Toa A-903MK2 - User Manual

900 series
MIXER POWER AMPLIFIERS
A-903MK2
A-906MK2
A-912MK2
9
00
SERIES
AMPL
IFIER
A
–
903
MK
2
T
O
N
E
D
E
F
E
A
T
OFF
ON
L
O
W
C
U
T
OFF ON
S
I
G
N
A
L
N
O
R
M
A
L
PR
O
T
E
CT
O
N
OF
F
P
E
A
K
P
O
W
E
R
M
A
S
T
ER
IN
P
U
T
8
IN
P
U
T
7
IN
P
U
T 6
IN
P
U
T
5
I
N
P
U
T
4
IN
P
U
T
3
IN
P
U
T
2
T
R
E
B
L
E
IN
P
U
T
1
B
A
S
S
OPERATING INSTRUCTIONS
Thank you for purchasing TOA's 900 Series Mixer Power Amplifier.
Please carefully follow the instructions in this manual to ensure long, trouble-free use of your equipment.
This figure represents the A-903MK2.
TABLE OF CONTENTS
1. IMPORTANT SAFETY INSTRUCTIONS ..... 2
2. SAFETY PRECAUTIONS ............................ 3
3. GENERAL DESCRIPTION .......................... 5
4. FEATURES .................................................. 5
5. NOMENCLATURE AND FUNCTIONS ........ 6
6. INSTALLATION AND CONNECTIONS
6.1. Module Installation ................................ 8
6.2. Speaker Connections ............................ 9
6.3. Remote Control Connections .............. 11
7.
RACK MOUNTING BRACKET ATTACHMENT ... 12
8. OPERATION .............................................. 13
9. VOLUME CONTROL COVER ................... 13
10. DIMENSIONAL DIAGRAMS
10.1. A-903MK2 ......................................... 14
10.2. A-906MK2, A-912MK2 ...................... 14
11. SPECIFICATIONS
11.1. A-903MK2 ......................................... 15
11.2. A-906MK2, A-912MK2 ...................... 16

Summary

Important Safety Instructions

Safety Precautions

General Description

Features

Nomenclature and Functions

Installation and Connections

Module Installation

Explains the process of installing optional plug-in modules into the amplifier's input ports.

Speaker Connections

A-903 MK2: Speaker connection to transformer-balanced output

Specific instructions for connecting the A-903MK2 model to transformer-balanced speaker outputs.

A-903 MK2: Speaker connection to unbalanced DIRECT output

Specific instructions for connecting the A-903MK2 model to the unbalanced DIRECT output.

A-906 MK2 and A-912 MK2: Speaker connection to transformer-balanced output

Instructions for connecting A-906MK2/A-912MK2 models to transformer-balanced speaker outputs.

A-906 MK2 and A-912 MK2: Speaker connection to unbalanced DIRECT output

Instructions for connecting A-906MK2/A-912MK2 models to the unbalanced DIRECT output.

Remote Control Connections

Mute control connection

Details the wiring for the mute control function using external mute and ground terminals.

Remote volume control connection

Describes how to connect a potentiometer for remote master volume control on the front panel.

Rack Mounting Bracket Attachment

Operation

Volume Control Cover

Dimensional Diagrams

A-903 MK2

Dimensional diagrams specific to the A-903MK2 model, including width, height, and depth.

A-906 MK2, A-912 MK2

Dimensional diagrams for the A-906MK2 and A-912MK2 models, showing their physical dimensions.

Specifications

A-903 MK2

Detailed technical specifications for the A-903MK2 model, covering power, frequency, and inputs.

A-906 MK2, A-912 MK2

Detailed technical specifications for the A-906MK2 and A-912MK2 models, including power and frequency.

Toa A-903MK2 Specifications

General

Tone Control	Bass: ±10 dB at 100 Hz, Treble: ±10 dB at 10 kHz
Power Source	AC 120 V, 60 Hz
Frequency Response	20Hz - 20kHz (±1dB)
Total Harmonic Distortion	Less than 0.5%, 1 kHz, rated power
Input Sensitivity	Mic: -60 dB, Aux: -20 dB
Signal-to-Noise Ratio	60 dB or more
Input	Mic, Aux
Output	4-16 ohms
Input Impedance	MIC: 600Ω, AUX: 10 kΩ
Output Impedance	4-16 ohms
Phantom Power	Not supported