Toa P912A Administrator Guide

Operation Instruction Manual
TOA NEW 900 SERIES
POWER AMPLIFIER P912A
2 Low distortion and noise level
3 Excellent output regulation
4 A full range of plug-in modules
5 Self-protecting circuitry design
6 Varied output impedances; 4 and 8 ohms, 25 and 70 volts
7Input level switch (selectable 1,000mV/100mV)
8 Portable or rack-mounting type
The TOA P-906A and P-912A Power Amplifiers deliver up to 60
watts and 120 watts of power
respectively at less than 0.5% total
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 Pre-
amplifiers, E-01 Mag. Phono Preamplifier, the X-01 series Auxiliary
Preamplifiers for high-level sources, the B-01 series Bridging Trans-
formers 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-912A have a low-cut switch for a cutoff 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 dis-
tribution outlets.
With plug-in modules, the TOA P-906A and P-912A Power Am-
plifiers 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.
133-02-740-6
Printed in Japan
ToaElectricCo.,Ltd.
KOBE, JAPAN
Features
General Descriptions
P906A
1 Wide frequency response; 20 — 20,000 Hz, ±1dB

Item
1
2
3
Name
POWER
ON-OFF
SWITCH
METER
INPUT
VOLUME
CONTROL
Function/Description
Applieslinepower.Two-position
pushbuttonswitchforon-offmodes.
Indicatestheoutputlevelofthe
amplifier.Atratedoutput,itshows
0VU(atcontinuoussine-wave
signalinput).
Whenpoweristurnedon,meter
illuminates.
AdjustsgainofINPUT.
1
Item
1
2
3
4
5
6
7
8
9
10
Nam e
ACPOWER
SUPPLY
CORD
ACOUTLET
(Unswitched)
ACFUSE
OUTPUT
FUSE
OUTPUT
TERMINALS
MODULE
INPUT
PORT
LOW-CUT
SWITCH
INPUT-
LEVEL
SWITCH
DIRECT
INPUT
TERMINAL
EARTH
TERMINAL
Function/Description
Connectstopowersource.
ProvidesACpowerforauxiliaryequipment
withpowerconsumptionofupto500W.
Protectsamplifierfromexcessivecurrent
drain.Replaceonlywithsametypefuse.
Refertoqualifiedservicepersonneliffuse
blowsrepeatedly.
Connecttospeakers.
AcceptsPLUG-INMODULESwhichare
optionallyavailable.Moduleselectionis
determinedbyapplication.
Cutsoffunnecessarylowfrequency.
Selectsinputsensitivity.Placein"1V
(0dBv)"positionwhennormallyused
Note:ThepositionofINPUT-LEVEL
SWITCHshouldbechangedaccordingto
modulesusedorequipmentconnectedto
Connectsdirectlytoexternalequipment
withoutusingmodules.Unbalanced
10kohms.
Normallyconnectstoa recordplayer's
ground.
ACFUSE
OUTPUTFUSE
P-906AP-912A
250V5A 250V3A
250V6A
250V10A
Front Panel Controls and Features Rear Panel Controls and Features
asa power amplifier.
DIRECTINPUTTERMINAL.
— —

Plug-in Modules and Input Level SW Setting
Plug-inModules
Balanced low impedance microphone preamp. module
(with presettable low-cut filter, high-cut filter and
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)
bridging transformer module
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 sine wave
Yelp and buzzer
One-tone chimeand continuous one-tone chime
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
InputLevelSW Setting
1V
(0dBv)
-
_
-
-
-
-
-
-
0
o
-
-
100mV
0
0
0
o
0
o
0
o
0
o
0
0
See PLUG-IN MODULES for details.
•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 the 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 with 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
Input Connections
place INPUT LEVEL SWITCH in "1V (0 dBv)" position,
(—20dBv)
Balanced 10k
— 2 —

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.
•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.
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 following diagrams.
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);
Note:
In this case, the LOW-CUT SWITCH should be in "CUT" posi-
tion. This amplifier is characteristically flat even in the low fre-
quency range. Therefore, in TRANS OUTPUT, the acoustic
effect and frequency-response characteristics may be altered.
In TRANS OUTPUT, cut off unnecessary low frequency to ob-
tain the best acoustic condition.
SWITCH in "CUT" position
•When connecting speakers to the 4 output. (UNBALANCED
DIRECT OUTPUT);
Installation
Output Connections P-906A, P-912A
Place the LOW—CUT
— 3 —

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.
To mount the amplifier in a standard 19-inch equipment rack, use
the MB-931 Rack-mounting Bracket accessory.
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.
Remove 4 screws securing case.
Fix the MB-931 with attached 4 screws.
MB-931 The length of the screws should not
(Silver) exceed 12mm (1/2 inches).
(OPTION)
Perforated Panel
PF-911 (OPTION)
(Silver)
If two or more amplifiers are mounted in
an equipment rack, space should be pro-
vided between the units for ventilation.
The PF-911 Perforated Panel is recom-
mended for this purpose.
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.
•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 is correctly done at the output terminal board.
•
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 con-
tractor or service center.
Operation
Rack Mounting
Servicing
— 4 —

Block Diagram P-906A , P-912 A
—5 —

Type
Output Power
Power Band Width
Frequency Response
Total Harmonic Distortion
Inputs
InputSensitivity/Impedance
Outputs
(D) - Direct
(T) - Transformer
Output Regulation (1 kHz)
Signal to Noise Ratio
Controls
Indicator
Protection
Connectors
Power Consumption
Temperature Range
Dimensions in mm (inches)
(high) x (wide) x (deep)
Weight (without input modules)
Color
Other Features
P-906A P-912A
Power amplifier
60 watts RMS
120 watts RMS
+1dB
—
3db
0.01%at 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 full load (T) Less than 1.0 dB, no load to full load
Input level switch in 0 dBv (1,000 mV) position : 108 dB
Input level switch in -20 dBv (100 mV) position : 90 dB
1 Input gain control
1 Input level 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-edgeconnector 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
AC 120 volts, 60 Hz, 180 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.)
14.2kg (31.2 Ibs.)
Silver
Output disconnected for approx. 5 sec after switching power on.
Specifications are subject to change without notice.
Specifications
(D)20—20,000Hz0.5%THD
1 Power ON/OFF switch
(T)50—20,000 Hz 0.5% THD
(D) 20— 20,000 Hz, ±1 dB
(T) 20— 15,000 Hz, ±1 dB
(T)20—20,000Hz,
(Band Pass 20 — 20,000 Hz)
— 6 —

(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 AMPLI-
FIERS 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 from 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 insertionand 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)
Plug-in Modules and Accessories
— 7 —

TOANEW900SERIES
•FORNTPANELCONTROLSANDFEATURES
Moduleswithbuilt-incontrolsareprovidedinthefollowingfive
types.
GAINCONTROL
SENSITIVITY
CONTROL(L-41S)
NOMINALPOSITION
MARK
Thisadjustsgain.Turnclockwise(CW)
toincreaseandcounterclockwise(CCW)
toreducegain.
Setthegainaslowaspossible,thereby,
noisecanbereduced,andthemaximum
permissibleinputlevelisraised.
Thisadjustssensitivityformutingother
moduleshavingMUTEfunction.Turn
CWtoraiseandCCWtolowersensitivity.
Settingpositionshoulddependonthe
equipmentconnectedwithL-41S.
Theleftfigureshowsnominal
settingofcontrols.
LOW-CUTFILTER
CONTROL
330Hz,6dB/oct
(max.attenuation)
MUTEDELAY
CONTROL(I-01S)
HIGH-CUTFILTER
CONTROL
4.2kHz,6dB/oct
(max.attenuation)
Thisprovidesflatcharacteristicsatfull
CWpositionandattenuationinlow
frequencybyturningCCW.Adjustitto
obtainpropertonequality.Withlow-cut,
tonebecomesclear.
ThisadjustsMUTEdelaytimewhichis
thedurationfromsignalinputtoits
output.TurnCWtoshortenandCCW
tolengthenthetime.
Thisprovidesflatcharacteristicsatfull
CWpositionandattenuationinhigh
frequencybyturningCCW.Adjustitto
obtainpropertonequality.Withhigh-
cut,tonebecomessoft.
•SPECIFICATIONSINCOMMON
Loadimpedance
Mounting
Dimensionsinmm(inches)
(H)x (W)x (D)
:10k-ohms
:Card-edgeconnector
:78(3.07)x35(1.38)x88(3.46)
Plug-inModules
— 8 —
— 9 —

TOA NEW 900 SERIES
Block Diagrams (Plug-in Modules)
— 10 —

•
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.)
•
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
Remoto switch
•T-01 SERIES (BALANCED 600-ohm LINE 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 out.
It is provided with a presettable gain control.
T-01 Series should be used exclusively for TOA 900 series, A-903A,
A-906A, A-912A and M-900A. Use it only in Input Port #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)
Connections
Remote switch
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
By closing the remote switch, one-tone
chime sounds continuously during the
closure of the switch.
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.
Input Connection
Potentiometer
10k
Remote
volume
control
Operation and Connections
(Plug-inModules)
— 11 —

—12—