MPA SERIES
MIXER-AMPLIFIER
Installation and User Guide
Contents
Safety Information ........................................ 4
Safety Notes regarding Installation ........................4
Conformities .................................................. 4
Safety Considerations and Information ................4
Caution - High Voltages ............................................ 4
Caution - Mains Fuse ................................................4
Caution - Servicing .................................................... 4
General Description ...................................... 5
Schematic Diagram ...................................... 5
Front Panel Description ............................... 6
Rear Panel Description ................................. 6
Music Inputs ................................................... 7
Sensitivity & Gain Control ....................................... 7
Music Source Select ..................................................7
Music Level Control .................................................. 7
Remote Control of Music Source .........................7
Select and Level .......................................................... 7
General Notes ............................................. 11
Multi-zone Applications ..........................................11
EMC Considerations ...............................................11
Earthing ......................................................................11
Ventilation .................................................................. 11
Technical Specications .............................. 12
Location of internal jumpers, etc. .............. 13
Factory Default Jumper Settings ...........................13
Music Equalisation ......................................... 8
Music Priority ................................................ 8
Microphone Inputs ........................................ 8
Gain Control ...............................................................8
Microphone Access Input ......................................... 8
Front Panel Microphone Level Controls ..... 8
Microphone Equalisation .............................. 8
Microphone Priority ...................................... 9
Microphone over music priority ............................9
Mic 1 over Mics 2-4 priority ...................................9
Chime ............................................................. 9
Power Amplier Stage and Outputs............ 9
Line Output .................................................................9
Low impedance operation ....................................... 9
High pass lter ..........................................................10
Music Mute(Fire Alarm Interface) ............. 10
Bose® Equalisation Modules ..................... 10
Installation Instructions ..........................................10
MPA Series User Manual v1.2 3
Safety Information
Safety Notes regarding Installation
• Do not expose the unit to water or moisture.
• Do not expose the unit to naked ames.
• Do not block or restrict any air vent.
• Do not operate the unit in ambient temperatures above
35OC.
• Do not touch any part or terminal carrying the
hazardous live symbol ( ) while power is supplied to
the unit.
• Do not perform any internal adjustments unless you
are qualied to do so and fully understand the hazards
associated with mains-operated equipment.
• The unit has no user-serviceable parts. Refer servicing
to qualied service personnel.
• If the moulded plug is cut off the mains lead for any
reason, the discarded plug is a potential hazard and
should be disposed of in a responsible manner.
For more detailed information refer to the rear of the manual.
Safety Notes
Safety Considerations and Information
The unit must be earthed. Ensure that the mains power
supply provides an effective earth connection using a threewire termination.
When the mains switch is in the off ‘O’ position the live
and neutral conductors of the mains transformer are
disconnected.
Caution - High Voltages
Do not touch any part or terminal carrying the hazardous
live symbol ( ) while power is supplied to the unit.
Terminals to which the hazardous live symbol refers require
installation by a qualied person.
Caution - Mains Fuse
Replace the mains fuse only with the same type and rating as
marked on the rear panel.
The fuse body size is 20mm x 5mm.
Caution - Servicing
The unit contains no user serviceable parts. Refer servicing
to qualied service personnel. Do not perform servicing
unless you are qualied to do so.
Disconnect the power cable from the unit before removing
the top panel and do not make any internal adjustments with
the unit switched on.
Conformities
This product conforms to the following European EMC
Standards:
BS EN 55103-1:1997
BS EN 55103-2:1997
This product has been tested for use in commercial and
light industrial environments. If the unit is used in controlled
EMC environments, the urban outdoors, heavy industrial
environments or close to railways, transmitters, overhead
power lines, etc., the performance of the unit may be
degraded.
The product conforms to the following European electrical
safety standard:
BS EN 60065:2002
The MPA Series was developed and manufactured with high
quality materials and components, which can be recycled
and/or reused.
The WEEE symbol indicates that
electrical and electronic equipment
must be disposed of separately from
normal waste at the end of its
operational lifetime.
Only reassemble the unit using bolts/screws identical to the
original parts.
Please dispose of this product by taking it to your local
collection point or recycling centre.
MPA Series User Manual v1.24
General Description
The Cloud MPA Series is a range of mixer-ampliers with applications in Licensed, Retail, Leisure and similar venues.
Three models are available to suit different output power requirements (60, 120 or 240 watts); otherwise all models have
identical facilities.
The mixer-ampliers have inputs for six stereo line signals and four microphone signals. Front panel controls are provided
for music source selection, music level and microphone levels. All pre-set controls are located on the rear panel with further
conguration jumpers mounted on the main PCB.
A remote level control or combined level control/music source selector can be wired to the unit for installations that require
remote control.
Schematic Diagram
g.1: MPA Series Schematic Diagram
MPA Series User Manual v1.2 5
5
L6
L5
L4
L3
L2
L1
MUSIC
MUTE
MAINS
6
O
POWER
I
7
4
6 6 6 6
4 4 4 488 8 8 8
PEAK
OFF OFF OFF OFF
6
55 5 5 577 7 7 7
4
33 3 3 399 9 9 9
22 2 2 21010 10 10 10
11 1 1 1
OFF
LEVEL LEVEL LEVEL LEVEL
7
g.2: MPA Front Panel
Front Panel Description
1
MIC LEVEL 1 to 4 - level controls for Mic Inputs 1
to 4
2
MUSIC SOURCE – selects active Line Input
(1 to 6)
3
MUSIC LEVEL – adjusts level of selected Line Input
1
2
2
3
4
PEAK – illuminates if Mic or Line signals level are too
1
high
5
MUSIC MUTE – illuminates when external
Emergency Mute is active
6
MAINS – AC power switch with LED
7
Ventilation slots – forced-air cooling air intake
15
9
13
7
5
4
6
g.3: MPA Rear Panel
Rear Panel Description
1
LINE 1 to LINE 6 – stereo line inputs for music
sources
2
GAIN 1 to GAIN 6 – level trims for each line input
3
MUSIC EQ – LF and HF EQ adjustment for music
channel
4
MIC 1 to MIC 4 – balanced mic inputs
5
GAIN 1 to GAIN 4 – level trims for each mic input
6
MIC EQ – LF and HF EQ adjustment for mic channel
7
ACCESS – external paging control input for
Mic 1
8
LOW IMPEDANCE OUTPUT – speaker output
for low-Z connection
3
9
10
12
LINE OUTPUT – for connection of 100 V/
8
11
14
70 V/25 V line distribution system
MUSIC MUTE – Emergency control input for muting
10
music source
REMOTE MUSIC CONTROL – for connection of
11
RL-1 or RSL-6 remote control panels
REMOTE/LOCAL – disables front panel controls
12
when remote control is in use
13
IEC mains input
14
Mains fuse
15
Fan – forced-air cooling air exhaust
MPA Series User Manual v1.26
Music Inputs
The unit has six stereo line inputs; these inputs are suitable
for most music sources such as compact disc players, tape
players, satellite receivers and the like. Each stereo input is
summed internally to mono.
Music Level Control
A front panel mounted music level control is provided.
Remote control of music level is possible by connecting a
remote control plate (either RSL-6 or RL-1), See g.4.
All inputs are unbalanced and use RCA phono sockets. The
input impedance is 47k ohm.
Line 6 input can be congured to have priority over any
other music source, see Music Priority, page 8.
Sensitivity & Gain Control
All six stereo line inputs have a preset gain control on the
rear panel adjacent to the respective input sockets. The gain
control has a range of 20 dB allowing the input sensitivity to
be varied from -12 dBu (200 mV) to +8 dBu (2.0 V).
The preset gain control should be adjusted so that all the
input signals are operating at the same level and that the
front panel level control has an optimum range of control.
Music Source Select
This front panel six position switch is used to select the
desired music signal. Remote control of source selection is
possible with a remote control plate (RSL-6), See g.4.
Remote Control of Music Source
Select and Level
The MPA Series mixer-ampliers are compatible with
standard Cloud remote control plates Types RSL-6 (music
source select and level) and RL-1 (level only).
Either type of plate may be connected at the rear 3-pin
5 mm-pitch screw terminal connector (Remote Music
Control), using the wiring shown in g.4.
Use two-core (RSL-6 or RL-1) or single-core (RL-1 only)
screened cable to connect the remote level plate (max
length 100 metres).
Pressing the button adjacent to the rear panel connector
activates the remote control plate and disables both the
front panel level and source select controls. If an RL-1 is
being used, the internal jumper J4 should be moved from
its default ‘SW’ setting to ‘FR’, to override the disabling of
the front panel source select switch. See g.7 for location of
jumpers.
REMOTE LEVEL CONTROL WIRING
RL-1
123
SINGLE-CORE SCREENED CABLE MAY BE USED
g.4: RL-1 and RSL-6 Wiring
1 2 3
PIN 1: SCREEN (GROUND)
PIN 2: COLD/ANTIPHASE (-)
PIN 3: HOT/PHASE (+)
+
-
BALANCED CONNECTION
REMOTE MUSIC
CONTROL
CONNECTOR
123
MIC INPUTS
SCN
REMOTE SOURCE & LEVEL CONTROL WIRING
123
RSL-6
USE TWO-CORE SCREENED CABLE
1 2 3
SCN
+
UNBALANCED CONNECTION
REMOTE MUSIC
CONTROL
CONNECTOR
123
g.5: Microphone Input Wiring
MPA Series User Manual v1.2 7
Music Equalisation
One set of independent bass and treble controls is provided
for the music signals. These preset controls are located
on the rear panel below the line input sockets. The treble
control has a range of ±10 dB at 10 kHz and the bass
control has a range of ±10 dB at 50 Hz.
Music Priority
A Juke Box, Digital Sound Store or other audio source can
be given automatic priority over all other music inputs by
connecting it to Line 6 input and moving internal jumpers
5A and 5B from the OFF position (factory default) to the
ON. When this mode of operation is selected, the unit
will operate normally until a signal is detected on Line 6,
when the selected source (usually background music) is
muted, allowing the source connected to Line 6 to replace
it. Once the signal on line 6 stops, the selected source will
smoothly restore to its former level. The time taken for the
restoration is set in the factory at 3 seconds, but it may be
set at 6 or 12 seconds with internal jumper J7. (3s is suitable
for announcements, but the longer times may be more
appropriate when a jukebox or similar is the Line 6 source.)
See g.7 for location of jumpers.
Microphone Access Input
Mic input 1 is equipped with an external access control
input; this is a 2-pin 5 mm-pitch screw terminal connector
adjacent to the Mic input 1 connector. The access input
is primarily intended to provide compatibility with paging
microphones and their associated switching arrangements.
By default, the access function is bypassed.
To use the function, it must be enabled by moving internal
jumper J13 from its default ON setting to OFF. See g.7 for
location of jumpers. Once enabled, the microphone input
is muted while the pins of the access connector are opencircuit. When the pins are connected together, Mic input 1
becomes active for use.
The access input can also trigger the following functions:
• Mic 1 Priority over Mics 2-4
Activation of Mic 1 via the access input will give Mic 1
priority over Mics 2, 3 and 4 if internal jumper J8 is set
to ON. See g.7 for location of jumpers. See also Mic 1
over Mics 2-4 priority, page 9.
• Chime
The internal chime generator will be activated if internal
jumper J1 is set to ON. See g.7 for location of jumpers.
See also Chime, page 9.
Microphone Inputs
Four microphone inputs are provided; the microphone pre-
ampliers are an electronically balanced, transformer-less
design congured for optimum low noise performance. The
input impedance is greater than 2 kΩ and is suitable for
microphones in the 200 Ω to 600 Ω range.
Inputs are via 3-pin 3.5 mm-pitch screw terminal connectors
on the rear panel.
Connect microphones as shown in g.5. Note that if using an
unbalanced microphone, pins 1 and 2 should be connected
together.
Phantom power is available on any or all of the mic inputs,
and is activated by setting internal jumpers J9 to J12 (for
mic inputs 1 to 4 respectively) to the ON position. See g.7
for location of jumpers.
Care should be taken to ensure that phantom power is
activated only when the microphone connected to the
input requires external phantom power; damage to the
microphone may result otherwise.
Gain Control
A mic gain control (of the preset type) is provided adjacent
to each input connector.
The gain can be adjusted from 10 dB to 50 dB. A high
overload margin is maintained at all gain settings.
Front Panel Microphone Level
Controls
A separate level control is provided for each mic input and
these provide the user with a convenient means of adjusting
the audio level of the microphones.
The microphone signals are routed directly to the power
stage and are unaffected by the operation of the music level
control.
The gain controls on the rear panel (see Gain Control)
should be set at a level where microphone distortion does
not occur even when the front panel level controls are fully
clockwise.
Microphone Equalisation
The four microphone inputs are summed together and are
routed to the power stage via a xed high pass lter and
an adjustable EQ section. The xed lter attenuates the
signal below 100 Hz, which helps to reduce the effects of
microphone handling noise.
The two preset EQ controls are on the rear panel adjacent
to the mic inputs; the LF and HF controls provide ±10 dB
of adjustment below 100 Hz and above 5 kHz respectively.
After installation, some test announcements should be made,
MPA Series User Manual v1.28
ideally by the people who will normally make them. The Mic
EQ should be adjusted if necessary to maximise voice clarity.
Microphone Priority
MPA Series mixer-ampliers provide two separate
microphone priority functions. One of these enables the
microphones to have priority over music, the other allows
Mic 1 to have priority over the other microphones.
Microphone over music priority
Fully automatic voice operated priority (VOX function) is
available for the microphone signals. This function is enabled
by internal jumper J6 (default setting is ON). When enabled,
the music signal is automatically attenuated by 30 dB when
a microphone signal is detected, allowing the message to be
clearly heard. Normal music operation is restored smoothly
after the announcement ends.
Note that the presence of a signal on any of the four mic
inputs will operate this function.
Mic 1 over Mics 2-4 priority
If internal jumper J8 is set to ON (the default setting is
OFF), Mic inputs 2, 3 and 4 will be muted whenever the
Microphone Access Input is enabled. This ensures that Mic 1
will always have priority over any other microphones in use
when Mic 1 is used for paging.
Note that if jumper J13 is left at its default setting of ON,
Mics 2, 3 and 4 will be permanently disabled by this function,
leaving Mic 1 as the only active microphone input.
Chime
The MPA Series ampliers have an internal pre-
announcement chime generator. The chime is triggered by
the Microphone Access Input, if enabled by jumper J1 being
set to ON. J1’s default setting is OFF.
An internal preset rotary control is provided to adjust the
chime volume; the front panel level controls have no effect
on the chime level. See g.7 for locations of internal controls.
Power Amplier Stage
and Outputs
Line Output
The MPA Series amplier’s output stage incorporates
an output transformer suitable for driving 100 V, 70 V or
25 V line speaker distribution system. The secondary (output
side) of the transformer is permanently wired to the line
output connector (a 4-pin 5 mm-pitch screw terminal type).
A safety cover is tted over the connector, which may be
removed to connect the speaker cable. Replace the cover
after the connection has been made.
The transformer secondary has 3 line outputs: 100 V, 70 V
and 25 V; while these have a common 0 V connection, the
output is fully oating i.e., it is isolated from the rest of the
amplier. The maximum total combined load should not
exceed the rated power for the amplier model (see table
below).
When driving 100/70/25 V line circuits, it is strongly
recommended that the amplier’s 65 Hz high pass lter is
set ON (see High pass lter - page 10).
Low impedance operation
To convert the amplier to low impedance operation, the
primary winding of the toroidal transformer nearer the
rear of the unit should be unplugged from CON8 on the
main pcb (a short pair of heavy red and black wires), and
replaced by the spare plug connected to the rear panel low
impedance output socket (same wire types). Refer to g. 7
(page 13) for the location of this connector. Note that the
100/70/25 V line outputs will no longer be available once
the transformer is unplugged even though the transformer
secondary is still connected to the line output connector.
The low impedance output is available on a 2-pin 5 mm-pitch
screw terminal connector on the rear panel. Note that one
of the output pins is connected internally to 0 V.
The MPA Series ampliers are able to deliver their rated
power into a 4 ohm load, as follows:
Model Rated Power
MPA60
MPA120
MPA240
60 watts
120 watts
240 watts
The maximum output power will be reduced with higher
load impedances. When using multiple low-impedance
loudspeakers (normally 8 ohms) with a single amplier, series
and parallel wiring should be employed to produce a total
load impedance of not less than 4 ohms.
MPA Series User Manual v1.2 9
High pass lter
A high pass lter is provided to protect speakers,
transformers etc. from the effects of low frequency signals.
The lter is enabled by the internal jumper J2 (see g.7). The
lter reduces the output level of frequencies below 65 Hz,
and ideally should be used if the line output transformer is
in circuit.
Music Mute
(Fire Alarm Interface)
Bose® Equalisation Modules
MPA Series ampliers are compatible with single channel
Bose® Series II equalisation modules. EQ modules are
available to suit the following Bose® loudspeakers:
• Panaray MA12
• Panaray 402-II, 502B and 502BEX
• Panaray LT Series:
Models 3302, 4402, 9402 and 9702.
Modules to suit other models are available – please enquire.
In some installations (such as licensed premises or retail
outlets within a shopping mall), there may be a local
authority or re service requirement to mute the music
signals from a re alarm control panel when an alarm
condition arises. The MPA Series ampliers include a
facility to mute the music signals only (i.e., mic inputs are
still active), via the Music Mute input. This is a 2-pin 5 mmpitch screw terminal connector on the rear panel, and the
contacts are fully isolated.
Activation of the Music Mute is often via a relay mounted
close to the MPA Series amplier, powered by the re alarm
control panel. Other arrangements may exist depending
on the design of the re control system and the re alarm
installation company should be consulted when making the
connection. The MPA Series ampliers will mute on either a
contact closure at the Music Mute input (NO) or an opencircuit (NC). Selection of NO or NC operation is made with
internal jumper J14. NO is the factory default. See g.6.
Installation Instructions
Refer to the pcb layout diagram (see g.7) for the location
of the Bose EQ module connector and its associated bypass
jumper J3.
To install an EQ module, proceed as follows:
1. Switch off the power and isolate the unit from the
mains.
2. Remove the top panel.
3. Remove jumper J3 from the main pcb.
4. Plug the Bose® equalisation module onto its connector;
note that the connector has two notches on one
side which engage with lugs on the module’s mating
connector to ensure correct orientation.
5. Replace the top panel.
RELAY
NORMALLY OPEN (NO)
CONNECTION
g.6: Remote Music Mute
MPA Series User Manual v1.210
REMOTE MUSIC MUTE TERMINATIONS
MUSIC MUTE
INPUT
1 2
RELAY
NORMALLY CLOSED (NC)
MUSIC MUTE
INPUT
1 2
CONNECTION
General Notes
Multi-zone Applications
Where the sound system specication calls for separate
control in several zones, MPA Series ampliers can be used
in multiples.
Signal sources can be connected to several inputs as
required, but care must be taken to ensure the output stage
of the signal source is capable of driving the resulting lower
input impedance.
The impedance of the line inputs (music inputs) is 47k ohms
and it is reasonable to assume that most op-amp based
signal sources are able to drive a 10k ohm load, allowing up
to ve ampliers to be paralleled.
Earthing
When several mains powered units are connected together
via their signal cables, there is a risk of one or more earth
loops which may cause an audible hum on the system even
with the gain controls set to minimum.
The 0 V rail of an MPA Series amplier is directly coupled to
the chassis ground. No interconnection problems should be
encountered, but if there is any hum or other extraneous
noise when source equipment is connected, the situation can
generally be remedied by observing the following guidelines:
• Always connect sources using balanced connections
wherever possible, with the cable screen only connected
at the receiving end (amplier input).
The input impedance of the mic inputs is 2.4k ohms, making
them suitable for microphones with a nominal impedance
of 600 ohms or less. A single 600 ohm microphone
could therefore typically be connected to four paralleled
mic inputs. If this guideline gure cannot be adhered to,
the use of suitable mic or line distribution ampliers is
recommended.
To avoid any problems associated with differences in
mains supply earthing, we recommend that all MPA Series
ampliers used in a multi-zone application should be co-
located and connected to a common mains supply.
Note that when using multiple MPA Series ampliers in a
19” rack, suitable ventilation arrangements must be made to
ensure that lower ampliers do not cause those above to
overheat (see Ventilation for further information).
EMC Considerations
MPA Series ampliers fully conform to the relevant
electromagnetic compatibility (EMC) standards and are
technically well behaved. You should experience no problems
interfacing units to other items of equipment and under
normal circumstances, no special precautions need to be
taken.
If the unit is to be used in close proximity to potential
sources of HF disturbance such as high power
communication transmitters, radar stations and the like, it is
suggested that input signal leads be kept as short as possible.
Always use balanced interconnections wherever possible. If
the MPA Series amplier is mounted in a 19” rack, do not
locate the unit in close proximity to a powerful amplier of
any kind, which may radiate a strong magnetic eld from the
power transformer.
• Use audio isolating transformers (readily available from
trade suppliers) at the inputs if necessary. These will
ensure that the amplier is electrically isolated from the
source equipment.
• The signal source units should be located as close as
possible to the ampliers and the metal housing of
the various units should not be electrically connected
together through the equipment rack. If this is a
problem, rack isolating kits are available from specialist
hardware suppliers. If the problem persists, try to
connect all interconnected units, including power
ampliers to a common power source to ensure a
common ground is provided.
Ventilation
MPA Series ampliers are force cooled by a thermostatically-
controlled fan. The fan is operative at all times, remaining
at low speed at internal temperatures below 50 ºC, then
increasing in speed above this temperature to a maximum
speed at 70 ºC.
Always allow adequate space around the amplier(s) to
allow a free ow of air through the unit(s). In 19” rack
applications we recommend leaving 1U of rack space above
and below each unit. Plain 1U blank panels, not slotted
ventilation panels should be used, as the latter reduce the
effect of forced-air cooling.
The direction of airow in MPA Series ampliers is from
front-to-rear; it is recommended not to mix the ampliers
with other equipment employing forced-air cooling which
acts in the opposite direction within the same rack.
In free standing applications we recommend tting the
feet supplied and placing the unit on a at surface and
leaving the ventilation slots on top of the unit free from any
obstructions.
MPA Series User Manual v1.2 11
Technical Specications
Line Inputs
Frequency response
Distortion
Sensitivity
Input Gain control
Input impedance
Headroom
Noise
Equalisation
Low-Z output +0 dB/-1 dB from 20 Hz – 20 kHz (65 Hz lter switched out)
High voltage outputs +0 dB/-2 dB from 20 Hz – 20 kHz (65 Hz lter switched out)
Low-Z output <0.03% @ 1 kHz, 1 dB below full power (80 kHz bandwidth)
High voltage outputs <0.04% @ 1 kHz, 1 dB below full power (80 kHz bandwidth)
195 mV (-12 dBu) to 2.0 V (+8 dBu)
20 dB range
47k ohms
>20 dB
-90 dB 22 Hz –22 kHz, at speaker output, relative to full power
HF: ±10 dB/10 kHz LF: ±10 dB/50 Hz
Microphone Inputs
Frequency response
Distortion <0.03% @ 1 kHz, 1 dB below full power (80 kHz bandwidth)
Gain range 40 dB range
Input Impedance >2k ohms (balanced)
Phantom Power 15 v, switchable per-input by jumpers
Headroom >20 dB
Noise -127 dB EIN 22 Hz-22 kHz (150 ohms)
Equalisation
Low-Z output -3 dB @ 100 Hz (3rd. order lter); -1 dB @20 kHz
High voltage output -3 dB @ 100 Hz (3rd. order lter); -2 dB @20 kHz
HF: ±10 dB/5 kHz LF: ±10 dB/100 Hz
Outputs
Output Power* (any out-
put, 1kHz continuous sine
wave @ <0.07% THD+N)
Protection Fixed level signal limiter max gain reduction of 20 dB, DC protection, IV limiting & short
Cooling Forced-air, front-to-rear airow, thermostatically controlled
* see also Low impedance operation, page 9.
MPA60 60 watts
MPA120 120 watts
MPA240 240 watts
circuit protection, switch-on delay
General Specications
Power input 230 V, 115 V, 100 V versions available
MPA60 230 V T1A H
115/100 V T2A H
Fuse rating
Fuse type All models 20 mm x 5 mm
Dimensions (mm) 482.6 wide x 88 high (2U) x 300 deep (+ connectors & knobs)
Net weight (kg)
MPA120 230 V T2A H
115/100 V T4A H
MPA240 230 V T4A H
115/100 V T8A H
MPA60 9.0
MPA120 10.5
MPA240 21.6
MPA Series User Manual v1.212
Location of internal jumpers, etc.
J1
BOSE EQ
CARD SOCKET
J2
J3
MPA SERIES: MAIN PCB.
TOP VIEW. ONLY PRIMARY
COMPONENTS SHOWN.
J4
J6
J7
J8
J9
J13
(under sub-board)
g.7: Internal jumpers
J10
J11
(below ribbon cable)
CHIME
VOLUME CONTROL
J5A &
J5B
J12
FAN
REAR OF AMPLIFIER
CON8
NOT TO SCALE
J14
Factory Default Jumper Settings
Jumper Function Default Setting
J1
J2
J3
J4
J5 (A & B)
J6
J7
J8
J9
J10
J11
J12
J13
J14 Music Mute NO or NC NO
Mic 1 access triggers chime
65 Hz high pass lter frequency
EQ card socket bypass
Front panel source select switch disable
Line input 6 priority
Mic over music priority (VOX function)
Line 6 priority release time 3, 6 or 12 seconds
Mic 1 priority over Mics 2, 3 & 4
Mic 1 phantom power
Mic 2 phantom power
Mic 3 phantom power
Mic 4 phantom power
Mic 1 Access Input bypass
OFF
ON
ON
SW
OFF
ON
3S
OFF
OFF
OFF
OFF
OFF
ON
MPA Series User Manual v1.2 13
Bose® is a registered trademark of The Bose Corporation.
In the interest of continuing improvements Cloud Electronics Limited reserves
the right to alter specications without prior notice.
MPA Series User Manual v1.214
Cloud Electronics Limited
140 Staniforth Road
Shefeld S9 3HF
England
Tel: +44 (0)114 244 7051
Fax: +44 (0)114 242 5462
email: info@cloud.co.uk
web: www.cloud.co.uk
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