Focusrite OctoPre User Manual

ENGLISH
1
CONTENTS
CONTENTS.................................................................................................................1
IMPORTANT SAFETY INSTRUCTIONS..............................................................1
INTRODUCTION......................................................................................................2
REAR PANEL CONNECTIONS..............................................................................2
GETTING STARTED.................................................................................................3
TIPS FOR OBTAINING A GOOD QUALITY VOCAL SOUND.........................3
TIPS FOR OBTAINING A GOOD QUALITY ELECTRIC GUITAR SOUND..4
FACILITIES AND CONTROLS................................................................................4
DIGITAL OUTPUT OPTIONS .................................................................................6
DIGITAL OUTPUT FRONT PANEL CONTROLS...............................................6
DIGITAL OUTPUT REAR PANEL CONNECTIONS AND SWITCHES...........7
A BEGINNER’S GUIDE TO COMPRESSION .......................................................8
FREQUENTLY ASKED QUESTIONS.....................................................................9
TROUBLESHOOTING............................................................................................10
CONTACTING US...................................................................................................10
SPECIFICATIONS.....................................................................................................11
DISTRIBUTOR LIST................................................................................................60
IMPORTANT SAFETY INSTRUCTIONS
Please read all of these instructions and save them for future reference. Follow all warnings and
instructions marked on the unit.
• Do not obstruct air vents in the rear panel. Do not insert objects through any apertures.
• Do not use a damaged or frayed power cord.
• Unplug the unit before cleaning. Clean with a damp cloth only. Do not spill liquid on the
unit.
• Ensure adequate airflow around the unit to prevent overheating. We recommend
leaving a blank 1U panel above the unit to aid ventilation.
• Unplug the unit and refer servicing to qualified service personnel under the following
conditions: If the power cord or plug is damaged; if liquid has entered the unit; if the unit
has been dropped or the case damaged; if the unit does not operate normally or exhibits a
distinct change in performance. Adjust only those controls that are covered by the
operating instructions.
• Do not defeat the safety purpose of the polarised or grounding-type plug. A polarised plug
has two blades with one wider than the other. A grounding type plug has two blades and a
third grounding prong. The wider blade or the third prong is provided for your safety.
When the plug provided does not fit into your outlet, consult an electrician for
replacement of the obsolete outlet.
WARNING: THIS UNIT MUST BE EARTHED BY THE POWER CORD.
UNDER NO CIRCUMSTANCES SHOULD THE MAINS EARTH BE
DISCONNECTED FROM THE MAINS LEAD.
This unit is supplied pre-configured to operate only at the voltage indicated on the rear panel.
Ensure correct mains voltage is available and the correct fuse value is fitted before connecting to
the mains supply. To avoid the risk of fire, replace the mains fuse only with the correct value
fuse, as marked on the rear panel. The internal power supply unit contains no user serviceable
parts. Refer all servicing to a qualified service engineer, through the appropriate Focusrite dealer.
RACK VENTILATION: PLEASE ENSURE THE OCTOPRE IS PLACED
TOWARDS THE BOTTOM OF YOUR EQUIPMENT RACK, WITH
SUFFICIENT SPACE ABOVE AND BELOW FOR VENTILATION.

Focusrite OctoPre Specifications

General

Type	Microphone Preamplifier
Channels	8
Word Clock	Yes
Rack Spaces	1U
Phantom Power	Yes
A/D Resolution	24-bit
Analog Inputs	8 XLR
Analog Outputs	8 TRS
Digital Inputs	ADAT Optical
Digital Outputs	ADAT Optical
Clock I/O	BNC
Mounting Option	Rack
Frequency Response	20Hz - 20kHz
THD+N	<0.001%

Summary

Important Safety Instructions

Earthing Warning

Crucial warning about the unit's earth connection via the power cord and not disconnecting the mains earth.

Voltage and Fuse Precautions

Advises checking mains voltage and fuse value, recommending qualified service for repairs.

Rack Ventilation Guidance

Provides guidance on rack placement for optimal airflow and ventilation of the unit.

OctoPre Introduction

Rear Panel Connections

Getting Started Guide

Vocal Sound Tips

Microphone Positioning for Vocals

Explains optimal microphone placement and the use of pop shields and high-pass filters for vocals.

Using Dynamics for Vocal Consistency

Details how to use the dynamics control to achieve consistent vocal levels and compression.

Electric Guitar Sound Tips

Effects Pedal Connectivity

Explains how to connect external effects pedals between the guitar and the OctoPre's instrument input.

Dynamics for Guitar Sustain

Advises on using compression to even out guitar volume and add sustain.

Facilities and Controls Overview

Power Button Function

Explains the power button function and recommends powering up before connecting other equipment.

Instrument Input Details

Details the high-impedance 1/4" jack input for guitars and basses.

Instrument Input Switch

Describes the switch that routes the instrument input to the channel, bypassing MIC/LINE.

Phase Reverse Switch (Ch 1&2)

Explains the phase reverse function for correcting phase problems with multiple microphones.

Line Input Switch

Controls the selection between rear panel MIC and LINE inputs.

+48V Phantom Power Switch

Activates phantom power for condenser microphones connected to the MIC input.

Level Control and Signal LEDs

Adjusts the signal level for the channel and indicates signal presence with SIG/O/L LEDs.

Dynamics Control and Compression

Explains the DYNAMICS control for compression and the 'brick-wall' limiter function.

Digital Output Options Explained

ADATM Interface Card

Describes the ADAT interface card, its output connectors, and sample rate handling.

AES/SPDIF/ADATM Interface Card

Details the AES/SPDIF/ADAT interface card, its outputs, and conversion cable requirements.

Digital Output Front Panel Controls

Clock Select Control

Describes the switch used to select the digital output sample rate and its corresponding LEDs.

Dither Bit Depth Selection

Explains the switch for selecting digital output bit depth (24, 20, 16-bit).

Lock LED Indicator

Indicates when the unit is synchronised to an external word clock signal.

Digital Output Rear Panel Connections

External Sync and Lightpipe

Details EXT SYNC connectors/switches for external clocking and ADAT lightpipe outputs.

SPDIF and AES/SPDIF Configuration

Covers SPDIF switch and AES/SPDIF connector for digital output format selection.

Beginner's Guide to Compression

Frequently Asked Questions

Class A Amplifier Design

Explains the benefits of the Class A design for linear audio representation.

Heat Generation

Addresses concerns about the unit getting hot, attributing it to Class A circuitry.

24-bit/96kHz Specification

Details the importance of high sample rate and bit depth for accurate digital audio transfer.

Digital Board Retrofitting

Explains that digital boards can be retro-fitted by the customer.

Troubleshooting Common Issues

No LEDs Illuminate

Troubleshoots issues where no LEDs are lit, checking power and voltage settings.

No Output (MIC Input)

Guides on diagnosing no output when using the microphone input.

No Output (LINE Input)

Guides on diagnosing no output when using the line input.

No Output (Instrument Input)

Guides on diagnosing no output when using the instrument input.

Dynamics Control Ineffective

Troubleshoots why the dynamics control may seem to have no effect.

Specifications and Performance

Input and Connector Specifications

Details input types, impedance, nominal levels, and connector types.

Front Panel Controls Summary

Lists the functions and ranges of the front panel controls.

Metering and Output Specifications

Details metering indicators, analogue output, and digital output information.

Performance Metrics

Provides technical performance data including THD, noise, EIN, and frequency response.