OPERATING INSTRUCTIONS
700 SERIES AMPLIFIERS
A-706, A-712, A-724
TABLE OF CONTENTS
1. IMPORTANT SAFETY INSTRUCTIONS ........................................................................................ 2
2. SAFETY PRECAUTIONS ............................................................................................................... 2
3. GENERAL DESCRIPTION ............................................................................................................. 4
4. FEATURES ..................................................................................................................................... 4
5. NOMENCLATURE AND FUNCTIONS
Front ................................................................................................................................................ 4
Rear ................................................................................................................................................ 5
6. CONNECTIONS
6.1. Speaker Connections ............................................................................................................... 6
6.2. Remote Volume Control Connection ........................................................................................ 6
6.3. Remote Power ON/OFF Control Connection ........................................................................... 7
6.4. Mute Control Connection ......................................................................................................... 7
6.5. External Equipment Connection to the PRE AMP OUT and PWR AMP IN Terminals ............ 7
7. INSTALLATION .............................................................................................................................. 7
8. RACK MOUNTING ......................................................................................................................... 8
9. CONTROL SETTINGS ................................................................................................................... 8
10. DIMENSIONAL DIAGRAM ............................................................................................................. 8
11. BLOCK DIAGRAM ......................................................................................................................... 9
12. SPECIFICATIONS ........................................................................................................................ 10
Accessories ................................................................................................................................... 10
Optional products .......................................................................................................................... 10
Thank you for purchasing TOA's 700 Series Amplifiers.
Please carefully follow the instructions in this manual to ensure long, trouble-free use of your equipment.
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surface. Doing so may result in the unit falling
down, causing personal injury and/or property
damage.
cord itself. Operating the unit with a damaged
power supply cord may cause a fire or electric
shock.
When the Unit is in Use
• When moving the unit, be sure to remove its power
supply cord from the wall outlet. Moving the unit
with the power cord connected to the outlet may
cause damage to the power cord, resulting in fire or
electric shock. When removing the power cord, be
sure to hold its plug to pull.
• Should the following irregularity be found during
use, immediately switch off the power, disconnect
the power supply plug from the AC outlet and
contact your nearest TOA dealer. Make no further
attempt to operate the unit in this condition as this
may cause fire or electric shock.
· If you detect smoke or a strange smell coming
from the unit.
· If water or any metallic object gets into the unit
· If the unit falls, or the unit case breaks
· If the power supply cord is damaged (exposure of
the core, disconnection, etc.)
• Avoid installing the unit in humid or dusty locations,
in locations exposed to the direct sunlight, near the
heaters, or in locations generating sooty smoke or
steam as doing otherwise may result in fire or
electric shock.
When the Unit is in Use
· If it is malfunctioning (no tone sounds.)
• Do not place heavy objects on the unit as this may
cause it to fall or break which may result in
personal injury and/or property damage. In
addition, the object itself may fall off and cause
injury and/or damage.
• To prevent a fire or electric shock, never open nor
remove the unit case as there are high voltage
components inside the unit. Refer all servicing to
your nearest TOA dealer.
• No objects filled with liquids, such as vases, shall
be placed on the unit. If they accidentally spill into
the unit, this may cause a fire or electric shock.
• Make sure that the volume control is set to
minimum position before power is switched on.
Loud noise produced at high volume when power is
switched on can impair hearing.
• Do not insert nor drop metallic objects or
flammable materials in the ventilation slots of the
unit's cover, as this may result in fire or electric
shock.
• Do not operate the unit for an extended period of
time with the sound distorting. This is an indication
of a malfunction, which in turn can cause heat to
generate and result in a fire.
• Contact your TOA dealer as to the cleaning. If dust
is allowed to accumulate in the unit over a long
period of time, a fire or damage to the unit may
result.
CAUTION
Indicates a potentially hazardous situation which,
if mishandled, could result in moderate or minor
personal injury, and/or property damage.
• If dust accumulates on the power supply plug or in
the wall AC outlet, a fire may result. Clean it
periodically. In addition, insert the plug in the wall
outlet securely.
When Installing the Unit
• Never plug in nor remove the power supply plug
with wet hands, as doing so may cause electric
shock.
• Switch off the power, and unplug the power supply
plug from the AC outlet for safety purposes when
cleaning or leaving the unit unused for 10 days or
more. Doing otherwise may cause a fire or electric
shock.
• When unplugging the power supply cord, be sure
to grasp the power supply plug; never pull on the
An all-pole mains switch with a contact separation of at least 3 mm in each pole shall be incorporated in
the electrical installation of the building.
ATTENTION
L'appareil ne doit pas être exposé aux éclaboussures ou écoulements et tous objets remplis de liquide, tels
que vases, ne doivent pas être sur l’appareil.
3
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3. GENERAL DESCRIPTION
Equipped with 6 LINE/MIC selectable inputs, 2 LINE inputs and 1 MODULE input, the A-706, A-712, and A-
724 PA amplifiers are designed to suit PA system applications such as announcements, BGM and
broadcasting in churches, large rooms and factories.
4. FEATURES
• Power output of 60 W (A-706), 120 W (A-712), and 240 W (A-724).
• Mute Receive function assignable to all inputs, and Mute Send function assignable to Inputs 1 – 3 and Mute
input.
• An equalizer or other signal processor connectable between PWR AMP IN and PRE AMP OUT terminals to
make fine adjustment of sound.
• Tone controls (bass and treble).
• Output level meter.
• Master volume control for adjusting overall input signal level.
• Microphone gain trims for adjusting MIC level on Inputs 1 – 6.
5. NOMENCLATURE AND FUNCTIONS
[Front]
3
4
5
1 2
6
7
8
This figure represents the A-724.
1. Power switch [POWER]
6. Bass control [BASS]
Press to turn ON the power.
Press again to turn the power OFF.
Adjusts bass response. Turn clockwise to increase
bass output, and counterclockwise to decrease it.
The center position provides flat characteristics.
2. Power indicator
Lights green when the power is switched on.
7. Treble control [TREBLE]
Adjusts treble response. Turn clockwise to
increase treble output, and counterclockwise to
decrease it. The center position provides flat
characteristics.
3. Input 1 – 8 volume controls [INPUT 1 – 8]
Adjust the corresponding input signal levels. Turn
each control clockwise to increase and
counterclockwise to decrease the level.
8. Module input volume control [MODULE]
Adjusts the signal level of the module input on the
rear panel. Turn the control clockwise to increase
and counterclockwise to decrease the level.
4. Master volume control [MASTER]
Adjusts the overall signal level. Turn the control
clockwise to increase and counterclockwise to
decrease the level.
5. LED level meter
Indicates an output level.
4
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[Rear]
9
10
11 12
13
14 15 16
17
19
20 21
22
18
This figure represents the A-724.
9. AC inlet
Note
Connect the supplied power cord.
Avoid assigning both functions to the same input.
(1) Mute Receive assignment switches
[MUTE RECEIVE (INPUT CH)]
10. Remote control connector
Removable terminal block.
Allow all inputs (INPUT 1 – 8 and Module) to be
assigned to Mute Receive function.
(1) Remote volume control terminals
[REMOTE VOLUME]
(2) Mute Send assignment switches
[MUTE SEND (INPUT CH)]
Connecting a 10 kΩ linear taper volume control
across these terminals will allow remote control
of preamplifier output and speaker output levels.
Allow the inputs 1 – 3 and Module input to be
assigned to Mute Send function.
(2) Power remote control terminals
[POWER REMOTE]
14. Function switches
Allows remote control of the unit's power
ON/OFF.
(1) Phantom power ON/OFF switch
[PHANTOM ON, OFF]
No-voltage make contact input.
Turns on or off the phantom power for the
corresponding input. This switch is valid only
when the LINE/MIC selector switch is set to the
MIC position.
(3) Mute control terminals [MUTE CONTROL]
Shorting these terminals mutes the Mute
Receive inputs (the inputs set to be muted).
The mute control works regardless of whether or
not there is a signal to a Mute Send input (the
input set to activate muting).
(2) LINE/MIC selector switch [LINE, MIC]
Selects the input sensitivity of LINE or MIC as
follows:
LINE: –10 dB
11. Mute sensitivity control [MUTE SENSE]
Adjusts the threshold level in a range of 36 dB
for the Mute Send inputs to activate the mute
function. Turn clockwise to increase the
threshold level (lower sensitivity), and
counterclockwise to decrease the level (higher
sensitivity).
MIC: –70 to –50 dB, adjustable with the
Microphone gain trimmer (15).
15. Microphone gain trims [MIC TRIM]
Adjust the microphone input gain for the inputs
set to MIC.
16. Input 1 – 6 connectors [INPUT 1 – 6]
–10 dB (LINE) or –70 to –50 dB (MIC)
selectable, 600 Ω, balanced, removable terminal
blocks.
12. Preamplifier output jack [PRE AMP OUT]
0 dB, 600 Ω, unbalanced RCA jack. Outputs all
input signals. Connects to a signal processor
such as a limiter or equalizer. (Refer to p. 7.)
Either LINE or MIC level can be selected by the
Function switch (14).
13. Mute assignment switches
When MIC level is selected, the input sensitivity
can be adjusted from –70 to –50 dB with the
Microphone gain trim (15).
The inputs 2 and 3, which are electronically
balanced, can be converted into transformer-
balanced type by using optional transformers IT-
455.
[MUTE ASSIGNMENT]
Assign the individual inputs to Mute Receive
(inputs to be muted) or Mute Send (inputs to
activate muting) function. When a signal enters a
Mute Send input, Mute Receive inputs are all
muted.
5
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17. Module input slot
21. Power amplifier input jack [PWR AMP IN]
0 dB, 600 Ω, unbalanced RCA jack. Accepts
output signals from the signal processor
connected to the Preamplifier output jack (12).
(Refer to p. 7.)
Accepts TOA's 900 series module.
18. Functional ground terminal
Hum noise may be generated when external
equipment is connected to the unit. Connecting
this terminal to the functional ground terminal of
the external equipment may reduce the hum
noise.
Inserting an RCA plug disconnects the internal
power amplifier section from the preamplifier
section.
22. Input 7 and 8 jacks [INPUT 7, 8]
Note: This terminal is not for protective earth.
–10 dB, 10 kΩ, unbalanced RCA jacks. Accept
output signals from external equipment.
19. Speaker output terminals [SP OUT]
4 Ω, 25 V and 70 V outputs, removable terminal
block. Connects to speakers.
20. Recording output jacks [REC OUT]
0 dB, 600 Ω, unbalanced RCA jacks. Output all
input signals before they enter the master
volume control. Connect a cassette deck, etc.
when recording the broadcast contents.
6. CONNECTIONS
6.1. Speaker Connections
COM 4Ω 25 V 70 V
COM 4Ω 25 V 70 V
COM 4Ω 25 V 70 V
25 V LINE
70 V LINE
Total impedance
10 Ω (A-706)
5.2 Ω (A-712)
2.6 Ω (A-724)
Total impedance
83 Ω (A-706)
42 Ω (A-712)
21 Ω (A-724)
4 – 16 Ω
25 V Line
70 V Line
Notes
• Do not use both the 4 Ω, 25 V and 70 V terminals at the same time.
• Impedances indicated in the figures represent the total speaker system (load) impedances.
6.2. Remote Volume Control Connection
The external volume control can remotely adjust the
signal level at post-master volume control.
When performing the remote volume control, adjust
MUTE
CONTROL
the master volume control in advance noting that its
setting limits the maximum signal level adjustable
with the volume control. Be sure to avoid turning fully
Volume control
10 kΩ (linear-taper)
down the master volume control.
REMOTE
POWER
VOLUME REMOTE
6
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6.3. Remote Power ON/OFF Control Connection
To perform this control, be sure to turn the power switch OFF.
Shorting the power remote control terminals turns the power on, and
opening them turns the power off.
With the power switch ON, the power on/off cannot be remotely
controlled.
MUTE
CONTROL
REMOTE
POWER
VOLUME REMOTE
6.4. Mute Control Connection
MUTE
CONTROL
Shorting the mute control terminals mutes the Mute Receive inputs (the
inputs set to be muted).
Note
The mute control works regardless of whether or not there is a signal to
a Mute Send input (the input set to activate muting).
REMOTE
VOLUME REMOTE
POWER
6.5. External Equipment Connection to the PRE AMP OUT and PWR AMP IN Terminals
By connecting a signal processor such as an
equalizer or limiter between the preamplifier section
(PRE AMP OUT) and the power amplifier section
PRE AMP OUT
A-700 series
(PWR AMP IN) of the A-700 series, signals can be
PWR AMP IN
tailored for desired sound output.
Note
Equalizer, limiter, etc.
Inserting an RCA plug into the PWR AMP IN
OUT IN
terminal disconnects the internal power amplifier
section from the preamplifier section.
7. INSTALLATION
To prevent the internal temperature rise, keep the unit at least 10 cm away from objects that may obstruct air
flow.
Over 10 cm
Over 10 cm
Over 10 cm
7
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8. RACK MOUNTING
To mount the unit in a standard 19" equipment rack, use the optional MB-25B Rack Mounting Bracket.
Attach the MB-25B to the unit using the supplied 4 screws. When using other screws, each screw must be
shorter than 16 mm.
M4 x 16 Machine screw included in MB-25B
MB-25B
9. CONTROL SETTINGS
Output levels are adjustable with individual volume controls.
For music play or announcements, adjust the corresponding
volume control so that the red indicator doesn't light. Note
that the sound quality is downgraded when the red indicator
remains lit.
2
T
U
IMP
1
T
U
P
IN
S
S
A
B
To prevent the accidental change of the settings of input
volume and tone (Bass and Treble) controls, remove their
knobs after setting them to the desired position and attach
the supplied or optional YA-920 Volume Control Covers
instead.
YA-920
Control knob
10. DIMENSIONAL DIAGRAM (Applicable to all models)
Unit: mm
18
326.5
7
420
This figure represents the A-724.
8
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11. BLOCK DIAGRAM
9
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12. SPECIFICATIONS
[A-706]
Power Source
120 V AC, 60 Hz
60 W
Rated Output
Power/Current Consumption
155 W (rated output), 68 W (based on UL60065),
under 250 mA (when power switch is OFF)
Frequency Response
Distortion
50 – 20,000 Hz ( 3 dB)
Under 2% at 1 kHz, rated power
Input
INPUT 1 – 6: –70 to –50 dB*, 600 Ω (MIC)/–10 dB*, 600 Ω (LINE)
INPUT 1:
Transformer-balanced, removable terminal block (3 pins)
INPUT 2 – 6: Electronically-balanced, removable terminal block (3 pins)
Note: Each of INPUT 2 and 3 can be converted into transformer-
balanced type by using an optional transformer IT-455.
INPUT 7 – 8 (LINE): –10 dB*, 10 kΩ, unbalanced, RCA jack
MODULE:
PWR AMP IN:
–10 dB*, 10 kΩ
0 dB*, 10 kΩ, unbalanced, RCA jack
(An equalizer or other signal processor connectable between PRE AMP
OUT and PWR AMP IN terminals)
Output
REC OUT:
0 dB*, 600 Ω, unbalanced, RCA jack
PRE AMP OUT: 0 dB*, 600 Ω, unbalanced, RCA jack
SPEAKER OUT: 70 V line (83 Ω), 25 V line (10 Ω), and 4 – 16 Ω,
removable terminal block (4 pins)
Phantom Power (+23 V DC)
ON or OFF for each INPUT 1 – 6 (MIC input) with switch setting
S/N Ratio
(Band pass: 20 – 20,000 Hz)
Over 55 dB (INPUT 1 – 6, mic trim volume: max., 600 Ω terminated)
Over 70 dB (INPUT 1 – 6, mic trim volume: min., 600 Ω terminated)
Over 76 dB (Master volume: max.)
Over 90 dB (All input volume: min.)
Tone Control
Control Input
Bass: 10 dB at 100 Hz, Treble: 10 dB at 10 kHz
REMOTE VOLUME: Removable terminal block
POWER REMOTE: No-voltage make contact input, removable terminal
block, Open voltage: Under 14 V DC, Short-circuit:
Under 0.5 mA
MUTE CONTROL: No-voltage make contact input, removable terminal
block, Open voltage: Under 17 V DC, Short-circuit:
Under 1.5 mA
Indicator
5-point LED output level meter, Power indicator LED
Operating Temperature
Finish
–10°C to +40°C
Panel: ABS resin, black, hair line
Case: Steel plate, black
Dimensions
Weight
420 (w) x 107.7 (h) x 351.5 (d) mm
9.5 kg
* 0 dB = 1 V
Note: The design and specifications are subject to change without notice for improvement.
• Accessories
AC power cord (2 m) ........................................ 1
Removable terminal plug (4 pins) .................... 1
Removable terminal plug (6 pins) .................... 1
Removable terminal plug (3 pins) .................... 6
Volume control cover YA-920 .......................... 4
• Optional products
Input transformer: IT-455
Rack mounting bracket: MB-25B
Volume control cover: YA-920
900 series module
Available as a service part with the
order code 114-03-120-40.
Additionally needed is the insulating
sheet also available as a service part
with 131-27-700-90.
10
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[A-712]
Power Source
120 V AC, 60 Hz
120 W
Rated Output
Power/Current Consumption
285 W (rated output), 110 W (based on UL60065),
under 400 mA (when power switch is OFF)
Frequency Response
Distortion
50 – 20,000 Hz ( 3 dB)
Under 2% at 1 kHz, rated power
Input
INPUT 1 – 6: –70 to –50 dB*, 600 Ω (MIC)/–10 dB*, 600 Ω (LINE)
INPUT 1:
Transformer-balanced, removable terminal block (3 pins)
INPUT 2 – 6: Electronically-balanced, removable terminal block (3 pins)
Note: Each of INPUT 2 and 3 can be converted into transformer-
balanced type by using an optional transformer IT-455.
INPUT 7 – 8 (LINE): –10 dB*, 10 kΩ, unbalanced, RCA jack
MODULE:
PWR AMP IN:
–10 dB*, 10 kΩ
0 dB*, 10 kΩ, unbalanced, RCA jack
(An equalizer or other signal processor connectable between PRE AMP
OUT and PWR AMP IN terminals)
Output
REC OUT:
0 dB*, 600 Ω, unbalanced, RCA jack
PRE AMP OUT: 0 dB*, 600 Ω, unbalanced, RCA jack
SPEAKER OUT: 70 V line (42 Ω), 25 V line (5.2 Ω), and 4 – 16 Ω,
removable terminal block (4 pins)
Phantom Power (+23 V DC)
ON or OFF for each INPUT 1 – 6 (MIC input) with switch setting
S/N Ratio
(Band pass: 20 – 20,000 Hz)
Over 55 dB (INPUT 1 – 6, mic trim volume: max., 600 Ω terminated)
Over 70 dB (INPUT 1 – 6, mic trim volume: min., 600 Ω terminated)
Over 76 dB (Master volume: max.)
Over 90 dB (All input volume: min.)
Tone Control
Control Input
Bass: 10 dB at 100 Hz, Treble: 10 dB at 10 kHz
REMOTE VOLUME: Removable terminal block
POWER REMOTE: No-voltage make contact input, removable terminal
block, Open voltage: Under 14 V DC, Short-circuit:
Under 0.5 mA
MUTE CONTROL: No-voltage make contact input, removable terminal
block, Open voltage: Under 17 V DC, Short-circuit:
Under 1.5 mA
Indicator
5-point LED output level meter, Power indicator LED
Operating Temperature
Finish
–10°C to +40°C
Panel: ABS resin, black, hair line
Case: Steel plate, black
Dimensions
Weight
420 (w) x 107.7 (h) x 351.5 (d) mm
12 kg
* 0 dB = 1 V
Note: The design and specifications are subject to change without notice for improvement.
• Accessories
AC power cord (2 m) ........................................ 1
Removable terminal plug (4 pins) .................... 1
Removable terminal plug (6 pins) .................... 1
Removable terminal plug (3 pins) .................... 6
Volume control cover YA-920 .......................... 4
• Optional products
Input transformer: IT-455
Rack mounting bracket: MB-25B
Volume control cover: YA-920
900 series module
Available as a service part with the
order code 114-03-120-40.
Additionally needed is the insulating
sheet also available as a service part
with 131-27-700-90.
11
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[A-724]
Power Source
120 V AC, 60 Hz
240 W
Rated Output
Power/Current Consumption
565 W (rated output), 215 W (based on UL60065),
under 60 mA (when power switch is OFF)
Frequency Response
Distortion
50 – 20,000 Hz ( 3 dB)
Under 2% at 1 kHz, rated power
Input
INPUT 1 – 6: –70 to –50 dB*, 600 Ω (MIC)/–10 dB*, 600 Ω (LINE)
INPUT 1:
Transformer-balanced, removable terminal block (3 pins)
INPUT 2 – 6: Electronically-balanced, removable terminal block (3 pins)
Note: Each of INPUT 2 and 3 can be converted into transformer-
balanced type by using an optional transformer IT-455.
INPUT 7 – 8 (LINE): –10 dB*, 10 kΩ, unbalanced, RCA jack
MODULE:
PWR AMP IN:
–10 dB*, 10 kΩ
0 dB*, 10 kΩ, unbalanced, RCA jack
(An equalizer or other signal processor connectable between PRE AMP
OUT and PWR AMP IN terminals)
Output
REC OUT:
0 dB*, 600 Ω, unbalanced, RCA jack
PRE AMP OUT: 0 dB*, 600 Ω, unbalanced, RCA jack
SPEAKER OUT: 70 V line (21 Ω), 25 V line (2.6 Ω), and 4 – 16 Ω,
removable terminal block (4 pins)
Phantom Power (+23 V DC)
ON or OFF for each INPUT 1 – 6 (MIC input) with switch setting
S/N Ratio
(Band pass: 20 – 20,000 Hz)
Over 55 dB (INPUT 1 – 6, mic trim volume: max., 600 Ω terminated)
Over 70 dB (INPUT 1 – 6, mic trim volume: min., 600 Ω terminated)
Over 76 dB (Master volume: max.)
Over 90 dB (All input volume: min.)
Tone Control
Control Input
Bass: 10 dB at 100 Hz, Treble: 10 dB at 10 kHz
REMOTE VOLUME: Removable terminal block
POWER REMOTE: No-voltage make contact input, removable terminal
block, Open voltage: Under 14 V DC, Short-circuit:
Under 0.5 mA
MUTE CONTROL: No-voltage make contact input, removable terminal
block, Open voltage: Under 17 V DC, Short-circuit:
Under 1.5 mA
Indicator
5-point LED output level meter, Power indicator LED
Operating Temperature
Finish
–10°C to +40°C
Panel: ABS resin, black, hair line
Case: Steel plate, black
Dimensions
Weight
420 (w) x 107.7 (h) x 351.5 (d) mm
13.5 kg
* 0 dB = 1 V
Note: The design and specifications are subject to change without notice for improvement.
• Accessories
AC power cord (2 m) ........................................ 1
Removable terminal plug (4 pins) .................... 1
Removable terminal plug (6 pins) .................... 1
Removable terminal plug (3 pins) .................... 6
Volume control cover YA-920 .......................... 4
• Optional products
Input transformer: IT-455
Rack mounting bracket: MB-25B
Volume control cover: YA-920
900 series module
Available as a service part with the
order code 114-03-120-40.
Additionally needed is the insulating
sheet also available as a service part
with 131-27-700-90.
133-12-920-9A
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