Operation Instruction Manual
TOA NEW 900 SERIES
P906A
POWER AMPLIFIER
Features
1 Wide frequency response; 20 — 20,000 H z, ±1 d B
2 Low distortion and noise level
3 Excellent output regulation
4 A ful l range of plug-in modules
5 Self-protecting circuitry design
6 Varied output impedances; 4 and 8 ohms, 25 and 70 volts
7 Input level switch (selectable 1,000mV/100mV)
8 Portable or rack-mounting type
P912A
General Descriptions
The TOA P-906A and P-912A Power Amplifiers deliver up to 60
watts and 120 watts of power
harmonic distortion (THD) from 20 to 20,000 Hz (transformerless
4-ohm output). The P-906A and P-912A have a high-impedance
direct input and an input port (edge connector) to accept one
module accessory. Module selection is determined by application
among the TOA plug-in modules:
The H-01 series, H-02 series and H-03 series Microphone Preamplifiers, E-01 Mag. Phono Preamplifier, the X-01 series Auxiliary
Preamplifiers for high-level sources, the B-01 series Bridging Transformers for bridging high-impedance lines, the L-01 series Line
Matching Transformers for matching 600-ohm lines, 1-01 Paging
Input for combining with the TOA Intercom System EXES-1000,
EXES-5000 and EX-16, and the S-01, S-02 and S-03 Tone signal
generators for generating attention-getting signals and 1 kHz sine
wave for testing within the total system.
The P-906A and P-91 2A have a l ow-c ut sw it ch for a cu tof f frequency
of 60 Hz, and an input-level switch for input sensitivity of 1V
(0dBv) or 100mV (—20dBv). Output terminals provide connections
for 4-ohm and 8-ohm speakers, plus 25-volt and 70-volt speaker distribution outlets.
With plug-in modules, the TOA P-906A and P-912A Power Amplifiers may be used as a pre/power amplifier.
The P-906A and P-912A can be rack mounted by using the MB-931
Rack-mounting Bracket accessory. The PF-911 Perforated Panel
(1.73 inches, 1 rack unit) accessory provides suitable ventilation,
finished in color to match the P-906A and P -912A.
respectively
at
less
than 0.5%
total
Toa Electric Co., Ltd.
KOBE, JAPAN
133-02-740-6
Printed in Japan
Front Panel Controls and Features Rear Panel Controls and Features
Item
2
3
1
Name
POWER
ON-OFF
SWITCH
METER
INPUT
VOLUME
CONTROL
Function/Description
Applies line power. Two-position
pushbutton switch for on-off modes.
Indicates the output level of the
amplifier. At rated output, it shows
0 VU (at continuous sine-wave
signal input).
When power is turned on, meter
illuminates.
Adjusts gain of INPUT.
Item
1
2
3
4
5
6
7
8
9
10
Nam e
AC POWER
SUPPLY
CORD
AC OUTLET
(Unswitched)
AC FUSE
OUTPUT
FUSE
OUTPUT
TERMINALS
MODULE
INPUT
PORT
LOW-CUT
SWITCH
INPUTLEVEL
SWITCH
DIRECT
INPUT
TERMINAL
EARTH
TERMINAL
Function/Description
Connects to power source.
Provides AC power for auxiliary equipment
with power consumption of up to 500W.
Protects amplifier from excessive current
drain. Replace only with same type fuse.
Refer to qualified service personnel if fuse
blows repeatedly.
P-906A
AC FUSE
OUTPUT FUSE
Connect to speakers.
Accepts PLUG-IN MODULES which are
optionally available. Module selection is
determined by application.
Cuts off unnecessary low frequency.
Selects input sensitivity. Place in "1V
(0dBv)" position when normally used
as a
power
Note: The position of INPUT-LEVEL
SWITCH should be changed according to
modules used or equipment connected to
DIRECT INPUT TERMINAL.
Connects directly to external equipment
without using modules. Unbalanced
10k ohms.
Normally connects to a record player's
ground.
amplifier.
250V 3A
250V 6A
P-912A
250V 5A
250V 10A
— —
1
Input Connections
Two types of input terminals are provided on the rear for input
•
connections.
(1) 2P terminal (marked HOT, E)
It is provided for direct input (unbalanced, 10k ohms) without
using plug-in module. This terminal is directly connected with
a potentiometer inside.
(2) Plug-in module input
Select the desired module according to application.
Plug th e module into INPUT PORT, sliding it between the guide
•
rails, and secure with two screws.
When INPUT PORT is not occupied, cover the PORT with the
•
blank panel, and secure it wit h screws.
Be sure that INPUT-LEVEL SWITCH is in the proper position
•
for the module used or the equipment connected to DIRECT
INPUT TERMINAL.
When the P-906A or P-912A is used in combination with a mixer
•
preamplifier or serves as an incremental power amplifier, normally
place INPUT LEVEL SWITCH in "1V ( 0 dB v)" position,
Plug-in Modules and Input Level SW Setting
Plug-in Modules
Balanced low impedance microphone preamp. module
(with presettable low-cut filter, high - cut filter a nd
gain controls)
Balanced low impedance microphone preamp. module
(with pressetable low-cut filter, high-cut filter
and gain controls, and remote control facilities)
Balanced low impedance microphone preamp. module
(with presettable low-cut filter and gain controls)
Balanced low impedance microphone preamp. module
(with presettable low-cut filter and gain controls,
and remote control facilities)
Unbalanced high impedance microphone preamp. module
(with presettable low-cut filter and gain controls)
Equalized mag. phono preamp. module
(with presettable gain control)
Unbalanced high impedance auxiliary preamp. module
(with presettable gain control)
Unbalanced high impedance auxiliary preamp. module
(with presettable gain control and remote control
facilities)
Balanced 10k
Balanced 600 line matching transformer module
Balanced paging input module
(with presettable gain control)
Signal tone generator module
(with presettable output level control)
1 kHz s in e wa ve
Yelp and buzzer
One-tone chime and continuous one-tone chime
bridging transformer module
Input Level SW Setting
Model
No,
H-01
H-21
H-02
H-22
H-03
E-01
X-01
X-21
B-01
L-01
l-01
S-01
S-02
S-03
See PLUG-IN MODULES for details.
1V
(0dBv)
-
_
-
-
-
-
-
-
0
o
-
-
100mV
(—20dBv)
0
0
0
o
0
o
0
o
0
o
0
0
— 2 —
Output Connections P-906A, P-912A
Installation
The speaker outputs of the amplifier are 4 , 8 , 25V and 70V.
Connect speakers to one of these outputs.
Class 2 wiring may be used.
Since these outputs consist of 8 , 25V and 70V via the output
transformer (matching transformer) and direct output of 4 , the
connecting method differs in each case. See the f o l l o w i n g di a gr am s .
Note: Impedances indicated below imply total speaker system
(load) impedance.
When connecting speakers to any one of the outputs of 8 O, 25V
•
or 70V (BALANCED TRANSFORMER OUTPUT);
Do not block cover ventilation holes.
•
•
The amplifier should not be placed in areas;
1. with poor ventilation.
2. exposed to direct sunlight.
3. with high ambient temperature or adjacent to heat-generating
equipment.
4. with high humidity or dusty levels.
5. susceptible to vibration.
Note:
When the temperature of heat sink exceeds 105°C, the protection
circuit is activated and the output is disconnected from the
circuit. The signal automatically begins to be output as the
temperature goes down. In such a case, confirm whether or not
unit is overloaded or operated on an excessive output.
Note:
In this case, the LOW-CUT SWITCH should be in "CUT" position. This amplifier is characteristically flat even in the low frequency range. Therefore, in TRANS OUTPUT, the acoustic
effect and frequency-response characteristics may be altered.
In TRANS OUTPUT, cut off unnecessary low frequency to obtain the best acoustic condition.
Place
the
SWITCH in "CUT" position
• When connecting speakers to the 4 output. (UNBALANCED
DIRECT OUTPUT);
LOW—CUT
— 3 —
Operation
Rack Mounting
When all connections are completed, turn power switch on. Then,
the meter is illuminated. Approx. 5 seconds after switching power
on, the amplifier comes into operation.
ADJUSTMENT OF VOLUME CONTROL
Adjust the input volume control to obtain appropriate output level.
In normal use of BGM playing or announcement, the deflection of
the meter is recommended to be within the range as indicated in the
drawing. Tone quality will be considerably deteriorated if the
pointer indicates around 0 VU.
In normal use of BGM
playing or announcement.
The pointer of meter indicates 0 VU if continuous signals like sine
waves are applied to the input of the amplifier.
Continuous signals
When the power amplifier is used in combination with a mixer pre-
amplifier, adjust the total gain at the mixer preamplifier with the
gain setting of the power amplifier at maximum.
To mount the amplifier in a standard 19-inch equipment rack, use
the MB-931 Rack-mounting Bracket accessory.
Remove 4 screws securing case.
MB-931
(Silver)
(OPTION)
Fix the MB-931 with attached 4 screws.
The length of the screws should not
exceed 12mm (1/2 inches).
Perforated Panel
PF-911 (OPTION)
(Silver)
Output Fuse
•
Each amplifier has an output fuse to protect the amplifier from
short-circuiting at the output or overloading. Check the fuse when
speakers connected do not sound even if the meter deflects
normally. If the fuse blew, replace with the same type fuse after
confirming the following points.
(1 ) Speaker cables are not short-circuited or the load does not
exceed the rating specified.
(2) Wiring i s correctly done at the output terminal board.
If two or more amplifiers are mounted in
an equipment rack, space should be provided between the units for ventilation.
The PF-911 Perforated Panel is recommended for this purpose.
Servicing
•
Unpacking
Upon receipt of the amplifier shipment, please inspect for any
damage incurred in transit. If damage is found, please notify your
local TOA representative and the transportation company
immediately.
State date, nature of damage, whether any damage was noticed on
the shipping container, prior to unpacking. Please give waybill
number of shipping order.
Failure
•
Should amplifier fail, contact your nearest TOA authorized contractor or service center.
— 4 —
Block Diagram P-906A , P-912 A
—5 —
Specifications
P-906A P-912A
Type
Output Power
Power Band Width
Frequency Response
Total Harmonic Distortion
Inputs
Input Sensitivity/Impedance
Outputs
(D) - Direct
(T) - Transformer
Output Regulation (1 kHz)
Signal to N ois e Rat io
(Band
Pass
20 —
20,000
Hz)
Power amplifier
60 watts RMS
(D) 20—20,000 H z 0.5% THD
(T) 50 —20,000 Hz 0.5% THD
(D) 20— 20,000 Hz, ±1 dB
(T) 20— 15,000 Hz, ±1 dB
(T) 20— 20,000 Hz,
0.0 1 % a t 1 kHz, rated output
One Input Port : Port accepts any input module except T-01, which cannot be used.
One Direct Input
Note : Use of direct input prohibits use of modular input port.
Input Port : 100 mV or 1,000 mV (Switchable)/10k ohms
Direct Input : 100 mV or 1,000 mV (Switchable)/10k ohms
Main (T) : 8 ohms, 25 & 70 volts, balanced
Main (D): 4 ohms, unbalanced
(D) Less than 0.5 dB, no load to fu ll load (T ) Less than 1.0 dB, no load to ful l load
Input level switch in 0 dBv (1,000 mV) position : 108 dB
Input level switch in -20 dBv (100 mV) position : 90 dB
+1dB
—
3db
120 watts RMS
Controls
Indicator
Protection
Connectors
Power Consumption
Temperature Range
Dimensions in mm (inches)
(high) x (wide) x (deep)
Weight (without input modules)
Color
Other Features
1 Input gain control
1 Input level switch
1 Power ON/OFF switch
1 Low-cut switch (60 Hz, 6 dB/octave)
1 Illuminated VU meter
Self-protection, with 2 AC fuses (1 inside) and 1 output fuse
Inputs ................ .Card-edge connector and screw-terminal strip
Outputs ............... .Screw-terminal strip
AC outlet .............. .3-pin grounding type
AC power cord/plug ........ .SJT, 3-prong type
AC 1 20 volts, 60 Hz, 100 watts
-10°C to+60°C (12°F to 140°F)
145 (5.71") x 420 (16.54") x 315 (12.40")
Rack-mounting space size "3U" (5.21")
10.4
kg
(22.9
Ibs.)
Output disconnected fo r approx. 5 sec after switching power on.
Silver
Specifications are subject to change without notice.
AC 120 volts, 60 Hz, 180 watts
14.2kg (31.2 Ibs.)
— 6 —
Plug-in Modules and Accessories
(OPTION)
The TOA PLUG-IN MODULES are suitable for TOA 900 SERIES
MIXER POWER AMPLIFIERS A-901A, A-903A, A-906A, and
A-912A MIXER PREAMPLIFIER M-900A, and POWER AMPLIFIERS P-906A, P-912A and P-924. Owing to wide selection of
MODULES, the desired applications will be obtained. The various
types of connectors can also meet the needs of equipment to be
connected. MICROPHONE PREAMPLIFIER H-01 series, H-21 and
H-31 incorporates controls for high-cut, low-cut and gain, H-02
series, H-22, H-32 and H-03 series controls for low-cut and gain.
A gain control is built in MAG. PHONO PREAMPLIFIERS E-01
and E-11 series, AUXILIARY PREAMPLIFIERS X-01 and X-11
series and X-21, PAGING INPUT I-01 and LINE OUTPUT T-01
series. T-01 series is an output module with transformer, serving
as a line output for recording, etc..
PAGING INPUT I-01 is specially designed to associate with TOA
INTERCOM SYSTEMS. It accepts paging signals fro m the intercom
station.
A group of special signal generating modules is also available for
catching-attention before announcement and testing within the total
system. ALL PLUG-IN MODULES have handles on their front for
easy insertion and removal.
(INPUT CONNECTIONS, T-01 OUTPUT CONNECTION)
Features:
1. Wide dynamic range
2. Low noise and distorition
3. Wide frequency response
4. Built-in remote volume control circuit (available for models
having 20's in its model number such as H-21)
5. Built-in muting circuit to mute incoming signal when MUTE
TERMINAL is grounded, (available for modules having 10's in
its model number such as X-11)
6. Built-in muting circuit to deliver output signal when MUTE
TERMINAL is grounded, (available for modules having 30's in
its model number such as H-31 )
7. Built-in signal activated muting function (L-41)
8. Presettable gain control (except for B-01, B-11, L-01 and L-11)
9. Microphone modules furnished with tone controls (H-01, H-02,
H-21, H-22, H-31, H-32
and
H-03)
— 7 —
TOA NEW 900 SERIES
Plug-in Modules
• FORNT PANEL CONTROLS AND FEATURES
Modules with built-in controls are provided in the following five
types.
— 8 —
GAIN CONTROL
SENSITIVITY
CONTROL (L-41S)
NOMINAL POSITION
MARK
This adjusts gain. Turn clockwise (CW)
to increase and counterclockwise (CCW)
to reduce gain.
Set the gain as low as possible, thereby,
noise can be reduced, and the maximum
permissible input level is raised.
This adjusts sensitivity for muting other
modules having MUTE function. Turn
CW to raise and CCW to lower sensitivity.
Setting position should depend on the
equipment connected with L-41S.
The left figure shows nominal
setting of controls.
LOW-CUT FILTER
CONTROL
330Hz, 6dB/oct
(max. attenuation)
MUTE DELAY
CONTROL (I-01S)
HIGH-CUT FILTER
CONTROL
4.2kHz, 6dB/oct
(max. attenuation)
This provides flat characteristics at full
CW position and attenuation in low
frequency by turning CCW. Adjust it to
obtain proper tone quality. With low-cut,
tone becomes clear.
This adjusts MUTE delay time which is
the duration from signal input to its
output. Turn CW to shorten and CCW
to lengthen the time.
This provides flat characteristics at full
CW position and attenuation in high
frequency by turning CCW. Adjust it to
obtain proper tone quality. With highcut, tone becomes soft.
— 9 —
• SPECIFICATIONS IN COMMON
Load impedance
Mounting
Dimensions in mm (inches)
(H) x (W) x (D)
: 10k-ohms
: Card-edge connector
: 78(3.07)x35(1.38)x88(3.46)
TOA NEW 900 SERIES
Block Diagrams (Plug-in Modules)
— 10 —
Operation and Connections
E-11, X-11, L-11, B-11 Series, H-31 and H-32 (with mute)
•
Connections
(M-900A, A-903A, A-906A, A-912A)
Mute
Terminal
Operation
When the switch is closed,,
a. the signal fed to E-11, X-11, L-11 and B-11 are attenuated by
approx. 60dB. Accordingly a microphone can have a priority at a
time of announcement.
b. the signal fed to H-31 and H-32 are delivered to the amplifier.
(While the switch is opened, the signals are attenuated.)
(Plug-in Modules)
Remoto switch
T-0 1 SERIES (BALANCED 600-ohm LIN E OUTPUT MODULES)
•
This series of modules, of rated output level 1 volt, is used for
transmitting mixing signals of amplifiers to external equipment and
as a REC
It is provided with a presettable gain control.
T-01 Series should be used exclusi vely for TOA 900 series, A-903A,
A-906A, A-912A and M-900A. Use it onl y in Input P ort #5 or #6 of
the above models. It will not operate when connected into other
PORTS.
Approx. 5 seconds after power has been supplied to these modules,
the output signal is transmitted.
•
S-01 (1,000Hz SINE WAVE)
out.
Connections
Remote switch
•
L-41 (with signal activated muting facilities)
When this module accepts the input signal, the mute terminal is
grounded automatically without connection of the remote switch
to the MUTE TERMINAL. It causes the other modules with mute
function, like X-11, to be muted.
Accordingly the signal fed to the L-41 can have a priority.
H-21, H-22 and X- 21 (Remote volume control facilities)
•
Connections
Potentiometer
10k
Remote
volume
control
Input Connection
Operation
Preset the gain control of module and the input volume control of
the corresponding input so that an appropriate sound level may be
obtained through the remote volume control.
It is operated by closing the remote
switch.
S-02 (YELP AND BUZZER)
•
Connections
Yelp signal
Remote switch
Each signal is generated by closing cor-
responding remote switch.
Remote switch
S-03 (ONE-TONE CHIME AND CONTINUOUS ONE-TONE
•
CHIME)
CONNECTIONS
One-tone chime
Remote switch
By closing the remote switch, chime
sounds once.
Continuous one-tone chime
Remote switch
— 11 —
By closing the remote switch, one-tone
chime sounds continuously during the
closure of the switch.
—12—
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