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About this User Guide

This user guide applies to the ISA Two mic pre. It provides information about installing and using the 
unit, and how it can be connected into your system.

If you feel that additional information might be of assistance, be sure to consult the site:   

pro.focusrite.com/technical-support

, which contains a comprehensive collection of common 

technical support queries. 

Pro Tools®  and  Pro Tools | HD

TM 

 are trademarks or registered trademarks of Avid Technology, Inc. or its subsidiaries 

in the United States and/or other countries. 

Dante® and Audinate® are registered trademark of Audinate Pty Ltd. 

Box Contents

•   ISA Two unit
•   AC power lead 
•   Safety information cut sheet

INTRODUCTION

Thank you for purchasing the Focusrite ISA Two.

The ISA Two provides two of Focusrite’s prestigious transformer-based microphone preamps, and 
can be used to record microphone, line-level or instrument sources. Microphones and line-level 
sources are connected via the rear panel, whilst instrument inputs can be plugged directly into the 
front panel jack sockets. 

The front panel also features gain, adjustable filter frequency and other settings such as phantom 
power, phase and input impedance for both inputs. Peak level LED metering in dBFS is provided for 
each channel to indicate when the output is reaching the digital clipping point; a meter calibration 
control is provided on the rear panel.

First introduced in 1985, the ISA microphone preamp holds a reputation for outstanding transparency 
along with subtle warmth contributed by transformer core saturation. The variable impedance circuit 
allows ISA users to match the preamp with a wide trange of microphones.

Summary of Contents for ISA TWO

Page 1: ...User Guide focusrite com FA0540 03 Two channel classic transformer mic pre...

Page 2: ...ut Impedance 5 Filter 5 Insert 5 Meter Calibration 6 Rear Panel 7 AC Mains Inlet 7 Channel Mic Inputs 7 Channel Line Inputs 7 Channel Outputs 7 Channel Insert Sends Returns 7 Meter Calibration Pot 7 P...

Page 3: ...e ISA Two The ISA Two provides two of Focusrite s prestigious transformer based microphone preamps and can be used to record microphone line level or instrument sources Microphones and line level sour...

Page 4: ...Gain switch is turned to minimum before pressing the 30 60 switch Before starting a recording or if used for PA live work set theTrim control to near its centre position This will allow for some grad...

Page 5: ...impedance options The values are shown in the table For additional information on impedance selection see Appendix 2 Preamp Input Impedance on page 10 With the Instrument input selected pressing the s...

Page 6: ...lt calibration is for 0 to indicate a signal level of 22 dBu Meter Calibration The level at which the 0 LED illuminates can be adjusted using the Peak Meter Calibration pot on the rear panel The defau...

Page 7: ...4 TRS jack sockets Channel Outputs On XLR 3 male connectors Channel Insert Sends Returns Analogue sends and returns on balanced 1 4 TRS jack connectors The insert signal is added into a channel path...

Page 8: ...ounted in a rack these vents are not obstructed Do not mount the unit immediately above any other equipment which generates significant heat for example a power amplifier Note The maximum operating en...

Page 9: ...creen 2 Hot ve 3 Cold ve Pin Signal 1 Screen 2 Hot ve 3 Cold ve Instrument Input Connector Unbalanced TS 1 4 Jack socket Line Input Insert Send Insert Return Connector Balanced TRS 1 4 Jack socket Pin...

Page 10: ...Impedance In Depth Explanation Dynamic Moving Coil and Condenser Microphones Almost all professional dynamic and condenser microphones are designed to have a relatively low nominal output impedance of...

Page 11: ...es an output transformer to convert the low voltage it generates into a signal capable of being amplified by a preamp The transformer uses a ratio of around 1 30 primary secondary to increase the ribb...

Page 12: ...12 Appendices 3 Pro Tools Interfacing Analogue out to Pro Tools HD ISATwo Red 16Line 2 x XLR 3 female DB25 male analogue Pro Tools interface...

Page 13: ...n Z In Low unless otherwise stated RS 50 Measurements taken at the analogue outputs Gain Range 20 to 10 dB in 10 dB steps plus 0 to 20 dB continuous trim Maximum Input Level 25 dBu Input Impedance Ele...

Page 14: ...imensions Height 88mm 3 46 Width 482mm 18 98 Depth 325mm 12 8 Weight Weight 3 70 kg 8 12 lbs Output Level Maximum output level 24 dBu Environmental Operating Temperature 40 C 104 F Maximum ambient ope...

Page 15: ...of the appropriate procedure for resolving the warranty issue In every case it will be necessary to provide a copy of the original invoice or store receipt to the distributor In the event that you ar...

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