Focusrite Clarett Octopre User Guide

User Guide

Version 1.0

www.focusrite.com

TABLE OF CONTENTS

OVERVIEW..................................................................... 3

Introduction .................................................................3

Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Box Contents ................................................................4

Hardware Features ...........................................................4

Front Panel ....................................................................4

Rear Panel ....................................................................6

Using the Clarett OctoPre ......................................................8

Combo Inputs ..................................................................8

Pre-amp Gain ..................................................................8

Phantom Power ................................................................8

Line Outputs ...................................................................8

Digital Outputs .................................................................9

Digital Synchronisation ..........................................................9

Clarett OctoPre as Clock Source Master: ..........................................9

Clarett OctoPre as Clock Source Slave: ...........................................9

Digital Inputs .................................................................10

AIR mode.....................................................................10

Inserts .......................................................................10

ADAT-to-Line mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Example Setups.............................................................12

1. Clarett OctoPre with audio interface: OctoPre as clock source Master ................12

2. Clarett OctoPre with audio interface: audio interface as a clock source Master .........12

3. Clarett OctoPre with Clarett 8PreX – SMUX-II and SMUX-IV modes ...................13

4. Clarett OctoPre with analogue mixing desk.......................................13

5. Clarett OctoPre in ADAT > Line mode ...........................................14

6. Using Clarett OctoPre’s inserts to record drums ..................................15

CLARETT OCTOPRE TECHNICAL SPECIFICATIONS ..................................16

Performance Speciﬁcations ...................................................16

Physical and Electrical Characteristics ..........................................17

TROUBLESHOOTING ...........................................................18

OVERVIEW

Introduction

Thank you for purchasing a Clarett OctoPre, an eight channel mic-pre expansion unit incorporating high quality Clarett analogue pre-ampliﬁers with the unique Focusrite AIR function, plus send-andreturn insert points on each channel. As well as offering purely analogue operation for stand alone live use, the Clarett OctoPre includes both A-to-D and D-to-A conversion, providing a perfect solution for expanding your input and output capabilities via ADAT for recording.

This User Guide provides a detailed explanation of the hardware to help you achieve a thorough understanding of the product’s operational features. We recommend that you take the time to read through the Guide, whether you’re new to professional audio or a more experienced user, so that you are fully aware of all the possibilities the Clarett OctoPre has to offer.

If the User Guide sections do not provide the information you need, be sure to consult

https://support.focusrite.com, which contains a comprehensive collection of answers to common

technical support queries.

Features

The Clarett OctoPre is an eight-channel pre-ampliﬁer for use with microphone, line and instrument input signals. It converts the inputs into multi-channel, 24-bit digital audio at sample rates up to 192 kHz. Both analogue and digital outputs are provided: the digital outputs are in ADAT format on optical TOSLINK connectors, which can be easily routed to ADAT inputs on your studio recording system, or any other ADAT-equipped interface using optical cables. The Clarett OctoPre can transmit and receive eight channels of audio at sample rates of 44.1, 48, 88.2, or 96 kHz, or four channels at

176.4 or 192 kHz.

A switchable analogue INSERT function is provided on each input channel to permit the connection of external processors such as compressors or noise gates.

The OctoPre is an ideal “expansion” unit for adding eight more inputs to an existing audio interface such as other members of the Focusrite Clarett range.

The Clarett OctoPre is a bidirectional unit: it is also equipped with ADAT format digital inputs and balanced analogue outputs. It incorporates an ADAT-to-LINE mode, making it the perfect interface for routing tracks from your DAW to an analogue mixing console.

The Clarett OctoPre can be easily synchronised with other items of digital audio equipment in your studio, either as a slave to an external word clock signal, or by acting as the master clock source itself.

An important feature of all models in the Clarett range is the new design of analogue preampliﬁer. In addition to their class-leading dynamic range and ability to provide all the gain you’re ever likely to need, the circuitry now includes the Focusrite AIR function. Individually selectable on each channel, AIR subtly modiﬁes the pre-amp’s frequency response to model the impedance and resonance characteristics of Focusrite’s classic transformer-based ISA mic preamps. When recording with good quality microphones, you will notice an enhanced clarity and deﬁnition in the important mid frequency range, just where it is most needed for vocals and many acoustic instruments.

Box Contents

Along with your Clarett OctoPre you should have:

• AC mains cable with IEC connector

The User Guide (in English, French, German and Spanish) can be downloaded from

https://global.focusrite.com/downloads

Hardware Features

Front Panel

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The front panel includes all operational controls, metering for all channels and two input sockets for mic, line or instruments.

1. INPUTS 1 & 2 – 2 x “Combo XLR” input sockets for Channels 1 and 2 - connect microphones or line level signals via XLR or ¼” jacks: either TRS (balanced) or TS (unbalanced) jack plugs can be used for instruments or line level signals. Note that the inputs for Channels 3 to 8 are on the rear panel [15].

2. INST 1 & INST 2 – two latching switches put Inputs 1 and 2 into “Instrument” mode. When INST is selected, the gain range and input impedance are altered (relative to LINE), and the input is made unbalanced. This optimises it for the direct connection of instruments via a 2-pole (TS) jack plug. When INST is off, the inputs are suitable for the connection of line level signals. Line level signals may be connected either in balanced form via a 3-pole (TRS) jack or unbalanced, via a 2-pole (TS) jack. Each switch has an internal red LED to conﬁrm selection.

3. 48V (1-4 & 5-8) – two latching switches, each enabling 48 V phantom power at the XLR contacts of four inputs: Channels 1 to 4 and 5 to 8 respectively. Each switch has an associated red LED indicating that phantom power is selected.

4. Input gain controls 1 to 8 – eight rotary controls: adjust the input gain for the signals in Channels 1 to 8 respectively.

5. O/L – each input channel has a red “overload” LED; this illuminates when the signal level reaches +19.5 dBu. Always adjust signal level so that the LED does not illuminate: this will avoid clipping.

6. INSERT/AIR –one “soft” switch per channel, which enables either the rear panel insert point for the channel, or the channel’s AIR function, depending on the setting of the INSERT and AIR master switches [8]. Each switch has an associated bicolour LED, which illuminates green when INSERT is selected or yellow when AIR is selected.

7. Input signal level meters: eight LED bargraphs, one per channel. Segments indicate

-42, -18 & -12 dBFS (green), -6 & -3 dBFS (yellow) and 0 dBFS (red). Input signals are metered post the input gain controls, so you can see the levels being sent to the digital outputs.

8. INSERT and AIR function master switches: two soft switches with internal LEDs (INSERT = green, AIR = yellow) which determine the function of the per-channel INSERT/AIR switches [6].

9. SAMPLE RATE – a soft switch which steps through the six available sample rate settings, the current rate being indicated by one of the adjacent green LEDs. The sample rate in use is stored in memory so that it is retained when the unit is switched off.

10. SYNC – a soft switch which steps through three available digital sync sources (Internal, ADAT or Word clock), the current source being indicated by one of the adjacent red LEDs. The source in use is stored in memory so that it is retained when the unit is switched off.

11. – a green “Locked” LED which illuminates when the unit has locked to the available sync source, indicating that it is ready to use.

12. ADAT > LINE – this soft switch modiﬁes the operating mode of the unit. When not selected, Channels 1 to 8 feed both the rear panel LINE OUTPUT connector (analogue) and the ADAT ports (digital). When ADAT > LINE mode is selected, the LINE OUTPUT connector provides an 8-channel analogue version of the incoming digital audio at the ADAT input ports instead. The adjacent red LED conﬁrms that this mode is active. In this mode, the analogue inputs (Channels 1 to 8) remain routed to the ADAT digital outputs. The mode in use is stored in memory so that it is retained when the unit is switched off.

13. POWER – AC power switch and green LED.

14. Rack ears for mounting the Clarett OctoPre in a standard 19” equipment rack.

Rear Panel

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The remainder of the Clarett OctoPre’s inputs and outputs are on the rear panel.

15. INPUTS 3 to 8 – 6 x “Combo XLR” connectors; note that the inputs for Channels 3 to 8 do not have INST mode, but are otherwise identical to those for Channels 1 and 2.

16. INSERTS 1 & 2 – two ¼” TRS jack sockets, providing an access point for connecting external processing equipment into Channels 1 and 2. The inserts are enabled by the front panel

INSERT/AIR switches [6] and [8], and are unbalanced. The sockets are wired as follows:

Jack contacts Function

Tip Return (input) Ring Send (output) Sleeve Ground

Note that the front panel O/L LED [5] monitors signal level pre the insert send so that excessive signal level is not sent to external equipment.

17. INSERTS 3 to 8 – 6 x ¼” TRS jack sockets providing the insert points for Channels 3 to 8; these are electrically identical to [16].

18. OPTICAL OUT – two TOSLINK connectors providing the digital outputs of the unit. Utilisation of the two connectors is sample rate-dependent, as follows:

Sample Rate OUTPUT 1 (RH port) OUTPUT 2 (LH port)

44.1/48 kHz Channels 1 to 8 Channels 1 to 8

88.2/96 kHz Channels 1 to 4 Channels 5 to 8

176.4/192 kHz Channels 1 & 2 Channels 3 & 4

19. OPTICAL IN – two TOSLINK connectors providing the digital inputs to the unit when used in the ADAT > LINE mode. Note that these are NOT “digital” inputs to Channels 1 to 8, and signals applied at these ports do not pass through the AIR circuitry, nor are available at the inserts. Utilisation of the two connectors is sample rate dependent, as [18].

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