Toa A-903A, A-906A, A-912A Operating Instructions Manual

Operating Instruction Manual

TOA NEW 900 SERIES

MIXER POWER AMPLIFIER

Features

General Description

A-903A
A-906A
A-912A

1 6-channel mixer power amplifier
2 Wide frequency response; 20 — 20,000Hz, ±1dB
3 Low distortion and noise level
4 Excellent output regulation

5 Bass and treble controls
6 Bridging input/output
7 Signal processing input/output
8 Self-protect ing circuitry design
9 Varied output impedances; 4 and 8 ohms, 25 and 70 volts

10 A full range of plug-in modules
11 Portable or rack-mounting type

The TOA A-903A, A-906A and A-912A Mixer Power Amplifiers
control and mix up to six independent input signals. The A-903A
deli vers up to 30 wa tts of output power, t he A-906A 60 watts and
the A-912A 120 watts. Optional accessory modules are available for
use with th e A903A, A-906A and A-91 2A to provide versatility for
a wide range of operating applications. Edge connectors on the rear
of the unit permit the selection of the TOA plug-in modules : The
H-01 series, H-02 series and H-03 series Microphone Preamplifiers,
the E-01 and E-11 Mag. Phono Preamplifiers, the X-01 series and
X-11 series Auxiliary Preamplifiers for high-level sources, the B-01
series and B-11 series Bridging Transformers for bridging high­impedance lines, the L-01 series Line Matching Transformers for
matching 600-ohm lines, I-01 Paging Input for combining with TOA

Intercom Systems EXES-1000, EXES-5000 and EX-16, T-01 series

Line Outputs for matching 600-ohm lines 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. Other
features include a muting function. Sources fed to particular input
module accessories are muted by short-circuiting at MUTE
TERMINALS on the rears. To perform this function, Module E-11,
X-11 series or B-11 series is required.
The TOA A-903A, A-906A and A-912A Mixer Power Amplifiers
have output terminals to match 4- or 8-ohm speaker systems, or
speaker distribution systems may be connected to the 25- or 70-volt
terminals. The A-903A, A-906A and A-912A can be rack mounted
by using Rack-mounting Bracket accessories MB-921 (for A-903A)
or MB-931 (f or A-9 06A and A - 912A). The PF-911 Perforated Panal
(1.73 inches, 1 rack unit) accessory provides suitable ventilation,
finished in color to match the A-903A, A-906A and A -912A.

Toa Electric Co., Ltd.

KOBE, JAPAN

TOA NEW 900 SERIES

Front Panel Controls and Features

A-903A

Item

1

2

3

4

5

6

7

Name

POWER ON-OFF

SWITCH

METER

INPUT VOLUME

CONTROLS

BASS CONTROL

TREBLE CONTROL

TONE SWITCH

MASTER VOLUME

CONTROL

A-906A, A-912A

Function/Description

Applies line power. Two-position push button
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.

Adjust gain of INPUT #1 – #6 respectively.

Adjusts bass response.
Turn cl o c kw i se ( CW ) to boost and counterclockwise
(CCW) to attenuate the bass response. Tone is flat

at center.

Adjusts treble response.
Turn CW to boost and CCW to attenuate the treble

response. Tone is fla t at center.

Selects IN/DEFEAT of the BASS and TREBLE

Cont rols . When this button is depressed (
BASS and TREBLE Controls are active. ( I N )

Whe n pressed again (

make tone flat. (TONE DEFEAT)
Adjusts overall gain of unit.

), they become i nactive to

), the

Block Diagram

— 1 —

Rear Panel Controls and Features

A-903A

Item

1

2

3

4

5
6

7
8

9

10

11

12

13

14

Name

AC POWER

SUPPLY CORD

AC OUTLET

(Unswitched)

AC FUSE

OUTPUT FUSE

OUTPUT TERMINALS
MODULE INPUT

PORTS

LOW-CUT SWITC H
LINK SWITCH

AUX OUT

POWER AMP IN

PREAMP OUT

BRI DG IN G INPUT/

OUTPUT

MUTE TERMINAL

EARTH TERMINAL

A-906A, A-912A

Function/Description

Connects to power source.

Provides AC power fo r auxiliary equipment with

power consumption of up to 500W.

Prevents excessive current flow.

AC FUSE 250V 2A 250V 3A 250V 5A
OUTPUT FUSE 250V 3A 250V 6A 250V 10A

Connect to speakers.

Accept PLUG-IN MODULES which are optionally
available. Module selection is determined by
application.

Cuts off unnecessary low frequency.
Disconnects between preamplifier and power amplifier

when this switch is turned to the "OUT" side, and
other equipment can be connected.

Provides connections for a booster amplifier or a tape
recorder. The input impedances of the equipment
should be of more than 10k ohms.

When using this terminal, set LIN K SWITCH to "OUT"
position.

Connects to a signal processing equipment such as a

limiter, an equalizer etc. The input impedances of the
equipment should be of more than 600 ohms.

In this case, the LI NK SW should be set in the "OUT"

position.

This terminal is used as a mixing bus. Mixina is achieved
when the similar terminal of another amplifier is
connected to this terminal. The output level taken from
this terminal is independent of the MASTER VOLUME

CONTROL, BASS and TREBLE CONTROLS so that the

terminal can also be used as recording output. The

input impedances of the equipment to be connected

here should be of more than 10k ohms.
With modules employing muting function, which are

optionally available, the input signals fed to the
modules are muted by short-circuiting at this terminal.

Normally connects to a record player's ground.

(A-903A) (A-906A) (A-912A)

— 2 —

TOA NEW 90 0 SERIES

Input Connections

This unit has six INPUT PORTS for PLUG-IN MODULES. Select
the desired ones for each application.

Plug the modules into INPUT PORTS, sliding them between the
guide rails, and secure each with two screws.

When not all INPUT PORTS are occupied, cover the vacant

PORTS with blank panels, and secure them with screws.

PLUG-IN MODULES are provided in the following:

Balanced low impedance microphone
premp module (with presettable low-cut

filter, high-cut filter and gain controls)

Balanced low impedance microphone
preamp module (wit h presettable low-cut

filter and gain controls)

Equalized mag. phono preamp. module
(with presettable gain control)
Unbalanced high impedance auxiliay
preamp module (with presettable

gain control)

Balanced 10k
Balanced 600

transformer module

Balanced paging input module
(with presettable gain control and MUTE Delay)
Balanced 600
(with presettable gain cont rol)

Signal tone generator module

(with presettable output level control)

1kHz sine wave

Yelp and buzzer

One-tone chime and co ntinuous one-tone chime

*With H-21 , H-22 and X-21 modules employing volume remote

control functions, connecting a potentiometer (10k ohms) to the
terminal of any of these modules permits the sound volume to be
remotely controlled by means of the connected potentiometer.

* H-31 and H-32 modules incorporate muting functions. If a switch

is connected to MUTE TERMINAL on the rear panel of the ampl i-

fier and closed, these input signals can be passed through. When

the switch is opened, the input signal is muted.

* E-11, X-11, B-11 and L-11 modules incorporate muting functions.

If a switch is connected to MUTE TERMINAL on the rear panel

of the amplifier and closed, these input signals can be muted.

* L-41 incorporates signal activated muting function. Incoming

input signal causes mute terminal to be grounded.

* T-01 is used to feed out mixed signals to external equipment.

*T-01 should be inserted o nly in INPUT POR T #5 or #6.

(See PLUG-IN MODULES for details)

bridging transformer module

line matching

line output module

H-01,

H-02,

X-01,

L-01,

H-21,

H-31

H-22,

H-32

E-01,

E-11

X-11,

X-21

B-01 , B-11

L-11,

L-41

T-01

I-01

S-01
S-02
S-03

Output Connections A-903A

The speaker outputs of the amplifier are 4
70V

(167

Connect speakers to one of these outputs.
Class 2 wiring may be used.

Since these outputs consist of 4
transformer (matching transformer) and direct output of 8
connecting method differs in each case.

See the following diagrams.

Note: Impedances indicated below imply total speaker system

When connecting speakers to any one of the outputs of 4
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

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.

When connecting speakers to the 8
(UNBALANCED DIRECT OUTPUT);

).

, 25V and 70V via the output

(load) impedances.

output.

8

,

, 25V (21

) and

, the

,25V

— 3 —-

Output Connections P-906A, P-912A

Installation

, 8

The speaker outputs of the amplifier are 4
Connect speakers to one of these outputs.

Class 2 wiring may be used.
Since these outputs consist of 8
transformer (matching transformer) and direct output of 4
connecting method di ffers in each case. See the following diagrams:

Note: Impedances indicated below imply total speaker system

(load) impedances.

When connecting speakers to any one of the outputs of 8
or 70V (BALANCED TRANSFORMER OUTPUT);

(A-906A)

(A-912A)

, 25V and 70V via the output

, 25V and

70V.

, the

, 25V

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 dust 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.

When connecting speakers to the 4
DIRECT OUTPUT);

(A-906A, A-912A)

output. (UNBALANCED

— 4 —

TOA NEW 900 SERIES

Operation

When all connections are completed, turn power swit ch on.
Then, the meter is illuminated. Approx. 5 seconds after switching
power on, the amplifier comes into operation.

ADJUSTMENT OF VOLUME

Adjust the individual input and master volume controls 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.

ADJUSTMENT OF TONE QUALITY

When adjusting tone quality, place the TONE SWITCH in "IN"

position, thus activating the BASS and TREBLE CONTROLS. Each
control provides frequency-response characteristics of flat in center,

boost in CW and attenuation in CCW positions.

When tone controls are unnecessary, place the TONE SWITCH in

"DEFEAT" mode.

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.

Rack Mounting

To mount the amplifier in a standard 19-inch equipment rack, use
the MB-9 21 or MB-931 Rack-mounting Bracket accessory. (OPTION)

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 im-

mediately.

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.

— 5 —

Specifications

Type

Output Power

Power Band Width

Frequency Response

Total Harmonic Distortion

Inputs

Input Sensitivity/Impedance

Preamp OUT/Power Amp IN

Outputs

(D) = Direct

(T) = Transformer

Output Regulation (1 kHz)

Signal to Noise Ratio

(Band

Pass

20 —

20,000

Hz)

Tone Controls Centered

Tone Controls

Controls

Indicator

Protection

Connectors

Power Consumption

Temperature Range

Dimensions in mm (inches)

(high) x (wide) x (deep)

Weight (without input modules)

Color

Standard Accessories

Other Features

A-903A

6-channel mixer power amplifier

30 watts RMS

20 — 20,000 H z, 0.5% THD

(D)

50 — 20,000 H z, 0.5% THD

(T)
(D) 20 — 20,000 Hz, ±1 dB

(T ) 20 — 15,000 H z , ±1 dB
(T) 20 — 20,000 Hz, ±1dB

0.02% at 1 kHz, rated output

Si x Input Ports: Each port accepts any input module except T-01. Use T-01 only in port #5 or #6.

One Bridging Input/Output

Input Ports #1 to #6 : 100 mV/10k ohms
Bridging Input/Output: 100 mV/3.3k ohms

1,000 mV into 600 ohms/1,000 mV, 10k ohms

Main (T ): 4 ohms, 25 & 70 volts

Ma in (D): 8 ohms, unbalanced
Aux : 10k ohms, 1,000 mV

AC 120 volts, 60 Hz, 60 watts

101 (3.98") x 420 (16.54")

x 265 (10.43")

Rack-mounting space size "2U"
(3.46")

balanced

(D ) Less than 0.5 dB , no load to fu l l load (T ) Less tha n 1.0 dB, no load t o fu ll load

Master volume min. : 90 dB
Master volume max . : 77 dB

Power amplifier only: 105 dB

Bass; ±10 dB at 100 Hz: Treble; ±10 dB at 10 kHz

6 Input gain controls

1 Bass tone control
1 Power ON/OFF switch
1 Tone defeat switch

1 Illuminated VU meter

Self-protection, with 2 AC fuses (1 inside) and 1 output fuse.

Input #1 to #6
Bridging

Mixer preamp. output

Power amp. inpu t

Aux output
Output
Mute

AC power cord/plug

AC outlet

AC 1 20 volts, 60 Hz, 100 watts

-10°C to +60°C (12°F to 140°F)

7.3kg (16.1 Ibs.)

2 Volume control covers

1 Mute terminal plug

Output disconnected for approx. 5 sec after switching power on.

Muting Function; Accomplished by model E-11, X-1 1, B-11

A-906A

60 watts RMS

— 3 dB

Main (T ) : 8 ohms, 25 & 70 volts, balanced
Main (D ): 4 oh ms, unbalanced

Aux : 10k ohms, 1,000 m V

1 Master gain control
1 Treble tone control

1 Link switch

1 Low-cut switch (60 Hz, 6 dB/octave)

Card-edge connector

RC A phono jack

Screw-terminal strip

2P Socket

SJT, 3-prong type

3-pin grounding type

AC 120 volts, 60 Hz, 180 watts

14 5 (5.71") x 420 (16.54") x 315 (12.40")
Rack-mounting space size "3U" (5.21")

11.4

kg

(25.1

Ibs.)

Silver

A-912A

120 watts RMS

15.2

kg

(33.4

Ibs.)

— 6 —

TOA NEW 900 SERIES

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, an d 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-1 1

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 fr om the intercom

station.
A group of special signal generating modules is also available for

catching-attention before announcement and testing within th e 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 distortion

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

Microphone

Preamplitier

Mag. Phono

Preamplifier

Auxiliary

Preamplifier

Bridging
transformer

Line Matching

Transformer

Paging Input

Line Output

Tone Signal

Generator

Applications

Low Z MIC
with Low & High filters

Low Z MIC
with Low & High filters

and remote volume

control facilities

Low Z MIC
with Low & High filters
and MUTE

Low Z MIC
with Low-cut filter

Low Z MIC
with Low-cut filter

and remote volume
control facilities

Low Z MIC
with Low-cut filter
and MUTE

High Z MIC
with Low-cut filter

———

with MUTE

with MUTE

with remote volume

control facilities

with MUTE

———

with MUTE

with Sign al Activating

Mute

1 kHz Sine Wave

Buzzer/Yelp

One Tone Continuous
Chime Chime

Module

Types

H-01 series

H-21

H-31

H-02 series

H-22

H-32

H-03 series
E-01 series

E-11 series
X-01 series
X-1 1 series

X-21
B-01 series

B-11 series

L-01 series

L-11
L-41

I-01

T-01 series

S-01

S-02
S-03

Source

Impedance

Balanced

200 ohms

Unbalanced
50k ohms

Unbalanced

50k ohms

Unbalanced

220k ohms

Balanced

10k ohms

Balanced
600 ohms

Balanced
600 ohms

[Output

Balanced
600 ohms]

Input Sensitivity

for Rated Output (100 mV)

nominal 1.0 mV

adjustable 0.25~25 mV

nominal 3.2 mV

adju stab le 0.8~8.0 mV

nominal 3.2 mV

adjustable 2.0~5.0 mV

nominal 100 mV

adjustable 100~3,200 mV

125mV

125mV

[M in . 15 mV to activate]

125mV
nominal 3.2V

adjustable 3.2~10V

Gain

nominal 40 dB

adjustable 52~32 d B

nominal 30 dB

adjustable 42~22 dB

nominal 34 dB

adjustable 34~26 dB

nominal 0 dB

adjustable 0~—30 dB

—1dB

—2dB

nominal — 30 dB

adjustable —30~— 40 dB

nominal 20 dB

adjustable 20~4 dB

(1.0V output)

(1.0V~158

mV)

Specifications

Max. Before Clip

into 10k-ohm load

at less than 0.5% THD

(1 kHz)

[Output Voltage: ]

[S-01, S-02, S-03 ]

6. 3V (+16 dBv)

6.3 V (+16 dBv)

6.3V (+16 dBv)

6.3V (+16 dBv)

6.3 V (+16 dBv)

4.7V

(+13.4

(-6

dBv)

dBv) 0.5%

into 600-ohm load

0.5V

1 V peak to peak

1 V peak to peak

THD

Frequency

Response

±1dB

25~20,000 Hz

20~20,000 H z

RIAA

Equalized

20~20,000 H z

20~20,000 H z

20~20,000 H z

500~20,000 Hz
Low-cut 25 0 H z

30~20,000 H z

Noise Level

[equivelent]

[ Input noise]
[ or S/N ]

—126 dBm
200 ohms

terminated

S/ N 70dB

S/N 70 dB

S/N 90 dB

———

S/N 80 dB

S/N 80 dB
S/N 80 dB

S/N 80 dB

Signal

Muting

Level

———

60 dB

60 dB

———

60 dB

———

60 dB

———

60 dB

———

60 dB

Remote volume

control range

[use 10k ohms]

[potentiometer]

———

0~— 60 dB

———

0~—60dB

0~—60

dB

Controls

[pre-

settable]

1-Low

cut

1-High c u t

1-Gain

1-Low

cut

1-Gain

1-Low

cut

1-Gain

1-Gain

1-Gain

1- Sensitivity

1-Mute

1-Gain

1-Output
1-Output

1-Output

Weight

105 gr

100 gr

105 gr

100 gr

95 gr

105 gr

60 gr
50 gr

55 gr

70 gr

75 gr
65 gr
90 gr

95 gr
90 gr
95 gr

95 gr

100 gr

100 gr

55 gr

60 gr
70 gr

(max.)

(3.71

(3.53

(3.70

(3.53

(3.35

(3.70

(2.12
(1.76

(1.94

(2.47

(2.65
(2.29
(3.17

(3.35
(3.17
(3.35

(3.35

(3.53

(3.53

(1.94

(2.12
(2.47

oz)

oz)

oz)

oz)

oz)

oz)

oz)
oz)

oz)

oz)

oz)
oz)
oz)

oz)
oz)
oz)

oz)

oz)

oz)

oz)

oz)

oz)

H-01F

H-02F

X-01F

X-11F

B-01F

B-11F

L-01F

H-01M

H-02M

T-01M

Connector

X-01P

L-01P

T-01P

E-01R

-11R

X-01R

-11R

H-02S

E-01S

X-01S

-11S

X-21S

B-01S

L-01S
L-11S

L-41S

I-01S

T-01S

S-01S

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 th e gain as low as possible, the re by ,

noise can be reduced, and the maximum

permissible inp ut 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 FI LT ER

CONTROL

330Hz, 6dB/oct

(max. attenuation)

MUTE DELAY

CONTROL (I-01S)

HIGH-CUT FIL TER

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 to ne quality. With low-cut,

tone beco mes 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 ti me.

This provides flat characteristics at full

CW position and attenuation in high
frequency by turning CCW. Adjust it to
obtain proper tone quality. With high-

cut, to n e becomes soft.

SPECIFICATIONS IN COMMON

Load impedance

Mounting

Dimensions in mm (inches)

: 10k-ohms

: Card-edge connector

: 78(3.07)x35(1.38)x88(3.46)

(H) x (W) x (D)

— 9 —

TOA NEW 900 SERIES

Block Diagrams (Plug-in Modules)

H-01 Series

H-21S

H-31S

H-02 Series

H-22S

H-32S

B-01 Series

B-11 Series

L-01 Series

L-11S

L-41S

T-01 Series

H-03 Series

E-01 Series

E-11 Series

X-01 Series

X-11 Series

X-21S

S-01S

S-02S

S-03S

I-01S

— 10 —

Operation

and

Connections

(Plug-in Modules)

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)

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 swtich 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 wit h 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

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)

It is operated by closing the remote

switch.

S-02 (YELP AND BUZZER)

Each signal is generated by closing cor-

responding remote 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.

S-03 (ONE-TONE CHIME AND CONTINUOUS ONE-TONE
CHIME)

CONNECTIONS

By closing the remote switch, chime

sounds once.

By closing the remote switch, one-tone

chime sounds continuously during the

closure of the switch

— 11 —

TOA NEW 900 SERIES

I-01S (BALANCED PAGING INPUT MODULE)

This module is used for connecting TOA intercom Systems (EXES)

for paging. By connecting this module to the exchange in place of

an intercom station, paging is possible. It is provided with a pre­settable gain control. The I-01S is applicable to the TOA EXES­1000, EXES-5000 and EX-16 Intercom Systems.

CONNECTIONS

LMU (Line Modem Unit)

This unit is composed of a modulator to receive signals from

stations, a demodulator to send signals to the station and a scanning

circuit.
Summary Specifications of R and T Lines

R-line: Approx. 9mA DC plus audio signals of +30dBm m ax.

T-line: Approx. 9mA DC

HOW TO

Paging is possible from other station by dialing the station number

assigned to this module. To prevent a calling tone from being
sounded through the paging speaker, the module is designed to
override paging output during a period of time that the calling tone
signal is transmitted. The length of time to mute the paging output

is adjustable between zero and three seconds. During paging,
background music (the input signal fed to E -11, X-11, L-11 or B-11

module) is muted.

USE:

Operational Accessories

Rack-mounting Brackets

MB-931A MB-921A

A-906A

A-912A
P-906A
P-912A

P-924

(Silver)

M-900A
A-903A

Perforated Panel

(Silver)

PF-911

Volume Control Cover

— 12 —

Schematic A-90 3A

— 13 —

TOA NEW 900

SERIES

Schematic A-906A

— 14 —

Schematic A-912A