null  null
Operation Instruction Manual
TOA 900 SERIES
POWER AMPLIFIER
Features
1
2
3
4
5
6
7
8
Wide frequency response; 20 — 20,000 Hz, ±1dB
Low distortion and noise level
Excellent output regulation
A full range of plug-in modules
Self-protecting circuitry design
Varied output impedances; 4 and 8 ohms, 25 and 70 volts
Input level switch (selectable 1,000mV/100mV)
Portable or rack-mounting type
Toa Electric Co., Ltd.
KOBE, JAPAN
P-924A
General Descriptions
The TOA P-924A Power Amplifier delivers up to 240 watts of power
at less than 0.5% total harmonic distortion (THD) from 20 to
20,000 Hz (transformerless 4-ohm output). The P-924A has a highimpedance 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 M-01 series, M-03 series, M-51 series and M-61 series Microphone Preamplifiers, R-01 Mag. Phono Preamplifier, the U-01 series,
U-21 series and U-61 series Auxiliary Preamplifiers for high-level
sources, the B-01 series Bridging Transformers for bridging highimpedance lines, the L-01 series Line Matching Transformers 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.
The P-924A has a low-cut switch for 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 distribution
outlets.
With plug-in modules, the TOA P-924A Power Amplifier may be
used as a pre/power amplifier.
The P-924A can be rack mounted by using the MB-931A Rackmounting Bracket accessory. The PF-911 Perforated Panel (1.73
inches, 1 rack unit) accessory provides suitable ventilation, finished
in color to match the P-924A.
133-02-907-70
Printed in Japan
Rear Panel Controls and Features
Front Panel Controls and Features
Item
Name
1
POWER
ON-OFF
SWITCH
Applies line power. Two-position
pushbutton switch for on-off modes.
2
METER
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.
3
4
5
INPUT
VOLUME
CONTROL
Adjust gain of INPUT.
PROTECTION
INDICATOR
(RED)
This LED indicator comes on and goes
out in about 5 seconds after the power
switch is turned on.
If the LED indicator remains lit
indicating that a muting relay is not
activated, turn the power switch off
after disconnecting the speaker line
and turn it on again. As a result,
1. if the LED indicator goes out in
about 5 seconds, the speaker line
may be short-circuited or
overloaded.
Check the speaker line.
2. unless the LED indicator still goes
out, abnormality has occurred in the
power amplifier stage.
Check the power amplifier stage.
NORMAL
INDICATOR
(GREEN)
Item
Function/Description
Name
Function /Description
1
AC POWER
SUPPLY
CORD
Connects to power source.
2
AC OUTLET
(Unswitched)
Provides AC power for auxiliary equipment with power consumption of up to
500W.
3
AC FUSE
Protects amplifier from excessive current
drain. Replace only with same type fuse.
4
DC FUSE (-)
Refer to qualified service personnel if
fuse blows repeatedly.
5
DC FUSE (+)
6
OUTPUT
TERMINALS
Connect to speakers.
7
MODULE
INPUT
PORT
Accepts PLUG-IN MODULES which are
optionally available. Module selection is
determined by application.
8
LOW-CUT
SWITCH
Cuts off unnecessary low frequency.
9
INPUT
LEVEL
SWITCH
Selects input sensitivity. Place in "1V
(0dBv)" position when normally used
as a power amplifier.
AC FUSE
DC FUSE (-)
DC FUSE (+)
250V 7A
250V 8A
250V 8A
Note: The position of INPUT-LEVEL
SWITCH should be changed according to
modules used or equipment connected to
DIRECT INPUT TERMINAL.
Lights up when the amplifier is
normally working.
—1—
10
DIRECT
INPUT
TERMINAL
Connects directly to external equipment
without using modules. Unbalanced
10k ohms.
11
EARTH
TERMINAL
Normally connects to a record player's
ground.
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 modules. This terminal is directly connected with
a potentiometer inside.
(2) Plug-in module input
Select the desired modules according to application.
Plug-in Modules and Input Level SW Setting
Model
Plug-in Modules
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 modules used
or the equipment connected to DIRECT
INPUT TERMINAL.
When the P-924A is used in combination
with a mixer preamplifier or serves as an
incremental power amplifier, normally
place INPUT LEVEL SWITCH in "1V
(0dBv)" position.
No.
Input level SW
Setting
1V
(0dBV)
100mV
(—20dBV)
—
Balanced low impedance microphone preamp. module
(with presettable low-cut filter, high-cut filter and gain
controls)
Remote Volume
control
Voice Gate
Compressor
M-61
Unbalanced high impedance microphone preamp module
(with presettable low-cut filter, high-cut filter and gain
controls)
-
M-03
Equalized mag phono preamp module
(with presettable gain control)
-
R-01
—
Unbalanced high impedance auxiliary preamp. module
(with presettable gain control)
Remote Volume
control
Compressor
Balanced 10k
bridging transformer module
Balanced 600
bridging transformer module
Signal tone generator module
(with presettable output level control)
B-01
L-01
1kHz Sine Wave
S-01
Yelp and buzzer
S-02
One-tone chime and
continuous one-tone
chime
S-03
*See PLUG-IN MODULES for detail.
Output Connections P-924A
25V and 70V.
The speaker outputs of the amplifier are 4
8
Connect speakers to one of these outputs.
Class 2 wiring may be used.
25V and 70V via the output
Since these outputs consist of 8
the
transformer (matching transformer) and direct output of 4
connecting method differs in each case. See the following diagrams.
Note: Impedances indicated below imply total speaker system
(load) impedance.
25V
When connecting speakers to any one of the outputs of 8
or 70V (BALANCED TRANSFORMER OUTPUT);
Note:
In this case, the LOW-CUT SWITCH should be "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 LOW-CUT
SWITCH in "CUT" position
<P-924A>
When connecting speakers to the 4
DIRECT OUTPUT);
<P-924A>
—2—
output. (UNBLANCED
Rack Mounting
Installation
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.
To mount the amplifier in a standard 19-inch equipment rack, use
the MB-931A Rack-mounting Bracket accessory.
Remove 4 screws securing case.
Operation
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.
MB-931A
(Silver)
(OPTION)
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.
Fix the MB-931A with attached 4 screws.
The length of the screws should not
exceed 12mm (1/2 inches).
Perforated Panel
PF-911 (OPTION)
(Silver)
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.
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.
Servicing
Continuous signals
When the power amplifier is used in combination with a mixer preamplifier, adjust the total gain at the mixer preamplifier with the
gain setting of the power amplifier at maximum.
• 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.
—3—
Specifications
P-924A
Power amplifier
Type
Output
(D ) 240W RMS
(T ) 220W RMS
Power Band Width
( D ) 20-20,000
( T ) 50-20,000
H z , 0.5% T H D
H z , 0.5% T H D
(D) 20 -20,000 Hz,±1 dB
(T ) 2 0 - 15,000 Hz,±1 dB
Frequency Response
( T ) 2 0 -2 0 ,0 0 0 H z ,-3dB
0.01% at 1 kHz, rated output
Total Harmonic Distortion
inputs
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 Sensitivity/Impedance
Input Port
Direct Input
: 100 mV or 1 ,000 mV (Switchable)/10k ohms
: 100 mV or 1 ,000 mV (Switchable)/10k ohms
Outputs
(D) = Direct
(T) = Transformer
Output Regulation (1 kHz)
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 : 105 dB
Input level switch in —20 dBv (100 mV) position : 90 dB
Signal to Noise Ratio
(Band Pass20 — 20,000 Hz)
1
1
1
1
Controls
Indicator
Protection
Input gain control
Input level switch
Power ON/OFF switch
Low-cut switch (60 Hz, 6 dB/octave)
1 Illuminated VU meter, 2 LED for protection circuit
Self-protection, with 2 AC fuses (1 inside) and 2 DC fuses
Card-edge connector and screw-terminal strip
Screw-terminal strip
3-pin grounding type
SJT, 3-prong type
Inputs
Output
AC output
AC power cord/plut
Connectors
Power Consumption
AC 120 volts, 60 Hz, 3A
Temperature Range
Dimensions in mm (inches)
(high) x (wide) x (deep)
-10°C to +60°C (12°F to 140°F)
150.5 (5.92") x 420 (16.54") x 333 (13.11")
Rack-mounting space size "3U" (5.21")
Weight (without input modules)
19.5kg (43 Ibs.)
Silver
Color_______________
Other Features
Output disconnected for approx. 5 sec. after switching power on.
Specifications are subject to change without notice.
Block Diagram P-924A
—4—
Plug-in Modules
(OPTION)
Balanced Connection
MODEL
Connection
M-01 series M-11
M-51 series M-21
M-61 series
B-01 Series B-11, L-01
Series L-11, L-41, T-01
PLUG-CONNECTION
Input, Output Connection
Unbalanced Connection
U-01 series
U-11 series
U-12
U-21
U-61
Input, Output Connection
T-02
M-03
R-01
CANNON XLR-3-12 (Male) type CANNON XLR-3-12 (Male) type
CANNON
XLR-3-11 (Female) type
CANNON
XLR-3-11 (Female) type
Phone Plug (Double Pole)
Phone Plug (Single Pole)
RCA Phono Jack
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, POWER AMPLIFIERS P-906A, P-912A, P924A, and IN-WALL AMPLIFIERS W-906A, W-912A. Owing to wide
selection of types of connectors can also meet the needs of equipment
to be connected. MICROPHONE PREAMPLIFIER M-01 series, M-51
series, M-61 series, M-03, M-11 and M-21 incorporates controls for
high-cut, low-cut and gain. A gain cotrol is built in MAG. PHONO
PREAMPLIFIERS R-01, and AUXILIARY PREAMPLIFIERS U-01 series,
U-11 series, U-12, U-21 and U-61, LINE OUTPUT T-01 and AUX INPUTLINE OUTPUT T-02.
M-61 and U-61 are built-in compressor circuit to protect the output
level from distortion as a result of excessive input and keeps it constant.
M-51 series is built-in voice gate circuit to be automatically activated by
presence of signal.
U-12 can adjust mute level.
T-01 series is an output module with transformer, serving as a line output for recording, etc...
A group of special signal generating modules is also available for
catching-attention before announcement and testing within the total
systems. ALL PLUG-IN MODULES have handles on their front for easy
insertion and removal.
FEATURES
1. Wide dynamic range
2. Low noise and distortion
3. Wide frequency response
4. Built-in remote volume control circuit (M-21)
5. Built-in remote master volume or remote volume control circuit. (U-21)
6. 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 U-11.)
7. Built in muting circuit to deliver or mute its output signal when MUTE
TERMINAL is grounded. (M-11)
8. Built-in signal activated muting function (L-41)
9. Presettable gain control (except for B-01, B-11, L-01 and L-11)
10. Microphone modules furnished with tone controls (M-01, M-11, M-21,
M-51, M-61, and M-03)
11. Built-in voice gate circuit (to be activated by input signals.) (M-51 series.)
12. All the microphone modules (except M-03) come with phantom powering capability.
13. Built-in compressor circuit (M-61, U-61)
14. Built-in variable muting circuit to adjust the muting level. (U-12)
—5—
TOA 900 SERIES
Plug-in Modules
Specifications
Applications
Module
Types
Source
Impedance
FRONT PANEL CONTROLS AND FEATURES
inpu t Sensitivity
for Rated Output
(100mV )
GAIN
Connector
Max. Befor e Clip
int o 10k-ohm s toa d
as less than 0,5% THD
(1kHz)
outpu t voltag e
S-01, S-02, S-03
Frequenc y
Response
±1dB
Noise level
equivalen t
input nois e
Signal
or S/N
Level
GAIN CONTROL
Modules with built-in controls are provided in the following six types.
THRESHOLD
(M-61)
OUTPUT GAIN
(T-02)
NOMINAL POSITION
MARK
LOW-CUT FILTER
CONTROL
330Hz, 6dB/oct
(max. attenuation)
MUTE LEVEL
(U-12)
INPUT GAIN
(T-02)
— 6 —
Remote volume
control range
Use 10K ohms
potentiometer
Compress.
Range
[Threshold ]
Power
Requirement
[24V DC]
This adjusts gam. Turn clockwise (CW) to
increase and counter-clockwise (CCW) to
reduce gam
Set the gam as low as possible, thereby,
noise can be reduced, and the maximum
permissible input level is raised.
This adjusts threshold level of compressor.
Turn clockwise (CW) to reduce threshold
level (to activate the compressor with lower input signal level).
This adjusts gam of the line output. Turn
clockwise (CW) to increase and counterclockwise (CCW) to reduce gam regardless
of setting position of the input gam adjust
knob.
The left figure shows nominal setting of controls.
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 level. Turn clockwise
(CW) to increase mute level (to be muted
excessively) and counterclockwise (CCW)
to reduce mute level.
This adjusts input gam from AUX. Turn
clockwise (CW) to increase gam and counterclockwise (CCW) to reduce.
Control s
[Presettable]
Weight
(max.)
HIGH-CUT FILTER
CONTROL
4.2kHz, 6dB/oct
(max. attenuation)
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, tone becomes
soft.
SENSITIVITY
(M-51)
This adjusts sensitivity for voice gate.Turn
clockwise (CW) to increase sensitivity (to
open the gate at full CW position regardless of any input level) and counterclockwise (CCW) to reduce sensitivity.
SPECIFICATIONS IN COMMON
Load impedance
Mounting
Dimensions in mm (inches)
(H) x (W) x (D)
— 7 —
10k-ohms
Card-edge connector
78(3.07)x35(1.38)x88(3.46)
TOA 900 SERIES
Operation and Connections
Plug-in Modules
(Plug-in Modules)
"Jumper Wire Setting"
S-01 (1 ,000Hz SINE WAVE)
M-01, 11, 21, 51, 61
CONNECTIONS
It is operated by closing the remote
switch.
All the microphone modules come with phantom powering capability. I
not desired, cut J1 on the board.
Remote switch
U-21
Cut J2 on the board to use as a remote master volume control unit
Leave J2 on to use as a remote-control AUX module.
U-61
Cut J2 on the board to use as a compressor unit which goes between
PREAMP OUT and POWER AMP IN (LINK IN/OUT).
S-02 (YELP AND BUZZER)
CONNECTIONS
Yelp signal
Remote switch
M-11
Either (both) J3 or (and) J4 is (are) to be cut for a proper operation.
Refer to the table below.
J4
Function
on
on
No output signal
cut
on
Normally "Off", becomes "On" when muting
terminals are closed.
on
cut
Normally "On", becomes "Off" when muting
terminals are closed.
cut
cut
Works as a regular microphone input module.
^Z: Impedance
Each signal is generated by closing corresponding remote switches.
Buzzer signal
J3
Mute: Normally "On", becomes "Off" when muting
__ terminals are closed.
Mute: Normally "Off", becomes "On" when muting
terminals are closed.
Remote switch
S-03 (ONE-TONE
CHIME)
CHIME
AND
CONTINUOUS ONE-TONE
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.
Accessories
Rack-mounting Brackets
Perforated Panel
(Silver)
(Silver)
Volume Control Cover
Block Diagrams (Plug-in Modules)
— 10 —
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement