Alto L-16 User Manual

Service
MODEL: L-12/16/20
www.altoproaudio.com
Version 2.0

Alto L-16 Specifications

General

Channels	16
Microphone Inputs	8
Line Inputs	8
Aux Sends	4
Phantom Power	Yes
Faders	16
Other Inputs	2
Main Outputs	2
Other Outputs	2
USB Interface	Yes
Type	Analog Mixer
EQ Bands	3-band
Effects	Built-in

Summary

Alto L12, L16, L20 Features

Channel Strips Features

Details the features of the input channel strips, including faders, EQ, and connectivity.

Master Section Features

Describes the master section capabilities, including DSP effects, graphic EQ, and outputs.

Technical Specifications

Input Channel Specifications

Details specifications for mono and stereo input channels, including frequency response and gain.

Impedance and Equalization Specs

Lists input/output impedance values and equalization band specifications.

DSP and Main Mix Specifications

Details DSP converter specs, effect types, and main mix/AUX send levels.

Power Supply Details

Main Voltage and Region Settings

Specifies AC input voltage ranges for different regions (USA, Europe, UK/Australia).

Power Consumption and Fuse Rating

Details power usage, fuse ratings for different voltage ranges, and main connection type.

Schematic Diagrams Overview

System Block Diagram

Provides a high-level overview of the audio signal flow through the device.

L12PU1 Schematic Diagrams

L12PU1(1/2) - Control Room, Aux Send, Main Insert

Details circuits for control room output, aux sends, and main insert.

L12PU1-2(2/2) - Aux Return, Main Out, Subwoofer Inserts

Details stereo aux return, balanced main output, and subwoofer insert circuits.

L12PU2 Schematic Diagrams

L12PU2-2 - Phones Output and Tape Connections

Details headphone output and tape interface circuitry.

L12MN2(1/5) Schematic Overview

Channel 1-4 Block Layout

Shows the block layout for channels 1 through 4.

L12MN2 Channel 1 Schematic

EQ, Pan, Level, Mute, and Aux Send Circuits

Details EQ, pan, level, mute, and aux send circuitry for channel 1.

L12MN2 Channel 2 Schematic

EQ, Pan, Level, Mute, and Aux Send Circuits

Details EQ, pan, level, mute, and aux send circuitry for channel 2.

L12MN2 Channel 3 Schematic

EQ, Pan, Level, Mute, and Aux Send Circuits

Details EQ, pan, level, mute, and aux send circuitry for channel 3.

L12MN2 Channel 4 Schematic

EQ, Pan, Level, Mute, and Aux Send Circuits

Details EQ, pan, level, mute, and aux send circuitry for channel 4.

L12MN1 Main Input Stage Schematics

Stereo Input Channel Schematics (CH5-CH12)

Details stereo input channel schematics for channels 5 through 12.

Other Input/Output and Aux Return Circuits

Covers other I/O interfaces and aux return paths.

Control Room Meter and DSP Sections

Shows control room meter and DSP block schematics.

CH5-8 Stereo Channel Schematic

EQ and Control Circuitry

Details EQ, pan, level, mute, and aux send circuits for stereo channels.

CH9-12 Stereo Channel Schematic

EQ and Control Circuitry

Details EQ, pan, level, mute, and aux send circuits for stereo channels 9-12.

Main Mix, Subwoofer, and EQ Circuits

Main Output and Subwoofer Signal Paths

Details main output and subwoofer signal paths, including 2TK to Mix.

9-Band Graphic Equalizer Circuit

Illustrates the implementation of the 9-band graphic equalizer.

Aux Return Schematic

Aux Return Signal Paths

Details the circuits for all auxiliary return paths (1-4).

Main Mix and Monitor Output Connections

Shows connections to main mix and monitor outputs, including DFX.

Aux Send Schematic

Aux Send Signal Paths

Details the circuits for all auxiliary send paths (1-4).

DFX Send Path

Shows the digital effects send path.

Control Room VU-Meter Schematic

Control Room Signal Routing and Metering

Details signal sources, routing, and VU meter circuitry for control room.

L12 DSP In/Out Section Schematic

Effects Processing and Interface Circuits

Details EFX processing, interface, and footswitch circuits.

Power Supply Board Schematic

AC Input, Transformer, and Phantom Power

Details AC input, transformer, and phantom power circuitry.

Voltage Regulation and Power Outputs

Shows regulated voltage rails and power outputs.

Digital Effect Board (CHEF) Schematic

Audio Converter and Memory ICs

Details audio converter and memory IC schematics.

Logic, Power, and Interface Circuits

Shows logic gates, power regulation, and interface components.

Wiring Configuration Diagram

Module Interconnection Schematics

Shows how different PCBs and modules connect within the system.

Power, DSP, and Lamp Connections

Details connections to power supply, DSP, and lamp.

Finished Product Test Procedure

Required Instruments and Initial Setup

Lists test equipment and initial setup steps.

Functional Testing Steps

Outlines the functional testing process for various inputs and outputs.

Input Signal Frequency Response Test

Describes testing the frequency response of line inputs.

EQ Frequency Response Curves

Presents frequency response curves for EQ adjustments.

Final Test Procedures and Remarks

Provides final test remarks, DSP testing, and sampling test steps.