Cloud | MPA SERIES | User guide | Cloud MPA SERIES User guide

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
General Notes.............................................. 11
Multi-zone Applications...........................................11
EMC Considerations................................................11
Earthing.......................................................................11
Ventilation...................................................................11
Technical Specifications............................... 12
Location of internal jumpers, etc................ 13
Factory Default Jumper Settings............................13
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
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 Amplifier Stage and Outputs............ 9
Low impedance operation........................................ 9
Line Output.................................................................. 9
High pass filter...........................................................10
Music Mute(Fire Alarm Interface).............. 10
Bose® Equalisation Modules ...................... 10
Installation Instructions...........................................10
MPA Series User Manual v1.1
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Safety Information
Safety Considerations and Information
Safety Notes regarding Installation
The unit must be earthed. Ensure that the mains power
supply provides an effective earth connection using a threewire termination.
•• Do not expose the unit to water or moisture.
•• Do not expose the unit to naked flames.
•• 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 (
the unit.
) while power is supplied to
•• Do not perform any internal adjustments unless you
are qualified to do so and fully understand the hazards
associated with mains-operated equipment.
•• The unit has no user-serviceable parts. Refer servicing
to qualified 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
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 qualified 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 qualified service personnel. Do not perform servicing
unless you are qualified 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.
Please dispose of this product by taking it to your local
collection point or recycling centre.
4
MPA Series User Manual v1.1
Only reassemble the unit using bolts/screws identical to the
original parts.
General Description
The Cloud MPA Series is a range of mixer-amplifiers 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-amplifiers 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
configuration 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
fig.1: MPA Series Schematic Diagram
MPA Series User Manual v1.1
5
5
6
7
7
4
MAINS
O
I
5
L6
L5
L2
7
9
2
L1
fig.2: MPA Front Panel
5
6
4
10
1
7
6
5
8
9 3
2
PEAK
OFF
7
8
3
10
1
MUSIC
MUTE
6
5
4
8
3
L3
POWER
6
4
L4
7
4
9 3
2
OFF
LEVEL
10
1
5
8
6
4
2
10
1
OFF
LEVEL
9
2
10
1
OFF
LEVEL
7
8
9 3
OFF
LEVEL
1
2
3
1
MIC LEVEL 1 to 4 - level controls for Mic Inputs 1
to 4
4
PEAK – illuminates if Mic or Line signals level are too
high
2
MUSIC SOURCE – selects active Line Input
(1 to 6)
5
MUSIC MUTE – illuminates when external
Emergency Mute is active
3
MUSIC LEVEL – adjusts level of selected Line Input
6
MAINS – AC power switch with LED
7
Ventilation slots – forced-air cooling air intake
Front Panel Description
1
2
15
6
7
9
3
10
12
11
13
8
14
5
4
fig.3: MPA Rear Panel
Rear Panel Description
6
1
LINE 1 to LINE 6 – stereo line inputs for music
sources
9
LINE OUTPUT – for connection of 100 V/
70 V/25 V line distribution system
2
GAIN 1 to GAIN 6 – level trims for each line input
10
3
MUSIC EQ – LF and HF EQ adjustment for music
channel
MUSIC MUTE – Emergency control input for muting
music source
11
REMOTE MUSIC CONTROL – for connection of
RL-1 or RSL-6 remote control panels
12
REMOTE/LOCAL – disables front panel controls
when remote control is in use
13
IEC mains input
14
Mains fuse
15
Fan – forced-air cooling air exhaust
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
MPA Series User Manual v1.1
Music Inputs
Music Level Control
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.
All inputs are unbalanced and use RCA phono sockets. The
input impedance is 47k ohm.
Line 6 input can be configured 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 fig.4.
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 fig.4.
Remote Control of Music Source
Select and Level
The MPA Series mixer-amplifiers 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 fig.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 fig.7 for location of
jumpers.
REMOTE LEVEL CONTROL WIRING
REMOTE SOURCE & LEVEL CONTROL WIRING
REMOTE MUSIC
CONTROL
CONNECTOR
RL-1
1
2
REMOTE MUSIC
CONTROL
CONNECTOR
3
RSL-6
1
2
1
3
2
1
3
SINGLE-CORE SCREENED CABLE MAY BE USED
2
3
USE TWO-CORE SCREENED CABLE
fig.4: RL-1 and RSL-6 Wiring
MIC INPUTS
1
2
PIN 1: SCREEN (GROUND)
PIN 2: COLD/ANTIPHASE (-)
PIN 3: HOT/PHASE (+)
3
+
1
2
3
SCN
SCN
+
BALANCED CONNECTION
UNBALANCED CONNECTION
fig.5: Microphone Input Wiring
MPA Series User Manual v1.1
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Music Equalisation
Microphone Access Input
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.
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.
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 fig.7 for location of jumpers.
Microphone Inputs
Four microphone inputs are provided; the microphone preamplifiers are an electronically balanced, transformer-less
design configured 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 fig.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 fig.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.
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MPA Series User Manual v1.1
To use the function, it must be enabled by moving internal
jumper J13 from its default ON setting to OFF. See fig.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 fig.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 fig.7 for location of jumpers.
See also Chime, page 9.
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 fixed high pass filter and
an adjustable EQ section. The fixed filter 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,
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-amplifiers 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 amplifiers have an internal preannouncement 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 fig.7 for locations of internal controls.
Power Amplifier Stage and Outputs
Low impedance operation
The MPA Series amplifiers are able to deliver their rated
power into a 4 ohm load, as follows:
MPA60
Model
Rated Power
60 watts
MPA120
120 watts
MPA240
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 amplifier, series and/or parallel wiring
should be employed to produce a total load impedance of
not less than 4 ohms.
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.
Line Output
MPA Series amplifiers are fitted as standard with an output
transformer that can be enabled by moving an internal
connector. The transformer should be placed in circuit if the
amplifier is to be used with a 100 V, 70 V or 25 V line speaker
distribution system.
To convert the amplifier to high-voltage line operation, the
low impedance output socket 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
toroidal transformer nearer the rear of the unit (same wire
types).
Note that the low-impedance output will no longer be
available once the transformer is plugged in. The secondary
(output side) of the transformer is permanently wired to the
line output connector (a 4-pin 5 mm-pitch screw terminal
type), thus the high-voltage output will be active once the
internal connector change has been made. A safety cover is
fitted 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; whilst these have a common 0 V connection, the
output is fully floating i.e. it is isolated from the rest of the
amplifier. When the transformer is in use the maximum total
combined load should not exceed the rated power for the
amplifier model (see table above).
MPA Series User Manual v1.1
9
When this transformer is in circuit it is strongly
recommended that the amplifier’s 65 Hz high pass filter is
set ON (see section below: High pass filter).
High pass filter
A high pass filter is provided to protect speakers,
transformers etc. from the effects of low frequency signals.
The filter is enabled by the internal jumper J2 (see fig.7). The
filter reduces the output level of frequencies below 65 Hz,
and ideally should be used if the line output transformer is
in circuit.
Bose® Equalisation Modules
MPA Series amplifiers 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.
Installation Instructions
Music Mute (Fire Alarm Interface)
Refer to the pcb layout diagram (see fig.7) for the location
of the Bose EQ module connector and its associated bypass
jumper J3.
In some installations (such as licensed premises or retail
outlets within a shopping mall), there may be a local
authority or fire service requirement to mute the music
signals from a fire alarm control panel when an alarm
condition arises. The MPA Series amplifiers 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 amplifier, powered by the fire alarm
control panel. Other arrangements may exist depending
on the design of the fire control system and the fire alarm
installation company should be consulted when making the
connection. The MPA Series amplifiers 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 fig.6.
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.
REMOTE MUSIC MUTE TERMINATIONS
MUSIC MUTE
INPUT
1
fig.6: Remote Music Mute
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MPA Series User Manual v1.1
2
1
RELAY
RELAY
NORMALLY OPEN (NO)
CONNECTION
MUSIC MUTE
INPUT
NORMALLY CLOSED (NC)
CONNECTION
2
General Notes
Earthing
Multi-zone Applications
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.
Where the sound system specification calls for separate
control in several zones, MPA Series amplifiers 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 five amplifiers to be paralleled.
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 figure cannot be adhered to,
the use of suitable mic or line distribution amplifiers is
recommended.
To avoid any problems associated with differences in
mains supply earthing, we recommend that all MPA Series
amplifiers used in a multi-zone application should be colocated and connected to a common mains supply.
Note that when using multiple MPA Series amplifiers in a
19” rack, suitable ventilation arrangements must be made to
ensure that lower amplifiers do not cause those above to
overheat (see Ventilation for further information).
EMC Considerations
MPA Series amplifiers 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 amplifier is mounted in a 19” rack, do not
locate the unit in close proximity to a powerful amplifier of
any kind, which may radiate a strong magnetic field from the
power transformer.
The 0 V rail of an MPA Series amplifier 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 (amplifier input).
•
Use audio isolating transformers (readily available from
trade suppliers) at the inputs if necessary. These will
ensure that the amplifier is electrically isolated from the
source equipment.
•
The signal source units should be located as close as
possible to the amplifiers 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
amplifiers to a common power source to ensure a
common ground is provided.
Ventilation
MPA Series amplifiers are force cooled by a thermostaticallycontrolled 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 amplifier(s) to
allow a free flow 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 airflow in MPA Series amplifiers is from
front-to-rear; it is recommended not to mix the amplifiers
with other equipment employing forced-air cooling which
acts in the opposite direction within the same rack.
In free standing applications we recommend fitting the
feet supplied and placing the unit on a flat surface and
leaving the ventilation slots on top of the unit free from any
obstructions.
MPA Series User Manual v1.1
11
Technical Specifications
Line Inputs
Frequency response
Low-Z output
High voltage outputs
+0 dB/-1 dB from 20 Hz – 20 kHz (65 Hz filter switched out)
+0 dB/-2 dB from 20 Hz – 20 kHz (65 Hz filter switched out)
Distortion
Low-Z output
High voltage outputs
<0.03% @ 1 kHz, 1 dB below full power (80 kHz bandwidth)
<0.04% @ 1 kHz, 1 dB below full power (80 kHz bandwidth)
Sensitivity
195 mV (-12 dBu) to 2.0 V (+8 dBu)
Input Gain control
20 dB range
Input impedance
47k ohms
Headroom
>20 dB
Noise
-90 dB 22 Hz –22 kHz, at speaker output, relative to full power
Equalisation
HF: ±10 dB/10 kHz
LF: ±10 dB/50 Hz
Microphone Inputs
Frequency response
Distortion
Gain range
Input Impedance
Phantom Power
Headroom
Noise
Equalisation
Low-Z output
-3 dB @ 100 Hz (3rd. order filter); -1 dB @20 kHz
High voltage output
-3 dB @ 100 Hz (3rd. order filter); -2 dB @20 kHz
<0.03% @ 1 kHz, 1 dB below full power (80 kHz bandwidth)
40 dB range
>2k ohms (balanced)
15 v, switchable per-input by jumpers
>20 dB
-127 dB EIN 22 Hz-22 kHz (150 ohms)
HF: ±10 dB/5 kHz
LF: ±10 dB/100 Hz
Outputs
Output Power* (any output, 1kHz continuous sine
wave @ <0.07% THD+N)
Protection
Cooling
MPA60
MPA120
60 watts
120 watts
MPA240
240 watts
Fixed level signal limiter max gain reduction of 20 dB, DC protection, IV limiting & short
circuit protection, switch-on delay
Forced-air, front-to-rear airflow, thermostatically controlled
* see also Low impedance operation, page 9.
General Specifications
Power input
Fuse rating
Fuse type
Dimensions (mm)
Net weight (kg)
12
230 V, 115 V, 100 V versions available
MPA60
230 V
T1A H
115/100 V
T2A H
MPA120
230 V
T2A H
115/100 V
T4A H
MPA240
230 V
T4A H
115/100 V
T6.3A H
All models
20 mm x 5 mm
482.6 wide x 88 high (2U) x 300 deep (+ connectors & knobs)
MPA60
9.0
MPA120
10.5
MPA240
12.6
MPA Series User Manual v1.1
Location of internal jumpers, etc.
J1
J2
MPA SERIES: MAIN PCB.
TOP VIEW. ONLY PRIMARY
COMPONENTS SHOWN.
J3
BOSE EQ
CARD SOCKET
J4
CHIME
VOLUME CONTROL
J6
J7
CON8
J8
FAN
J9
J10
J13
(under sub-board)
J5A &
J5B
NOT TO SCALE
REAR OF AMPLIFIER
J12
J11
(below ribbon cable)
J14
fig.7: Internal jumpers
Factory Default Jumper Settings
Jumper
Function
Default Setting
J1
Mic 1 access triggers chime
OFF
J2
65 Hz high pass filter frequency
ON
J3
EQ card socket bypass
ON
J4
Front panel source select switch disable
SW
Line input 6 priority
OFF
J6
Mic over music priority (VOX function)
ON
J7
Line 6 priority release time 3, 6 or 12 seconds
3s
J8
Mic 1 priority over Mics 2, 3 & 4
OFF
J9
Mic 1 phantom power
OFF
J10
Mic 2 phantom power
OFF
J11
Mic 3 phantom power
OFF
J12
Mic 4 phantom power
OFF
J13
Mic 1 Access Input bypass
ON
J14
Music Mute NO or NC
NO
J5 (A & B)
MPA Series User Manual v1.1
13
Bose® is a registered trademark of The Bose Corporation.
In the interest of continuing improvements Cloud Electronics Limited reserves
the right to alter specifications without prior notice.
14
MPA Series User Manual v1.1
Cloud Electronics Limited
140 Staniforth Road
Sheffield 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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