................................................................................................4
Safety Instructions ........................................................................................................................................5
QUICK START ..........................................................................................................................................................6
PANEL DESCRIPTIONS........................................................................................................................................7-9
Front Panel ..................................................................................................................................................7
Rear Panel....................................................................................................................................................8
Helpful Hints ................................................................................................................................................9
INSTALLATION ..................................................................................................................................................10-11
OPERATION ......................................................................................................................................................12-18
Troubleshooting Gain Structure ..................................................................................................................13
Recommended Input Wiring Methods ........................................................................................................14
Fine Tuning ................................................................................................................................................15
Compressor/Limiter ....................................................................................................................................16
Special Features Activation ........................................................................................................................17
Jumper Options ..........................................................................................................................................18
TROUBLESHOOTING TIPS ..................................................................................................................................19
GLOSSARY ............................................................................................................................................................20
TECHNICAL INFORMATION ............................................................................................................................21-22
Specifications..............................................................................................................................................21
Block Diagram ............................................................................................................................................22
Page 3

Introduction
CAM8PRO
Page 4
This manual covers installation of the CAM8PRO. It was manufactured to ensure the highest
quality audio signal production and control, while still incorporating simple-to-use features.
This manual is designed to familiarize you with the features of your new Bogen CAM8PRO
mixer and to guide you through its installation and operation.

Bogenʼs CAM8PRO mixer is electrical equipment, so take all the precautions usually taken when installing and using
electrical equipment (see inside front cover). To protect both the users and the equipment, pay particular attention to:
• Grounding - Make sure both the mixer and the devices connected to it are properly grounded.
• Power Supply - Use only the power supply provided or one that meets the manufacturerʼs specifications.
• Cords and Cables - Route all cords and cables so that they will not be tripping hazards or subject to damage (from being
run over or pinched) that could cause them to become shock hazards. Pay particular attention to cords at plugs, conven-
ience receptacles, and the point where they enter the mixer.
Safety Instructions
Page 5

Quick Start
1. Unpack and Connect (See page 10 for more details).
A. Check mixer for shipping damage.
Rack Mounting: To mount the CAM8PRO to a 19” rack, lift the unit up to the front
of the rack and secure it to the front of the rack with the necessary screws (not
included with this unit).
B. If special features (see page 17) are to be used, they must be set before the
mixer is mounted.
C. Turn off both mixer and amplifier and turn all volume controls to zero.
D. Connect inputs and set the input pad switch for each channel at the appropriate
level (either MIC or line). Make sure that the bus selector is set for Main Out.
E. Connect output(s) and set the main output pad switch at the appropriate level
(either MIC or line). (Auxiliary output is line-level only.)
2. Power and Set Up (See pages 10-14 for details.)
A. Connect mixer AC power supply.
B. Turn volume controls down, then power up mixer and amplifier.
Note: Mixer will produce signal transients on power up and power down. Always
turn the mixer on first before turning on the amplifier and always turn the amplifier
off first before turning off the mixer.
C. Adjust Main/AUX out controls to the 2 oʼclock position. Then turn amp up to
normal level while performing audio test.
D. Adjust input gain/trim control for each channel to get a meter reading within the
green area.
E. Adjust individual channel volume controls to the 2 oʼclock position.
3. Fine Tuning (See page 15 for details).
A. In the event of excessive bass, press Low Cut filter switch(es) “on.”
B. If condenser mics are used, press phantom power switch “on” (turns phantom
power on for all inputs set to MIC position).
C. In the event of occasional excessive output level, press Compressor/Limiter
switch “on”.
Page 6

CAM8PRO Front Panel
1. Main/Auxiliary Bus Selector (one per channel)
A 4-position switch which selects destination of channel input. Input can be
routed to: a) the main bus (M-up, A-down); b) the auxiliary bus (M-down,
A-up-shown at right); c) both the main and auxiliary buses (both up);
or d) neither bus (both down).
2. Channel Volume Control Knob (one per channel)
Controls the volume of the channel input to any and all outputs simultaneously.
3. Low Cut Switch
Helps eliminate low frequency noise (100 Hz 18 dB/octave).
4. Main Output Compressor/Limiter Switch and LED
Note: Works only on main bus. Reduces distortion of the main output (due to clipping) by
controlling its dynamic range. When the LED (red) is lit, the Compressor/Limiter is on.
The brighter the LED, the more the signal is being compressed.
5. Main Output Volume Control Knob
Controls the output signal volume of the main bus.
6. LED Bar Graph Output Meter
Displays output signal level in decibels, ranging from -18 (green) to +12 (red) VU.
0 VU = +4 dBm. This meter can be set to indicate the signal level of either the main or aux-
iliary bus and to indicate either the average or peak signal. (See page 18 for details.)
7. Threshold Control
Screw-pot adjustment sets the signal level (-20 to +20 VU; factory setting is 0 VU) at which
the Compressor/Limiter becomes active.
8. Ratio Control
Screw-pot adjustment sets the amount of compression (0-100%; factory setting is 100%)
of the signal above the threshold.
9. Auxiliary Output Volume Control Knob
Controls the output signal volume of the auxiliary bus output and to the headphones.
(There is no connection between this bus and the Compressor/Limiter.)
10. Headphone Jack
A 1/4 inch-diameter TRS mono-only jack for the connection of headphones. (Only moni-
tors AUX bus.)
11. Power Indicator LED
LED displays mixerʼs powered state. Lit when power is on. Not lit when power is off.
12. Power Switch Button
Push button to turn unit on (“in” position); push again to turn unit off (“out” position).
Page 7
M A
Bus
+
-
Front Panel Descriptions
Power
Ratio
0100
AUX
0 +3 +12+6
MAIN
-12-18 -6 -3
Threshold
On
8Cut
Low
Off
-
+
M.A
BUS
Low
Cut
7Limit Headphone
-
+
-
+
Low
Cut
6
BUS
M.A
-
+
5
M.A
BUSCut
Low
Cut
Low
+
-
4
M.A
BUS
Low
Cut
3
-
+
Low
Cut BUS
M.A
2
-
+
-
+
Cut
Low
1
M.A
BUS BUS
M.A
BUS
M.A
CAM8PRO
25 7 8 9
13 4 610 11 12

CAM8PRO Rear Panel
1. Ground Connection on Rear Panel
Access to ground.
2. AC Power Jack
Mixer power supply input.
Accepts a 4-pin DIN connection from
a 17V CT 1.5 Amp transformer.
3. Phantom Power Switch
When activated, supplies 30V DC power to all inputs set to MIC level.
4. Auxiliary Bus Output
Balanced, line-level, connection to auxiliary output bus.
5. Main Output Microphone/Line Switch
Selects main output to be either MIC (-50 dBμ) or line (0 dBμ) level.
6. Main Bus Output
Balanced connection to main output bus.
7. Auxiliary Input
Balanced, buffered, uncontrolled, line-level terminals for additional (ninth) input connection
directly to the summing buses selected by internal jumpers. The factory default is both
jumpers installed. (See page 18 for details.)
8. Input Gain/Trim Control Screw
Adjusts gain of input stage, over a range of 40 dB.
9. Input Pad Microphone/Line Switch
Selects either MIC (-50 dBμ) or line (0 dBμ) level for corresponding input connection.
10. Input
Balanced input connection (pluggable terminal strip).
+
+
+
+-
--
-G+
+
+
+
G-
--
-
+
+
+
+-
--
-G+
+
+
+
-
--
-G
+
+
+
+-
-
-
-
G+
+
+
+-
-
-
-G
+
+
+
+-
-
-
-
G+
+
+
+-
-
-
-G
-
-G - -+ +
+
++
+
+
+
-
-
-
-
G
+- +- +- +-G
12
Trim
Mic
Line
34
Mic
Line
TrimTrim
Mic
Line
5
Trim
Mic
Line
6
Mic
Line
Trim
7
Trim
Mic
Line
8
Trim
Mic
Line
MAIN
0dB
-50dB
Off
On
AUX OUT AUX IN
AC
Power
Ground
Phantom
17VCT
Mic
Line
Trim
2
1
3 5 9 10
467 8
Page 8
Rear Panel Descriptions
No connect
Center
AC AC

Helpful Hints
Electrical equipment operates best in a clean, dry, well-ventilated environment free of
vibration and electromagnetic fields. The following are some guidelines to achieve
optimal performance.
Avoid placing the mixer and cables near heat sources. Be particularly aware of other
audio equipment, such as amplifiers, which can produce a great deal of heat when
operating.
To minimize hum in the system, avoid placing the mixer and cables near radio fre-
quency devices and other electromagnetic field sources such as:
• Fluorescent lights
• Electrical motors
• SCR dimmers
• AC power lines, etc.
Note: Always use 2-conductor shielded cable to reduce EMI or RF interference to the
Line/MIC inputs.
Keep the mixer and other equipment clean and free of dust by wiping occasionally
with a soft, damp cloth.
Protect the mixer from electrical damage by disconnecting it from the power source
whenever it will be unused for a week or longer.
The Bogen mixer is easy to install and adjust. The only tools needed are:
1. Slotted screwdriver
2. Phillips-head screwdriver
Page 9

Installation
Note: Take the mixer out of the box and inspect for shipping damage. If there is obvious
physical damage to the outside of the mixer, contact the supplier of the mixer before you
begin installation.
Rack Mounting: To mount the CAM8PRO to a 19” rack, lift the unit up to the front of the
rack and secure it to the front of the rack with the necessary screws (not included with this
unit).
A. Turn all mixer Volume Control Knobs [Channel(s) (1), Main (2), and Auxiliary (3)] to zero.
Turn amplifier(s) volume controls to the 7 oʼclock position.
B. Connect Inputs.
Connect lead into desired pluggable terminal strip (6) on rear panel.
Press Input Pad Microphone/Line Switch (5) to appropriate position: “in” for line input or
“out” for MIC input. Note that the input from some mics is actually close to line level
(-20 dB) and for such mics the switch should be at “Line.” Set switch for all unused chan-
nels at Line level. The Auxiliary Input (4) is Line level only.
Page 10

C. Connect Output: Make a connection between Main Bus Output Terminals (3) and an
input jack of an amplifier. Press Main Output Microphone/Line Switch (2) to appropri-
ate position: “in” for line-level output (0 dBμ) or “out” for mic-level (-50 dBμ) output.
If desired, also connect Auxiliary Bus Output Terminals (1) to a second destination
device. The auxiliary output is line-level only.
D. Connect mixer power supply to an AC power outlet and to the AC Power Jack (4)
(located on far left side of rear panel).
E. Power up mixer:
Press Power Switch (8) to “in” position. [Power Indicator LED (7) will be lit if mixer is
powered.] Set Main Output Volume Control Knob (5) to 2 oʼclock. If auxiliary output is
desired, also set Auxiliary Output Volume Control Knob (6) to 2 oʼclock.
Power up amplifier.
Note: Mixer will produce signal transients on power up and power down. Always turn the
mixer on first before turning on the amplifier and always turn the amplifier off first before
turning off the mixer.
Page 11
+
+
+
+
-
-
-
-
G
+- +- +- +-G
MAIN
0dB
-50dB
Off
On
AUX OUT
Phantom
13
2

Operation
The primary goal when establishing the gain settings of the mixers is to have each channel
operating at the maximum gain without clipping, while leaving adequate headroom on the
volume control knob.
The channel Input Gain/Trim Control (1) on the rear panel of the mixers directly controls
the microphone pre-amplifier gain available at each channel.
The Volume Control (2) on the front panel controls how much of the gain is routed to the
main output stage. The front panel controls should optimally operate between the 9 and
2 oʼclock position when gain structure is correct (see example on page 13).
The Main Output Volume Control Knob (3) on the front panel controls the mixerʼs final
amplifier stage to the master output. This control should optimally operate between the
9 and 2 oʼclock positions when gain structure is correct.
With all channels operating, the main output meter should show a signal output range
between 0 and +6 VU. Adjust the main output control accordingly. If the output occasion-
ally peaks in the range of +6 and +12 VU, activate the Compressor/Limiter (see page 16).
The amplifier for the loudspeakers should be the final control for establishing volume levels.
Note: The channel Input Gain/Trim Controls are factory preset to produce a 0 dBμ
signal level at the master output when the front panel volume controls are set at the
2 oʼclock position. This setting is optimal with most input devices.
+
+
+
+-
-
-
-G
6
Mic
Line
Trim
1
-
+
-
+
Cut
Low
1
M.A
BUS BUS
M.A
2
Page 12

Troubleshooting Gain Structure
If the procedure followed to this point does not give satisfactory results, follow the appro-
priate adjustment sequence below:
If channel clipping occurs
If the signal is clipping or producing audible distortion, the gain is too high. Reduce the
Input Gain/Trim Control (rear panel) by turning it counterclockwise until clipping does not
occur. Also make sure that the new setting of the gain control offers a usable control range
between the 9 oʼclock and 2 oʼclock positions on the front panel volume control knob.
If channel volume is too low
If a channel must be set above the 2 oʼclock position to provide adequate volume, the input
gain setting is too low. Turn the volume control knob to the 1 oʼclock position and increase
the input gain by turning the input gain/trim control clockwise until clipping occurs, or VU
meter is over 0 VU. Then adjust the gain to a setting just below the clipping level.
If channel volume is too high
If a channel is not clipping but must be set below the 9 oʼclock position to achieve the proper
volume level, the input gain control setting is too high. Reduce the Input Gain/Trim Control
by turning it counterclockwise. Set the volume control knob to the 9 oʼclock position and
continue to adjust the gain control until the desired volume level is achieved.
Page 13
Range for optimal volume control operation
settings (indicator positions).

Recommended Input Wiring Methods
These are the best ways to connect sources to the mixer. The mixer input is always
balanced. From the drawings below choose the wiring method for your input device (either
balanced or unbalanced).
Balanced Source to Balanced Input - Method 1 (Normal)
Shown below is the normal wiring method for a balanced source device. It has +6 dB gain
and excellent ground current and noise rejection.
Balanced Source to Balanced Input - Method 2
If the method above does not work in your application, use the wiring shown below. This
method can solve certain ground loop problems. It has +6 dB gain and good noise and
ground loop rejection.
Unbalanced Source to Balanced Input - Method 1
For an unbalanced source device, the drawing below shows the best wiring method.
Because of the design of the mixer, this wiring provides a slight (+6 dB) boost, and
moderate noise and ground loop rejection.
Unbalanced Source to Balanced Input - Method 2
For an unbalanced source device, the drawing below shows an alternative wiring method.
Because the grounding of the minus input is not to the mixer ground, this method does not
provide the +6 dB boost. Ground current and noise rejection is good.
-
+
-
+
+
-
Gnd
Balanced Source G
-
+
-
+
+
-
Gnd
Balanced Source No connect G
-
+
-
+
+
Gnd
Unbalanced Source G
-
+
-
+
+
Gnd
Unbalanced Source G
Page 14

Fine Tuning
Low Cut Switch
To remove excessive bass from an individual channel, press the Low Cut Switch (1) for
that channel.
This feature helps eliminate low frequency noise (signals of 100 Hz and below, such as
background rumble from ventilation systems, etc.) and is used primarily with mic-level
input. It is particularly effective when handheld mics are used.
Phantom Power
If a condenser microphone(s) is not independently powered, press Phantom Power
Switch (2) to the “on” position.
The phantom power switch will power condenser (capacitor) mics through the mic cable.
Depressing the button simultaneously applies phantom power to all channels set to
mic-level.
-
+
-
+
Cut
Low
1
M.A
BUS BUS
M.A
1
Page 15

Compressor/Limiter
The Compressor/Limiter (1) is a dynamic range controller that can be used to compen-
sate for signals that may sound unnatural or cause audible distortion. This is indicated by
the LED Bar Graph Output Meter (3) occasionally exceeding +12 VU (red).
Note: The Compressor/Limiter only affects the main channel.
A Compressor is used to slightly reduce the dynamic range of a signal. This effect is per-
ceived to quiet loud sounds and boost quiet sounds. A compressor smooths transients.
A Limiter is used to prevent a signal from exceeding a certain level. This function guards
against amplifier or recording level overloads. The Compressor/Limiter is activated by
pressing the Main Output Compressor/Limiter Switch.
This dynamic controller allows for compression and limiting functions by controlling
threshold and ratio.
The Threshold Control (2) is a screw potentiometer that sets what signal level will acti-
vate the Compressor/Limiter. It has a range of -20 to +20 dB.
The Ratio Control (4) is a screw potentiometer that sets the compression ratio that will be
applied when the signal exceeds the threshold. It has a range from 0% to 100%. A
Compressor becomes a Limiter when the compression ratio is 10:1 or greater.
The factory setting for the threshold is 0 VU (+4 dB), but this is variable (from -20 dB to
+20 dB) and can be changed by adjusting the Threshold Control. Likewise, the factory
setting for the compression ratio is 100% (at this maximum setting, the circuit performs the
limiter function), but can be set to between 0 and 100% by adjusting the Ratio Control.
Note: The LED Bar Graph Output Meter can be used to view the effects of adjusting the
Compressor/Limiter controls. Turn off power amplifiers while performing these adjust-
ments.
Warning: If the amplifier/speaker combination being used is such that the speak-
er(s) can be overdriven to failure, always operate the mixer with the Output Limit
Switch in the “on” position and the ratio should be set at 100%.
Page 16

Special Features Activation
The CAM8PRO mixer has several built-in features which are easily activated by making
adjustments inside the mixer chassis. Changing the selection of all built-in features
requires only the correct placement of internal jumpers or varying the settings of an
internal potentiometer.
Note: All the internal components — jumpers and potentiometers — to which adjustments
are needed for built-in features are highlighted within dashed areas in the drawing below.
Warning: Adjustments made to any other internal components may void the warranty.
Page 17
AUX IN MAIN OUT AUX OUT POWER
LED BAR GRAPH METER
REAR
LEFT RIGHT
FRONT
Power
Switch
Button
AUX
OUTPUT
VOLUME
KNOB
MAIN
OUTPUT
VOLUME
KNOB
OUTPUT
LIMITER
SWITCH
JP4 JP3
JP2
JP1

Jumper Options
Changing Jumper Settings
To change a jumper setting, remove the ten screws secured to the top of the mixer. After
removing the top of the mixer, locate the jumper to be changed by referring to the drawing
on page 17. Jumpers are included from the factory in positions: JP1: 1-3, JP2: 2-4,
JP3: 1-3, JP4: 1-3, 2-4..
Warning: Disconnect AC Power before opening case.
Bar Graph Options
The mixerʼs meter can be configured to meter the output of either the main or auxiliary
bus. In addition, the bar graph can be configured to register either the peak or average
level of the audio signal.
JP2
The LED Bar Graph Output Meter can be set to register either the main or auxiliary
bus output audio signal. The choices are:
MAIN installed: The Bar Graph meters the main bus output. This is the factory default.
AUX installed: The Bar Graph meters the auxiliary bus output.
Note:The meter will operate only when a jumper is in one of these two positions.
JP3
The LED Bar Graph Output Meter can be set to register either the peak or average
level of the output audio signal. The choices are:
PEAK installed: The Bar Graph meter registers the peak level of the audio output.
AVG installed: The Bar Graph registers the average level of the audio output.
This is the factory default.
Note:The meter will operate only when a jumper is in one of these two positions.
Bus Routing Options
AUX In Jumpers: JP4
These jumpers determine the destination of the Auxiliary Input. The choices are:
MAIN installed: Auxiliary Input is routed to Main Output.
AUX installed: Auxiliary Input is routed to Auxiliary Output.
MAIN and AUX both installed: Auxiliary Input is routed to both Main and AUX outputs.
This is the factory default setting.
AUX Source Jumpers: JP1
These jumpers determine which of two gain controls are used to control the level of the
AUX output. The choices are:
INT installed: AUX output gain is controlled by the internal pot, “AUX Pregain Pot” R342
(see page 17 for location). The front panel AUX output volume knob continues to
independently control the gain of the headphone amplifier jack on the front panel. This
setting is typically used in a linking situation where the output from a mixer must remain
fixed, since JP1 makes the output of that mixer tamperproof (from the front panel).
With INT installed, the front panel AUX volume knob controls only the headphone level.
EXT installed: AUX output gain is controlled by AUX volume knob on front panel.
The 1/4-inch Headphone amp is also controlled by the AUX volume knob, but not
independently of the AUX output.
This is the Factory Default.
Note:Never install jumpers in both positions INT and EXT.
Page 18

Troubleshooting Tips
NO POWER
Check the connections between the mixer and the power supply and the external AC
power supply. Examine the 4-pin connector as shown on page 22.
Check the wall outlet.
NO SOUND
• Make sure the MIC/Line switch is in the proper position. (This is the most likely cause.)
• Make sure both the master and channel input controls are turned up.
• Check that the source signal cable(s) is properly connected and undamaged.
• Adjust Input Gain/Trim Control potentiometer(s) to increase gain.
• If there is still no sound, try changing input source(s) to different channel(s).
DISTORTED SOUND
• Turn down the master volume control. If distortion persists, input channel(s) gain is the
likely cause.
• Check position of all line/MIC switches.
• Determine the distorting input channel(s) by checking them one at a time.
• Decrease gain of input channel(s) causing distortion by turning the screw on the rear
panel.
EXCESSIVE HISS or HUM
Hiss: Make sure the volume control knobs for all the unused channels are turned all the
way off (i.e., at the 7 oʼclock position).
• Make sure that all unused input channels have the MIC/Line switch in the Line position.
• Make sure the MIC/Line switch is in the correct position for both the inputs and the main
output.
Hum: MIC lines can easily cause hum. Make sure to locate them away from vibration and
magnetic field sources (motors, power supplies and lines, and data lines).
Check MIC lines, especially the shield, for damage.
Another common source of hum is a ground loop, which can result from connecting two or
more powered devices together.
Turn both the Main and Auxiliary volume controls down. If the hum is still present, the
ground loop or other cause is not in the mixer, but in the devices that come after it in the
audio path or in the connection between the mixer and following equipment. (If the hum
disappears, then the cause is either in the mixer or in one of the inputs to the mixer. Turn
each of the volume controls [both the individual input channels and the two buses] down
independently, to determine which one is the source of the hum.)
Check for unbalanced connections; use balanced connections, if possible. For all
unbalanced connections, try disconnecting the signal line ground to eliminate multiple
ground paths.
Page 19

Page 20
Glossary
Auxiliary Input - Accepts only a balanced, line-level input (unlike the 8 channels); the aux-
iliary input has no volume control.
Compression Ratio - The ratio of the output level above the threshold level to the input
level above the threshold.
Compression Threshold - The volume level, in dB, which is set as the optimum device
operating level, and above which the Compressor/Limiter begins to operate.
Compressor - A special type of limiting device, which controls the total volume level of a
signal by compressing the part of the signal which exceeds a predetermined threshold.
The threshold can be varied.
Gain/Trim Control - Gain is the ratio between the input and output signal levels. Trim is
the adjustment of the gain of the input stage to offset the differences between input signal
levels.
Ground Loop - A condition which can occur when several ground pathways exist between
two or more devices and which can cause hum in the audio signal.
Jumper - A short length of conductor used to connect pins electrically.
Limiter - A device that severely (at rates greater than 10:1) restricts the upper dynamic
range of a signal, by regulating the rate of increase of an input signalʼs amplitude so that
it will not exceed a predetermined threshold.
Line/Microphone Level - The two signal level ranges at which the mixer accepts input.
MIC level is usually -50 dBμ and Line level is usually +4 dB.
Low Cut Switch - Removes the lower-frequency (<100 Hz) components, which cause
rumble, from a signal.
Phantom Power - A method of powering condenser microphones by sending DC current
over the same MIC cable that carries the audio signal. Called “Phantom” as there is no
visible power cord and the voltage is not perceptible in the audio signal.
Pot - Potentiometer.
RCA Connector - An unbalanced line level connection, also known as “phono connector.”
Summing Junction - The point in the CAM8PRO circuitry where the audio signals are
mixed.