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Commercial Audio 5-Channel
70V/100VMixer Amplifier with Microphone Priority
PROT OUTPUT LEVELTEMP
2
468
1 0 1 2
POWER
MIC 1 MIC 2 MIC 3 AUX 1 AUX 2 BASS TREBLE
MIC 1
5
4 6
3
2
1
4 6
7
3
8
2
9
1
0
10
0
5
4 6
3
7
2
8
1
9
0
10
P/N 18803
P/N 14886
P/N 18805
5
5
5
4 6
7
8
9
0
10
4 6
3
2
1
0
|
60-Watt
|
120-Watt
|
240-Watt
7
3
8
2
9
1
10
0
-1 +1
-5
+2
+3
+4
+50-5
-1 +1
-2
-3
-4
7
-2
8
-3
9
-4
10
MASTER
5
4 6
3
+2
+3
+4
+5
7
2
1
9
0
10
ON
8
OFF
User’s Manual
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CONTENTS
SAFETY WARNINGS AND GUIDELINES ............................................................................................................................... 3
INTRODUCTION ........................................................................................................................................................................................ 4
FEATURES ...................................................................................................................................................................................................... 5
PACKAGE CONTENTS ......................................................................................................................................................................... 5
PRODUCT OVERVIEW ......................................................................................................................................................................... 6
Front Panel ............................................................................................................................................................................................. 6
Rear Panel ............................................................................................................................................................................................... 7
CONSTANT VOLTAGE VS LOW IMPEDANCE SPEAKER SYSTEMS .............................................................. 8
WIRE PREPARATION ............................................................................................................................................................................ 9
INSTALLATION AND SETUP ......................................................................................................................................................... 10
INSTALLATION NOTES ..................................................................................................................................................................... 13
FUNCTIONAL BLOCK DIAGRAM ............................................................................................................................................. 14
SPECIFICATIONS .................................................................................................................................................................................... 15
REGULATORY COMPLIANCE ...................................................................................................................................................... 16
Notice for FCC .................................................................................................................................................................................. 16
Notice for Industry Canada ................................................................................................................................................... 16
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SAFETY WARNINGS AND GUIDELINES
Do not install this device on an unstable surface where it could fall and cause
either personal injury or damage to the device and/or other equipment.
This device is intended for indoor use only.
Do not expose this device to water or moisture of any kind. Do not place drinks
or other containers with moisture on or near the device. If moisture does get in
or on the device, immediately unplug it from the power outlet and allow it to
fully dry before reapplying power.
Do not touch the device, the power cord, or any other connected cables with
wet hands.
Do not expose this device to excessively high temperatures. Do not place it in,
on, or near heat sources, such as a fireplace, stove, radiator, etc. Do not leave it
in direct sunlight.
This device ventilates excessive heat through the slots and openings in the case.
Do not block or cover these openings. Ensure that the device is in an open area
where it can get sufficient airflow to keep from overheating.
Do not place or install this device in an area where it can be exposed to
excessive amounts of dust, humidity, oil, smoke, or combustible vapors.
Use only in a well-ventilated area. Do not use in close, confined spaces.
Prior to operation, check the unit and power cord for physical damage. Do not
use if physical damage has occurred.
Before plugging the unit into a power outlet, ensure that the outlet provides the
same type and level of power required by the device.
This device uses a grounded power cord and requires a ground connection for
safe operation. Ensure that the power source has a proper ground connection.
Do not modify the plug or use a "cheater" plug to bypass the ground connection.
Disconnect the unit from the power source when replacing the fuse. Replace the
fuse only with the same type.
Unplug this device from the power source when not in use.
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Take care to prevent damage to the power cord. Do not allow it to become
crimped, pinched, walked on, or become tangled with other cords. Ensure that
the power cord does not present a tripping hazard.
Never unplug the unit by pulling on the power cord. Always grasp the connector
head or adapter body.
Ensure that power is turned off and disconnected before making any electrical
connections.
Clean using a soft, dry cloth only. Do not use chemical cleaners, solvents, or
detergents. For stubborn deposits, moisten the cloth with warm water.
This device has no user serviceable parts. Do not attempt to open, service, or
modify this device.
If using this amplifier to drive a 70V or 100V speaker array, ensure that the total
wattage rating of the speaker array does not exceed 80% of the amplifier's rated
RMS power level, i.e., 48 (18803), 96 (14886), or 192 (18805) watts, depending on
model
Because high voltage is present on the 70V and 100V speaker output terminals,
always use the included terminal cover to prevent electric shock from accidental
contact.
INTRODUCTION
Thank you for purchasing this 5-Channel 70V/100V Mixer Public Address Amplifier!
This amplifier features three microphone inputs and two auxiliary inputs, each of which
is active and mixed into the line and speaker level outputs. When an EMC input trigger
is detected, all outputs except MIC 1 are muted, allowing for the clear broadcast of
important messages. The amplifier can drive a speaker array consisting of one or more
speakers presenting a 4~16 ohm load or to one or more 70V or 100V speakers
connected in parallel as part of a large public address system.
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FEATURES
5-channel (3 microphone and 2 line) mixer/amplifier
Amplifier rated for 60 (18803), 120 (14886), or 240 (18805) watts
70V, 100V, and low impedance 4~16 ohm speaker output options
Built-in rack mount ears and 2U height for mounting in a standard 19" equipment
rack
Unbalanced front panel input for MIC 1
Both balanced XLR and unbalanced TRS and RCA rear panel inputs for MIC 2 and
MIC 3
Phantom power option for MIC 2 and MIC 3
Two unbalanced RCA auxiliary/line inputs
One EMC priority input
Master volume, bass, and treble controls
Front panel level controls for all inputs
0-30dB variable muting for all channels except MIC 1 when MIC 1 is in use
Built-in short circuit, over-current, and high temperature protection circuits
Line level output of mixed signal for connection to other devices
PACKAGE CONTENTS
Please take an inventory of the package contents to ensure you have all the items listed
below.
1x 5-channel 70V/100V mixer public address amplifier
1x AC power cable (NEMA 5-15 to IEC 60320 C13)
1x User's manual
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PRODUCT OVERVIEW
Front Panel
1. MIC 1 Input: Unbalanced stereo 1/4" (6.35mm) TRS microphone level input. This
input is never muted and always broadcasts, even when the EMC trigger is
detected.
2. MIC 1 / MIC 2 / MIC 3 Knobs: Mixing level controls for the three microphone
inputs.
3. AUX 1 / AUX 2 Knobs: Mixing level controls for the two auxiliary inputs.
4. BASS Knob: Master bass level control.
5. TREBLE Knob: Master treble level control.
6. MASTER Knob: Master volume level control.
7. ON / OFF Switch: Power switch.
8. POWER LED Indicator: Power LED indicator illuminates when power is applied.
9. OUTPUT LEVEL LED Indicators: Output level meter.
10. PROT LED Indicator: If a short circuit, overload condition, or excessive
temperature condition is detected, the output will be disconnected and the
PROT LED will illuminate, indicating that the protection circuit is active. To reset
the protection circuit turn the amplifier off, then back on.
11. TEMP LED Indicator: If excessive temperatures are detected, the TEMP LED will
illuminate.
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Rear Panel
12. AC INPUT: Grounded AC power input and fuse holder.
13. OUTPUT: Speaker output terminals for 70V, 100V, and low impedance 4~16 ohm
speaker loads.
14. EMC INPUT: When a signal is detected on this input, all inputs except MIC 1 are
muted, allowing for clear broadcast of important messages.
15. MUTE: This knob controls the amount of automatic volume reduction that is
applied to all inputs except MIC 1 whenever a signal is detected on the MIC 1.
Unlike the total muting when an EMC trigger is detected, this only reduces the
volume of the other inputs, allowing you to talk over the other audio content.
The amount of signal reduction is from 0dB to 30dB.
16. MIC 2 / MIC 3: Unbalanced stereo 1/4" TRS microphone inputs.
17. MIC 2 / MIC 3 LINE INPUT: Unbalanced stereo RCA microphone/line level inputs.
18. AUX 1 INPUT / AUX 2 INPUT: Stereo line level RCA auxiliary inputs.
19. MIX OUT: Stereo line level RCA output of the final mix.
20. FAN: The cooling fan automatically turns on when the temperature reaches
+131°F (+55°C).
21. MIC 2 XLR GAIN / MIC 3 XLR GAIN: Use these knobs to control the amount of
gain applied to each of the two XLR microphone inputs.
22. MIC 2 +48V PHANTOM POWER / MIC 3 +48V PHANTOM POWER: Depress these
buttons to apply +48V phantom power to the respective XLR microphone input.
23. MIC 2 / MIC 3: Balanced mono XLR microphone inputs.
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CONSTANT VOLTAGE VS LOW IMPEDANCE SPEAKER
SYSTEMS
A constant voltage speaker system differs from a traditional low impedance (e.g., 8-
ohm) speaker system in that it uses a step-up transformer at the audio source to raise
the voltage and lower the current on the transmission line. At the speaker end, a step-
down transformer converts the signal back to a normal speaker level voltage. This
reduces power loss during transmission, which allows for the use of longer speaker wire
runs using smaller gauge wire.
Additionally, a constant voltage speaker system allows for the use of multiple speakers
on each channel, without the need for complicated impedance calculations and
configurations. In a constant voltage system, all speakers on a given channel are
connected in parallel and the complicated impedance calculations are replaced by
simple wattage calculations.
For example, if you want to connect two speakers per channel in a traditional 8-ohm
speaker system, you must either connect them in series, which results in an overall 16-
ohm impedance, or in parallel, which results in an overall 4-ohm impedance. In the first
case, the 16-ohms impedance effectively halves the output power of your amplifier,
resulting in lower overall volume levels. In the latter case, the 4-ohms impedance means
that your amplifier will have to work harder and must be rated as stable at 4 ohms.
Adding a third speaker to the mix would complicate it further, producing either a 24-
ohm or 2.67-ohm overall impedance. Note that very few amplifiers are stable under 2-
ohm loads, so that is usually not an option.
On the other hand, with a constant voltage system, you consider first the RMS output
wattage of the amplifier. This should be reduced by 20% to compensate for insertion
loss. Each individual speaker on a given channel is set to a value such that the total does
not exceed the rated power, less 20%. You do not need to worry about making the
total as close as possible to the limit; just ensure that the total does not exceed the
limit. For example, with the 120-watt model, the total load from speakers should not
exceed 96 watts.
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If all speakers are set to the same wattage value, they will all have the same volume
level. If one speaker is set to a higher wattage value, it will be louder than the others,
while a speaker set to a smaller value will be quieter than the others. This allows you to
compensate for the environment in which the speaker is placed. For example, a speaker
placed outside would need to be louder than a speaker placed in a small room.
WIRE PREPARATION
Regardless of which type of speaker array this amp will drive, you will need to use
speaker wire (not included) to connect the amp to the speaker array.
To prepare a length of speaker wire for connection, perform the following steps:
1. Use a wire stripper (not included) to remove about 3/8" (9.5mm) of insulation
from both conductors on one end of the wire.
2. Twist the exposed wire strands to ensure that the exposed section of wire
remains in a bundle.
3. Repeat steps 1-2 for the other end of the speaker wire.
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INSTALLATION AND SETUP
Perform the following steps to install and setup this amplifier. The following instructions
will assume connection of a CD player, an FM tuner, and three microphones. Note that
each input connection, except MIC 1, is optional.
1. Power off and unplug all equipment that will be connected to this amplifier.
2. Using a stereo RCA cable (not included), plug one end into the AUX 1 input on
the amplifier, then plug the other end into the stereo output of your CD player.
3. Using a stereo RCA cable (not included), plug one end into the AUX 2 input on
the amplifier, then plug the other end into the stereo output of your FM tuner.
4. Plug a microphone (not included) into the MIC 1 input on the amplifier.
Note that this must be either a dynamic microphone or a condenser microphone
with its own power source. For best results, use a microphone with a power
switch.
5. Plug a microphone (not included) into one of the MIC 2 inputs on the amplifier.
6. Plug a microphone (not included) into one of the MIC 3 inputs on the amplifier.
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7. Unless you are using a condenser microphone for MIC 2 or MIC 3, ensure that the
MIC 2 and MIC 3 +48V PHANTOM POWER switches are not depressed. If either
microphone is a condenser type, depress the appropriate PHANTOM POWER
switch.
Warning! Applying phantom power to a non-condenser microphone can damage
or destroy the mic.
8. Connect the output of your alarm trigger source to the EMC INPUT terminals on
the amplifier.
9. Connect a two-conductor speaker wire (not included) to the input terminals of
your speaker array.
Note: The speaker array can be one or more low impedance speakers connected
in such a way as to present a load between 4 and 16 ohms to the amplifier.
Alternatively, the array can be one or more 70V or 100V constant voltage
speakers connected in parallel with a total wattage rating of 48 (18803), 96
(14886), or 192 (18805) watts or less.
10. Connect the negative speaker wire lead to the COM terminal on the amplifier.
11. If using a low impedance speaker array, connect the positive speaker wire lead
to the 4-16Ω terminal on the amplifier. If using a 70V constant voltage speaker
array, connect the positive speaker wire lead to the 70V terminal on the
amplifier. If using a 100V constant voltage speaker array, connect the positive
speaker wire lead to the 100V terminal on the amplifier. Use only one of these
options.
12. Flip the terminal cover back over the speaker output terminals to protect from
electric shock due to accidental contact.
13. (Optional) If you want to send the mixed signal to another amplifier or other
device, plug one end of a stereo RCA cable (not included) into the stereo input
on your other device, then plug the other end into the MIX OUT RCA jacks on
the amplifier.
14. Ensure that the ON / OFF power switch on the front panel is in the OFF position.
15. Plug the included AC power cable into the C14 AC INPUT on the amplifier, then
plug the other end into a nearby AC power outlet.
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16. Plug in and power on all connected equipment. Start audio playback on the CD
player and FM tuner.
17. Ensure that the three MIC, the two AUX, and the MASTER knobs on the front
panel are fully counterclockwise. Ensure that the BASS and TREBLE knobs are set
to the mid-point, with the tick in the 12 o'clock position.
18. Flip the ON / OFF power switch on the amplifier to the ON position.
19. Slowly rotate the MASTER knob clockwise until the tick is in the 9 o'clock
position.
20. Slowly rotate the AUX 1 knob clockwise until audio material can be heard.
21. Adjust the positions of the AUX 1 and MASTER knobs until the volume is at the
desired level. This should be done in such a way that neither knob is near the
minimum or maximum part of its range, allowing for further adjustments to
increase or decrease the volume level from this audio source.
22. Rotate the AUX 2 knob clockwise until the volume level from the FM tuner is at
the desired level. In most cases this will be such that the volume levels from the
CD player and FM tuner are identical.
23. Turn on MIC 2. While speaking into the microphone, rotate the MIC 2 knob
clockwise until the volume is at the desired level.
Note: Depending on the microphone type and its output level, you may need to
adjust the MIC 2 GAIN control on the rear panel.
24. Turn on MIC 3. While speaking into the microphone, rotate the MIC 3 knob
clockwise until the volume is at the desired level.
Note: Depending on the microphone type and its output level, you may need to
adjust the MIC 3 GAIN control on the rear panel.
25. Turn off MIC 2 and MIC 3 and stop audio playback from the CD player and FM
tuner, so that no audio is present.
26. Turn on MIC 1. While speaking into the microphone, turn the MIC 1 knob
clockwise until your voice is at the desired level. Turn off MIC 1.
27. Restart audio playback from the CD player or FM tuner.
28. Turn on MIC 1. While speaking into the microphone slowly adjust the MUTE
control on the rear panel until the audio content is at a volume level such that it
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can still be heard, but is low enough that the speech on MIC 1 can be clearly
heard over the audio content.
29. Trigger your alarm source so that a trigger signal is present on the EMC input
terminals. Verify that the audio from MIC 2, MIC 3, the CD player, and the FM
tuner are all completely muted. Verify that voice on MIC 1 can be clearly heard.
30. Check the device that is connected to the MIX OUT to verify that it is receiving
the audio mix.
Congratulations, your PA system is setup and configured and is ready for use!
INSTALLATION NOTES
If using a 70V or 100V constant voltage speaker array, ensure that the total
wattage does not exceed 80% of the amplifier's RMS capacity, i.e., 48 (18803), 96
(14886), or 192 (18805) watts.
For best results, MIC 1 should have a power switch so that it can be turned off to
prevent accidental broadcast.
You can connect line level devices, such as CD players, DVD players, etc., instead
of microphones, to the MIC 2 LINE and MIC 3 LINE RCA inputs. You may need to
adjust the individual MIC GAIN control to get the desired audio output level.
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FUNCTIONAL BLOCK DIAGRAM
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SPECIFICATIONS
Model
18803
14886
18805
Rated Output Power
60 watts
120 watts
240 watts
Speaker Outputs
Low impedance (4~16 ohms), Constant voltage (70V or 100V)
Inputs
MIC 1: unbalanced 1/4" TRS, 5mV, 600 ohms
MIC 2-3: Unbalanced TRS, balanced XLR, 5mV, 600 ohms
MIC 2-3 LINE: Unbalanced stereo RCA, 775mV, 10 kilohms
AUX 1-2: Unbalanced RCA, 350mV, 10 kilohms
EMC: Unbalanced EMC, 775mV, 10 kilohms
Bass Adjustment
±10dB at 100Hz
Treble Adjustment
±10dB at 10kHz
Frequency Response
50Hz ~ 16kHz
Signal-to-Noise
Ratio
MIC 1-3: 66dB
AUX 1-2: 80dB
THD
< 0.5% at 1kHz, 1/3 rated power
Crosstalk
≤ 50dB
Muting Function
Automatic 0-30dB reduction on all inputs except MIC 1 when
MIC 1 is active
Protection
Short circuit, over-current, overheating
Input Power
100~120 VAC, 50/60Hz
Power Consumption
100 watts
200 watts
400 watts
Dimensions
19.1" x 13.2" x 3.5"(484 x 335 x 88 mm)
Weight
15.7 lbs. (7.1 kg)
20.5 lbs. (9.3 kg)
36.6 lbs. (16.6 kg)
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REGULATORY COMPLIANCE
Notice for FCC
This device complies with Part 15 of the FCC rules. Operation is subject to the following two
conditions: (1) this device may not cause harmful interference, and (2) this device must accept
any interference received, including interference that may cause undesired operation.
Modifying the equipment without Monoprice's authorization may result in the equipment no
longer complying with FCC requirements for Class B digital devices. In that event, your right to
use the equipment may be limited by FCC regulations, and you may be required to correct any
interference to radio or television communications at your own expense.
This equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection
against harmful interference in a residential installation. This equipment generates, uses and can
radiate radio frequency energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communications. However, there is no
guarantee that interference will not occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception, which can be determined by turning
the equipment off and on, the user is encouraged to try to correct the interference by one or
more of the following measures:
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the
receiver is connected.
Consult the dealer or an experienced radio/TV technician for help.
Notice for Industry Canada
This Class B digital apparatus complies with Canadian ICES-003.
Cet appareil numérique de la classe B est conforme à la norme NMB-003 du Canada.
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