TOA M-900MK2 UL Users Manual

TOA 900 SERIES II

Operating Instructions

MIXER PREAMPLIFIER

M-900MK2

THE LIGHTNING FLASH WITH ARROWHEAD WITHIN A TRIANGLE IS INTENDED TO TELL THE USER THAT PARTS INSIDE THE PRODUCT AR E A RISK OF ELECTRIC SHOCK TO PERSONS.

TO REDUCE THE RISK OF ELECTRICAL SHOCK, DO NOT REMOVE COVER.

NO USER SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED

SERVICE PERSONNEL.

Please follow the instructions in this manual to obtain the optimum results from this unit. We also recommend that you keep this manual handy for future reference.

THE EXCLAMATION POINT WITHIN A TRIANGLE IS INTENDED TO TELL THE USER THAT IMPORTANT OPERATING AND SERVICING INSTRUCTIONS ARE IN THE PAPERS WITH THE APPLIANCE.

TOA Corporation

Contents

General description

Features Nomenclature

Front panel

Rear panel

Input connections

Output connections

Muting and remote volume control connection

Rack mounting

Operation

Volume adjustment

Tone control adjustment Installation Servicing Specifications

Appearance

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General Description

The TOA M-900MK2 Mixer Preamplifier controls and mixes up to eight independent input signals and

delivers up to +20 dBm of output power. Optional plug-in modules are available for use with the M-900MK2 to

provide versatility for a wide choice of operating applications. Edge connectors on the rear of the unit permit

the selection from a wide range of the TOA plug-in modules. The mixer preamplifier has a balanced and transformer-isolated output for operation with 600 ohms or 150

ohms loads.

Other features include a tone defeat switch, muting functions, remote master volume control and connections

for another mixer preamplifier or mixer power amplifiers A-903MK2, A-906MK2 and A-912MK2.

Features

1. 8-channel mixer preamplifier

2. Wide frequency response : 20~20,000 Hz ± 1 dB

3. Low distortion and noise level

4. Parallel operation of two mixer preamplifiers.

5. Bass and Treble controls

6. Tone defeat switch

7. Remote master volume control

8. A full range of plug-in modules

9. Balanced and transformer-isolated output of 150/600 ohms.

10. Portable or rack mounting type

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Nomenclature

< Front Panel >

Power Switch

Applies line power. Two-position push button

switch for on/off modes.

Power Indicator LED

Green LED lights when the power is switched "ON".

Signal Indicator LED

Green LED lights when more than —30 dB signal level is fed to the inputs by means of the input

and master volume controls.

Normal Indicator LED

Yellow LED lights when fed to the proper signal level.

Peak Indicator LED

Red LED lights when amplifier approaches clipping level. If steady lit, the input level control

should be turned down until the LED flashes only

intermittently.

Input Volume Controls

Adjust gain of input #1 ~ #8 respectively.

Bass Control

Modifies bass response. Turn clockwise to boost,

counter-clockwise to attenuate the bass response. Tone is flat at center.

Treble Control

Modifies treble response. Turn clockwise to boost, counter-clockwise to attenuate the treble response. Tone is flat at center.

Tone Switch

Selects ON/OFF of the BASS and TREBLE controls. When slided to OFF, BASS and TREBLE controls are active. When slided to ON,

they become inactive to make tone flat.

Master Volume Control

Adjusts overall gain of the unit.

Protection Indicator LED

Remains lit for about 5 seconds after power

switch is turned ON.

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