Toa A-901A User Manual

3 Low distortion and noise level
4 Excellent output regulation
5 Bass and treble controls on Input #1 and Program Input
6 Incorporated muting circuit
7 Self-protecting circuitry design
8 A full range of plug-in modules
9 Varied output impedances; 4 and 8 ohms, 25 and 70 volts
10 Clipping indicator
11 Compactness and lightweight
12 Portable or rack-mounting type
The TOA A-901A Mixer Power Amplifier controls and mixes up to
three independent input signals. Producing 10 watts of power, the
A-901A has ideal flexibility for small sound reinforcement systems.
Optional accessory modules are available for use with the A-901 A to
provide versatility for a wide range of operating applications. Edge
connectors on the rear of the unit permit the selection of TOA plug-
in modules : The H-01 series, H-02 series and H-03 series Micro-
phone Preamplifiers, the E-01 Mag. Phono Preamplifier, the X-01
series Auxiliary Preamplifiers for high-level sources, the B-01 series
Bridging Transformers for bridging high-impedance 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, and the S-01, S-02 and S-03
Tone Signal Generators for generating attention-getting signals and
1kHz sine wave for testing within the total system. Other features
include a muting function. Sources fed to Program Input and
Input 1 are simultaneously muted by short-circuiting at MUTE
TERMINAL on the rear. Accordingly, Input 2 can have priority.
The TOA A-901 A Mixer Power Amplifier has transformer-
isolated 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-901 A can be rack mounted by using the MB-920 Rack-
mounting Bracket Accessory.
TOA Corporation
133-02-735-OA
Printed in Japan
2 Wide frequency response; 20 — 20,000 Hz, ±1dB
1 3-channel mixer power amplifier
TOA NEW 900 SERIES
MIXER POWER AMPLIFIER
Operation Instruction Manual
A-901A
General DescriptionFeatures

Toa A-901A Specifications

Power

output power	10 watts RMS
power consumption	30 watts
voltage	AC 120 volts, 60 Hz

Operating Environment

temperature range	-10°C to +60°C (12°F to 140°F)
frequency response	20—20, 000 Hz, ± 1 dB
signal-to-noise ratio	82 dB

Weight and Dimensions

height	3.98" (101 mm)
width	9.84" (250 mm)
depth	9.65" (245 mm)
weight	8.6 lbs (3.9 kg)

Summary

Connection and Operation Guide

Input Connections

Details how to connect plug-in modules and program sources to the amplifier's input ports.

Operation and Tone Adjustment

Guides on operating the amplifier, adjusting volume, and setting tone quality using controls.

Specifications

Technical Specifications

Comprehensive technical details including type, power, frequency response, inputs, outputs, and dimensions.

Plug-in Modules and Accessories

Module Compatibility

Lists TOA plug-in modules compatible with 900 Series amplifiers and their connection types.

Plug-in Module Specifications

Module Operation and Connections

Mute Module Operation

Explains the mute function of H-31/H-32 modules and how it affects input signals via remote switch.

Schematic Diagram

A-901A Main Circuit

Presents the detailed schematic diagram of the A-901A Mixer Power Amplifier's internal circuitry.