Toa M-9000, M-900A Operation & Instruction Manual
Operation Instruction Manual
TOA NEW 900 SERIES
MIXER PREAMPLIFIER
Features
1 6-channel mixer preamplifier
2 Wide frequency response; 20 — 20,000Hz, ± 1dB
3 Low distortion and noise
4 Parallel operation of two mixer preamplifiers
5 Headphone output
6 Bass and treble controls
7 Tone defeat switch
8 Output on-off switch
9 VU meter range switch (selectable 4dBm/18dBm)
10 A full range of plug-in modules
11 Balanced and transformer-isolated output of 150/600 ohms
12 Portable or rack-mounting type
M-900A
General Description
The TOA M-900A Mixer Preamplifier controls and mixes up to six
independent input signals and delivers up to +20dBm of output
power. Optional plug-in modules are a vai lab le for use with t he M900A to provide versatility for a wide choice of operating applications. Edge connectors in the rear of the unit permit selection from
a wi de range of 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 for magnetic phono inputs, 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, the 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 Generators for generating attention-getting signals
and 1kHz sine wave for testing within the total system. Sources fed
to
particular
at MUTE TERMINAL on the rear. To perform this function,
Module E-11, X-11 series or B-11 series is required.
The TOA M-900A Mixer Preamplifier has a balanced and transformerisolated output for operation with 600-ohm or 150-ohm
loads.
Other features include a tone defeat switch, an output on/off
switch, connections for parallel coupling of another M-900A or
Mixer Power Amplifiers A-903A, A-906A or A-912A, and monitoring by visual and/or audio means.
input
module
accessories
are
muted
by
short-circuiting
Toa Electric Co., Ltd.
KOBE, JAPAN
133-02-736-1
Printed in Japan
Front Panel Controls and Features
Rear Panel Controls and Features
Item
POWER ON-OFF
1
SWITCH
METER
2
INPUT VOLUME
3
CONTROLS
BASS CONTROL
4
Name
Adjust gain of INPUT #1-#6
Turn clockwise (CW) to boost and
Function/Description
Appli es line power. Two-position
pushbutton switch for on-off modes.
Indicates the output level of the
amplifier. At rated output, it shows
0 VU (continuous sine-wave signal
input).
When power is turned on, meter
illuminates.
respectively.
Adjust bass response.
counterclockwise (CCW) to
attenuate the bass response. Tone is
flat at center.
TREBLE
5
CONTROL
TONE SWITCH
6
MASTER
7
VOLUME
CONTROL
OUTPUT SWITCH
8
Adjust treble response.
Turn CW to boost and CCW to
attenuate the treble response. To ne is
flat at center.
Selects IN/DEFEAT of the BASS and
TRE BL E CONTROLS. When this
button is depressed
and TREBLE Controls are active.
When pressed again
become inactive to make tone fl at .
(DEFEAT)
Adjusts overall gain of unit.
This is an output ON/OFF switch.
When pressed
obtained at the output terminal.
When pressed again
signal is obtained.
HEADPHONE
9
JACK
HEADPHONE
10
VOLUME
CONTROL
VU RANGE
11
SWITCH
Usually
set the
amplifier's rated output is +4dBm.
Place it in "18dBm" position when more output is
provided.
Connects to headphones with
impedance of more than 8
Adjust the volume for headphones.
Turn CW to increase.
Selects meter-sensitivity.
When set to "4dBm" position, the
meter shows 0 VU if the output level
of amplifier is +4dBm. When set to
"18dBm," it shows 0 VU if the
output level is +18dBm.
switch
to
"4dBm"
position,
the BASS
they
output signal is
no output
since
the
Item
1
AC POWER
SUPPLY CORD
AC OUTLET
2
(Unswitched)
AC FUSE
3
(250V 0.3A)
OUTPUT
4
TERMINALS
MODULE INPUT
5
PORTS
AUX O UT
6
7
BRIDGING
INPUT/OUTPUT
MUTE
8
TERMINAL
EARTH
9
TERMINAL
Name
Function/Description
Connects to power source.
Provides AC power for auxiliary
equipment with power consump tio n
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.
Connect to power a mplifier(s).
Accept PLUG-IN MODULES which
are optionally available. Choose the
desired modules according to
application.
Serves as a sub-output for connecting
other equipment having input
impedance of more than 10k
as a tape recorder.
This terminal is used as a mixing bus.
Mixing is achieved when the similar
terminal of another amplifier is
connected to this terminal.
such
The output level take n 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 10k
higher.
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.
or
— 1 —
Input Connections
Output Connections
This amplifier 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 rai ls, 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
preamp module (w ith pr esettable low-cut
filter, high-cut filter and gain controls)
Balanced low impedance microphone
H-01,
H-21,
H-31
H-02,H-22, H -32
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)
Balanced 10k
Balanced 600
transformer module
bridging transformer module
line matching
X-01,
L-01,
E-01 , E-11
X-11,
X-21
B-01,
B-11
L-11,
L-41
Balanced paging input module
(with presettable gain control and MUTE Delay)
Balanced 600
(with presettable gai n control)
Signal tone generator module
(with presettable output level control)
line output module
1 kHz sine wave
Yelp and buzzer
One-tone chime and continuous one-tone chime
T-01
S-01
S-02
S-03
I-01
Connect power amplifier(s) to the output terminal of M-900A.
•
Select 600
mina l, to match the input impedance of amplifier(s).
600-ohm Connection
4
3
2
1
GND
150-ohm Connection
4
3
2
1
GND
AUX
OUT
•
For this connection, use a Phone Plug (Double pole) with two-wire
shielded cable.
or 150
Strap terminals 2 and 3 .
Strap terminals 1 and 2 , 3 and 4 .
connection, provided at the output ter-
Hot
Common
Earth
Hot
Common
Earth
Hot
Common
Earth
External equipment such as
tape recorders, etc.
*W
ith 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 i ncorporate muting functions. If a switch
is connected to MUTE TERMINAL on the rear panel of the ampli-
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 extern al equipment.
*T-01 should be inserted only in INPUT PORT #5 or #6.
(See PLUG-IN MODULES for details)
— 2 —
Operation
Installation
When all connections are completed, turn power switch on. Then,
the meter is illuminated. Approximately 5 seconds after switching
power on, the M-900A comes into operation.
VOLUME CONTROL
Set VU RANGE SWITCH to "4dBm" position and place OUTPUT
SWITCH in "ON" position. While observing the deflection of the
meter, control each input volume and master volume controls to
obtain a proper output level.
The swinging range of the pointer on the meter is recommended to
be within the range as indicated in the drawing. Also, adjust gain
(volume control) of the connected power amplifier to obtain similar
readi ng on the meter of the power amplifier.
In connecting a power amplifier with lower gain, so that the
mixer preamplifier is required to be used with its higher output,
the VU RANGE SWITCH shall be set to 18dBm.
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.
Do not block cover ventilation holes.
•
The M-900A 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.
MONITOR
Monitoring is possible by the use of headphones.
Connect the headphones to HEADPHONE JACK, and adjust the
monitoring level by using the HEADPHONE VOLUME CONTROL.
OUTPUT ON/ OF F SWITCH
ON/OFF status of the output can be controlled by the OUTPUT
SWITCH, and output can be obtained at the output terminal and
auxiliary output ja ck after confirming the content of the signal by
monitoring with headphones.
— 3 —
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