Focusrite ISA One User manual

User Guide
focusrite.com
Version 1.2
FA0187-04
Classic transformer mic pre and optional A-D card with Dante

2
CONTENTS
About this User Guide ..................................................................... 3
INTRODUCTION .............................................................................. 4
ISA ONE CONTROLS AND FEATURES......................................................... 5
Front Panel ................................................................................ 5
Operation.................................................................................. 6
Input Selection.......................................................................... 6
Mic Input Gain .......................................................................... 6
+48V ................................................................................... 6
Z In (Input Impedance – Mic) ............................................................. 6
Line Input Gain ......................................................................... 6
Instrument Input (DI / Amp).............................................................. 6
Z In (Input Impedance – Instrument) ..................................................... 6
Phase .................................................................................. 7
Filter................................................................................... 7
Insert .................................................................................. 7
Phones/Cue Mix ........................................................................ 7
A-D Card Clock and Sync Switches ....................................................... 7
Metering................................................................................... 8
Metering the A-D Inputs ................................................................. 8
Meter Calibration ....................................................................... 8
Rear Panel ................................................................................ 9
A-D Option Card ..........................................................................10
PHYSICAL CHARACTERISTICS ..............................................................11
Power Requirements .....................................................................11
APPENDICES ................................................................................12
1. Connector Pinouts .....................................................................12
2. Preamp Input Impedance ..............................................................14
3. Pro Tools Interfacing ...................................................................16
4. External Clock Input – Unit Differences ................................................17
PERFORMANCE AND SPECIFICATIONS .....................................................18
Focusrite Pro Warranty and Service ......................................................20

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About this User Guide
This user guide applies to the ISA One mic pre. It provides information about installing and using the
unit and how it can be connected into your system.
Also included is information relating to the optional ISA ADN2 A-D interface card, which will allow
audio from the Mic pre to be added to a Dante network.
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 | HDTM 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 One unit
• AC power lead
• Safety information cut sheet

4
INTRODUCTION
Thank you for purchasing the Focusrite ISA One.
The ISA One is a high quality transformer microphone preamplifier which can be used to record
microphone, line-level or instrument sources. Microphone and line-level sources are connected to
the rear panel, whilst an independent instrument input can be plugged directly into the front panel
jack socket. A local amp or combo can also be connected to the front Amp output jack.
The front panel provides independent mic/line and instrument gain controls; settings for phantom
power, phase and impedances for the mic and instrument inputs. The headphone output, with
independent level control, can monitor either the selected channel signal or the stereo Cue input on
the rear panel.
A traditional moving-coil VU and LED peak meters are provided, both with a trim control on the rear
panel for calibration. The second LED peak meter indicates the level at the instrument DI or, when
connected, the external input.
To maintain pristine Focusrite quality in the digital domain, an Analogue-to-Digital interface card
may be fitted into the option slot on the rear panel. This provides access to a Dante network and
features AES3, S/PDIF and ADAT signals.
Once the A-D card is installed, the internal/external clock sample rate and sync source can be
selected using the switches on the front panel.

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ISA ONE CONTROLS AND FEATURES
Front Panel
1 10 dB stepped Mic & Line Gain switch. Mic: 0-30 / 30-60 dB | Line: -20 +10 dB
2 Selects the high mic input range (30-60 dB) on the Gain switch
3 Trim pot: 0 +20 dB for the Mic & Line inputs
4 Applies +48V phantom power to the mic input XLR
5 Inverts polarity (Phase) of the selected input
6 Applies the high-pass filter (HPF) to the selected input
7 Switches the Insert return signal into the channel path
8 Input source selection switch
9 Z In (Input) selects the input impedance for the Mic input
10 Z In (Instrument) selects the input impedance for the Instrument input
11 Gain pot for the Instrument input
12 1/4” mono Jacks for the Instrument input (DI) with a parallel output to an Amp/combo. Also see
rear panel DI output connector on page 9
13 Enables the VU meter calibration mode. See page 8
14 Moving-coil VU and (15) peak-reading LED bargraph Input meters
16 Toggles meters 14 & 15 to indicate the signal at Pre or Post the Insert point
17 Peak-reading LED meter indicates the instrument input (DI) or the EXT IP (when connected)
18 A-D option card clock and sync selection. See page 7
19 1/4” stereo Jack socket for Headphones
20 Headphone volume pot
21 Sends the stereo Cue Mix inputs (on the rear panel) to the headphones
1 3 13 14 16 15 18
2
8
4
9 10 11 12 19 20 21
567
17

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ISA One Controls and Features
Operation
Input Selection
The Input button selects the input source for the main channel path: Mic / Line / Instrument.
A 2nd audio path is available via the DI connector. See ‘Instrument Input’ below, and item 9 on
page 9
Mic Input Gain
The Gain switch adjusts the mic gain in 10 dB steps. Its range is either 0–30 dB or 30–60 dB when
the 30–60 switch is pressed. An additional 0–20 dB of continuous gain adjustment is available using
the Trim control.
To avoid an excessive jump in level, It is recommended that the stepped Gain switch is turned to
minimum before pressing the 30-60 switch.
Before starting a recording, set the Trim control to near its centre position. This will allow for
some gradual gain adjustment up or down without the use of the stepped control.
+48V
Pressing the +48V button applies phantom power to the Mic input XLR. This switch does not affect
the Line or Instrument inputs.
If you are unsure whether your microphone requires phantom power please refer to its handbook.
Certain microphones (most notably ribbon and unbalanced mics) could be damaged by applying
phantom power.
Z In (Input Impedance – Mic)
With the Mic input selected, pressing the Z In button steps through the four
transformer preamp input impedance options. The values are shown in the
table.
For information on impedance selection see Appendix 2, “Preamp Input
Impedance” on page 14.
The Line input impedance is xed at 10 kΩ and is not affected by the Z In switch.
Line Input Gain
The Gain switch adjusts the gain between -20 dB and +10 dB in 10 dB steps. Continuous gain
adjustment of up to 20 dB can be added using the Trim control.
Instrument Input (DI / Amp)
The Instrument input is via a standard 1/4” mono jack (DI) on the front panel. The
level is set using the Gain control and is continuously adjustable from +10 dB to +40 dB.
The adjacent Amp Jack provides a parallel feed for connection to a guitar amplifier/combo.
A permanent line level feed of the instrument signal is provided on the DI O/P connector on the rear
panel.
Z In (Input Impedance – Instrument)
Pressing the switch toggles between High (guitar pickups) and Low (vintage/
high Z-out equipment) settings. The values are shown in the table.
Low 600 Ω
ISA 110 1.4 kΩ
Med 2.4 kΩ
High 6.8 kΩ
Mic Impedance
Low 470 kΩ
High 2.4 MΩ
Instrument Impedance

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Phase
Pressing Phase inverts the polarity of the selected input. This can be useful when multiple mics are
used in close proximity (ie., on a drum kit).
Filter
Pressing the Filter button inserts the 18 dB/octave 75 Hz high-pass filter into channel path; it is
applied to whichever input is selected.
The lter is useful for removing any unwanted low frequencies, eg., rumble transmitted through
oor mounted mic stands, etc.
Insert
Pressing Insert places the Insert Return signal into the channel path before the Output connector,
allowing the inclusion of external effects units.
The Insert Send is always available and is post the input Gain and Filter & Phase controls.
Phones/Cue Mix
Standard stereo headphones can be connected to the front panel 1/4” jack socket. The signal being
sent to the headphones is determined by the status of the Cue Mix switch:
• Cue Mix Switch Off – The headphone feed will be a nonadjustable mono mix of two separate
sources: (1); the selected input (Mic, Line or Inst) and (2); either the DI or the EXT I/P signal.
This, for example, allows a mic (via the rear panel) and a guitar (via the DI jack) / or a keyboard
(via the Ext I/P jack) to be monitored simultaneously.
Note that if ‘Inst’ is selected as the input (with no Ext I/P jack) the instrument will be the only
source heard
• Cue Mix Switch On – The headphones will now monitor the Cue Mix Left and Right inputs on the
rear panel in stereo. Changing input selection and/or inserting an Ext I/P jack will not affect the
headphone source.
A-D Card Clock and Sync Switches
Clock select
Allows the user to select the internal sample frequency: 44.1kHz, 48kHz, 88.2kHz,
96kHz, 176.4kHz, or 192kHz.
Ext
Allows the ISA ADN2 A-D card to follow an external Word Clock source. Press the
switch to toggle between standard and Dante clock.
Lock LED
Indicates that the unit is successfully synchronised to the external Word Clock.
On earlier ISA One units, the lock LED may ash under certain conditions. Please refer to
Appendix 4, on page 17 for additional information.

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Metering
ISA One’s front panel provides three level meters: a traditional
moving-coil VU meter – which shows the average volume
level, plus two peak-reading LED bargraphs – which indicate
dBFS, ie., the level in dB, relative to maximum output (when
the red ‘0’ LED illuminates).
The VU meter and the left Input LED bargraph are linked and both indicate the main signal (the
selected Input, post Gain & Filter) at the point set by the status of the Post Insert switch:
• Post Insert Switch Off – The VU and Input LEDs indicate the signal level at the Insert Send
connector. This will also be the Main O/P when the Insert switch is off.
• Post Insert Switch On – The VU and Input LEDs now indicate the signal level at the Insert Return
connector. This will also be the Main O/P when the Insert switch is on.
The right DI/Ext bargraph indicates the level at one of two different signal locations, determined by
the presence of a jack at the rear Ext I/P socket:
• Ext I/P unused – The right LED meter indicates the level at the DI O/P connector.
• Ext I/P jack inserted – The right LED meter now indicates the level at the external input.
Metering the A-D Inputs
The two inputs to the A-D option card are fed from; Ch.1: the Main O/P; Ch.2: the Ext I/P.
With the Ext I/P jack connected – and the left LED meter indicating the Main O/P (see above) – the
LED bargraphs will display both signals being sent to the A-D card inputs.
At default calibration, LED ‘0’ indicates a signal level of 22 dBu, which is the maximum input
level of the A-D card.
Meter Calibration
The calibration of the VU and LED meters can be adjusted using trim controls on the rear panel. Note
that changes to the VU meter calibration will only take effect by pressing the VU Cal switch.
• VU Meter – The default VU meter lineup (VU Cal switch off) is 0 VU = 4 dBu.
With the VU Cal switch on, rotating the VU Meter Cal knob will set the value at between
0 VU = 11 dBu (fully anti-clockwise) and 0 VU = 26 dBu (fully clockwise), with 0 VU =
22 dBu at the centre detent position.
• LED Meters – The default setting of 0 dBFS = 22 dBu occurs when the knob is in its
central detent position – to correspond with the maximum input level of the A-D card.
Rotating the Peak Meter Cal knob will set the value at between 0 dBFS = 15 dBu (fully
anti-clockwise) and 0 dBFS = 26 dBu (fully clockwise).

9
1 Mains power switch.
2 Standard IEC receptacle for AC mains. ISA One features a ‘Universal’ PSU, enabling it to operate
on any supply voltage between 100 and 240 V AC
3 Slot for ISA ADN2 analogue to digital conversion card. The card allows two audio signals from
the ISA One to be added to a Dante network. It also provides AES3, S/PDIF and ADAT signals.
See the following page for A-D card details
4 Adjusts the VU meter ‘0’ indication between 11 and 26 dBu. At the detent position the reading
will be 22 dBu – which matches the maximum input level of the A-D card
The Cal control only takes effect when the front panel “VU Cal” button is pressed. When not
pressed, VU ‘0’ indicates a level of 4 dBu
5 Adjusts the LED meters reading at full scale between 15 and 26 dBu. At the detented position
the reading will be 22 dBu
6 Balanced 1/4” TRS Jack sockets for the Left and Right Cue Mix inputs
7 Balanced 1/4” TRS Jack socket (Ext I/P) which feeds input 2 of the A-D option card
8 Balanced 1/4” TRS Jack sockets for Insert Send and Return. The insert can be added into the
channel path by pressing the front panel Insert switch
9 XLR-3 male provides a Line-level output of the instrument signal (DI). The signal is post the
instrument gain control and is always available irrespective of any switch selection
10 XLR-3 male for the Main channel output – as selected by the front panel Input button. This
output is linked internally to input 1 of the A-D option card
11 Balanced 1/4” TRS jack and (12) XLR-3 female connector for the Line input. The connectors are
internally linked so must not be connected to different sources
13 Balanced XLR-3 female connector for microphone input. Phantom power can be applied by
pressing the +48V switch
Rear Panel
1
2 5 9
3
10 1211 13
4
6
7
8

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A-D Option Card
The optional ISA ADN2 A-D card can be retrofitted to an ISA One at any time. Engineering experience
is not required as the card can easily be installed by the user.
Note that the ISA One does not support the earlier ISA 2-Channel A-D card.
Once fitted, configuration of the card is carried out over the network using either RedNet Control or
the Dante Controller software application.
The tting instructions and network software applications are included with the A-D card option.
Word Clock – Input
Allows the card to be synchronised to an external Word Clock source via the BNC connector.
Word Clock – Output
Provides an output of the external Word Clock source connected at the “Word Clock In” BNC connector
or, transmits the internal sample frequency of the A-D card.
• When the ISA One is following other units within a larger digital system, the Word Clock Out
connector can be used to pass on the Word Clock signal to the next device.
• When the unit is not following another device and is in Internal Clock mode, the Word Clock
Out connector outputs the sample frequency selected on the ISA One front panel.
Primary Network Port
Latching RJ45 connector for the Dante network. Use standard Cat 5e or Cat 6 network cable to
connect the ISA ADN2 to a local Ethernet switch which is connected to the Dante network. Adjacent
to the network sockets are LEDs which illuminate to indicate a valid network connection and network
activity.
Secondary Network Port
Can be used as the Secondary Dante network connection where two independent Ethernet links are
being used (Redundant mode), or as an additional port on an integral network switch on the primary
network (Switched mode).
ADAT
2-channel ADAT optical output using standard TOSLINK connector.
S/PDIF I/O
2-channel digital interface on RCA (phono) connector.
AES3 Output
2-channel AES3 output on XLR-3 male connector.
See Appendix 1 for connector pinouts. See Appendix 3 for Pro Tools interfacing information.

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ISA One dimensions are illustrated in the diagram above. Allow for an additional 75mm [3”] behind
the unit to allow for cable connections.
ISA One comes in a freestanding case fitted with a top-mounted carrying handle. It weighs 3.9 kg
[8.6 lbs] and is equipped with rubber feet for table mounting.
ISA One generates little significant heat and is cooled by natural convection. Vents are provided at
each side; ensure that when mounted close to other equipment these vents are not obstructed. Do
not position the unit immediately above any other equipment which generates significant heat, for
example, a power amplifier.
Note. The maximum operating environmental temperature is 40°C / 104°F.
Power Requirements
ISA One is mains powered and incorporates a ‘Universal’ power supply which can operate on any AC
mains voltage from 100 V to 240 V. The AC connection is via a standard 3-pin IEC connector on the
rear panel.
A mating IEC cable is supplied with each unit – this should be terminated with a mains plug of the
correct type for your country.
Power consumption for ISA One is 35 W.
Please note that there are no fuses or other user-replaceable components of any type in any unit.
Please refer all servicing issues to the Customer Support Team (see “Customer Support and Unit
Servicing” on page 20).
PHYSICAL CHARACTERISTICS
220mm / 8.7”
290mm / 11.4”
104mm / 4.1”

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APPENDICES
1. Connector Pinouts
Mic Input / Line Input
Connector: XLR-3 female
Main Output / DI Output
Connector: XLR-3 male
Pin Signal
1 Screen
2 Hot (+ve)
3 Cold (–ve)
Pin Signal
1 Screen
2 Hot (+ve)
3 Cold (–ve)
Instrument Input / DI Output
Connector: Unbalanced (TS) 1/4” Jack socket
Line Input / Insert Send & Return
Ext Input / Cue Mic In Left & Right
Connector: Balanced (TRS) 1/4” Jack socket
Pin Signal
Tip Hot (+ve)
Ring Cold (–ve)
Sleeve Ground
Pin Signal
Tip Hot (+ve)
Sleeve Ground
Tip Ring Sleeve
Tip Sleeve

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1. Connector Pinouts...
Network 1 & 2
Connector type: RJ-45 receptacle
Pin Cat 5/6 Core
1 White + Orange
2 Orange
3 White + Green
4 Blue
5 White + Blue
6 Green
7 White + Brown
8 Brown
1
8
ADAT Optical Interface
Connector: TOSLINK
S/PDIF
Connector: RCA (Phono)
Word Clock In & Out
Connector: BNC 75Ω
ISA ADN2 Option Card:
AES3 Out
Connector: XLR-3 female
Pin Signal
1 Screen
2 Out Ch. 1&2 +
3 Out Ch. 1&2 -

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Appendices...
2. Preamp Input Impedance
A major element of the sound of a mic pre is related to the interaction between the specific microphone
being used and the type of mic preamp interface technology it is connected to. The main area in which
this interaction has an effect is the level and frequency response of the microphone, as follows:
Level
Professional microphones tend to have low output impedances and so more level can be achieved by
selecting the higher impedance positions of the ISA One mic preamp.
Frequency response
Microphones with defined presence peaks and tailored frequency responses can be further enhanced
by choosing lower impedance settings. Choosing higher input impedance values will tend to
emphasise the high frequency response of the microphone connected, allowing you to get improved
ambient information and high end clarity – even from average-performance microphones. Various
microphone/ISA One preamp impedance combinations can be tried to achieve the desired amount
of colouration for the instrument or voice being recorded. To understand how to use the impedance
selection creatively, it may be useful to read the following section on how the microphone output
impedance and the mic preamp input impedance interact.
Switchable 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 between 150 Ω and 300 Ω when measured at 1 kHz. Microphones are
designed to have such low output impedance because the following advantages result:
• They are less susceptible to noise pickup
• They can drive long cables without high frequency roll-off due to cable capacitance
The side-effect of having such low output impedance is that the mic preamp input impedance
has a major effect on the output level of the microphone. Low preamp impedance loads down the
microphone output voltage, and emphasizes any frequency-related variation in microphone output
impedance. Matching the mic preamp resistance to the microphone output impedance (eg., making
a preamp input impedance 200 Ω to match a 200 Ω microphone) still reduces the microphone output
and signal to noise ratio by 6 dB, which is undesirable.
Impedance Setting – Quick Guide
In general the following selections will yield the following results:
High mic preamp impedance settings:
• Will generate more overall level
• Will tend to make low- and mid-frequency response of the microphone flatter
• Will improve high-frequency response of the microphone.
Low preamp impedance settings:
• Will reduce the microphone output level
• Will tend to emphasise the low- and mid-frequency presence peaks and
resonant points of the microphone

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2. Pre Amp Impedance...
To minimise microphone loading, and to maximise signal to noise ratio, preamps have traditionally
been designed to have an input impedance about ten times greater than the average microphone,
around 1.2 kΩ to 2 kΩ. (The original ISA 110 preamp design followed this convention and has an
input impedance of 1.4 kΩ at 1 kHz.) Input impedance settings greater than 2 kΩ tend to make the
frequency-related variations of microphone outputs less significant than at low impedance settings.
Therefore high input impedance settings yield a microphone performance that is flatter in the low
and mid frequency areas and boosted in the high frequency area when compared to low impedance
settings.
Ribbon Microphones
The impedance of a ribbon microphone is worthy of special mention, as this type of microphone is
affected enormously by preamp impedance.
The ribbon impedance within this type of microphone is very low, around 0.2 Ω, and requires 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 ribbon
voltage to a useful level. This transformer ratio has the effect of increasing the output impedance of
the mic to around 200 Ω at 1 kHz.
The transformer impedance, however, is very dependent upon frequency – it can almost double at
some frequencies (known as the resonance point) and tends to roll off to very small values at low
and high frequencies. Therefore, in common with dynamic and condenser microphones, the mic
preamp input impedance has a significant effect on the signal level and frequency response of the
ribbon microphone output transformer, and the associated ‘sound quality’ of the microphone. It is
recommended that a mic preamp connected to a ribbon microphone should have an input impedance
of at least 5 times the nominal microphone impedance.
For a ribbon microphone impedance of 30 Ω to 120 Ω, the input impedance of 600 Ω (Low) will work
fine. For 120 Ω to 200 Ω ribbon microphones, the input impedance setting of 1.4 kΩ (ISA 110) is
recommended.

16
Appendices...
3. Pro Tools Interfacing
• Analogue out to Pro Tools | HD
• Dante to Pro Tools | HD
ISA One
ISA One
Red 16Line
RedNet HD32R
2 x XLR-3 female – DB25 male analogue
RJ45 – RJ45 network
RJ45 – RJ45 network
Pro Tools interface
In Ch. 1
Mic/Line/Inst
In Ch. 2
Ext I/P
Pro Tools interface
Dante Network

17
Appendices...
4. External Clock Input – Unit Differences
The way in which ISA One responds to an external clock selection will vary slightly depending on the
unit’s revision.
On earlier units, the EXT clock input selections will include a 256X setting rather than the Dante
Clock setting used on later units.
Front Panels Marked “256X”
The front panel EXT LED indicators will only follow the rate selected if the change is made using the
front panel switch.
If a change to the external clock is made over the network, the front panel LED won’t update, and the
LOCK LED will start flashing.
Note that the unit will still operate correctly – it will still follow the RNC2 or the front panel
switch selection – but it won’t have updated the front panel LED indication.
When a change is made from the front panel, the unit will always toggle to whichever would be the
next selection. For example: if the front panel is set to 48k, and the setting is changed to 44.1k via
RNC2, 88.2k will still be the next sample rate selected by pressing the button on the front panel. This
behaviour is the same for the sync source.
Front Panels Marked “Dante Clock”
On newer units the EXT LEDs will always indicate the correct setting whether changes are made
from the front panel or via the network.

18
PERFORMANCE AND SPECIFICATIONS
Microphone Inputs
All measurements taken at minimum gain, Z In: medium, unless otherwise stated. Measurements taken at the
analogue outputs
Gain Range 0 to 30 dB or 30 to 60 dB (with ‘30-60’ switch enabled), in 10 dB steps,
plus 0 to 20 dB of continuous trim
Maximum Input Level +7 dBu
Input Impedance Transformer balanced, Low: 600 Ω, ISA 110: 1.4 kΩ, Medium: 2.4 kΩ, High: 6.8 kΩ
Signal-to-Noise Ratio 122 dB ‘A’-Weighted (typical), maximum gain
Frequency Response 20 Hz – 20 kHz ± 0.2 dB | 10 Hz – 110 kHz ± 1.5 dB
THD + N -92 dB (0.0025%) @ -1 dBr
High-Pass Filter 75 Hz knee frequency, 18 dB/octave
EIN <-123 dBu ‘A’-Weighted (typical), maximum gain
Common Mode Rejection
Ratio
-93 dB @ 1kHz
Line Inputs
All measurements taken at minimum gain, Z In: Low, unless otherwise stated, RS = 50 Ω. 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 Electronically balanced 10 kΩ
Signal-to-Noise Ratio 122 dB ‘A’-Weighted (typical), maximum gain
Frequency Response 20 Hz – 20 kHz ± 0.1 dB | 10 Hz – 122 kHz ± 3 dB unity gain
THD + N -91 dB (0.0028%) @ -1 dBr
High-Pass Filter 75 Hz knee frequency, 18 dB/octave
Common Mode Rejection
Ratio
-65 dB @ 1 kHz
Instrument Inputs
All measurements taken at minimum gain, Z In: Low, unless otherwise stated, RS = 600 Ω. Measurements taken at the
analogue outputs
Gain Range +10 to +40 dB continuous, using Trim pot
Maximum Input Level +18 dBu
Input Impedance Low: 470 kHz, High: 2.4 MΩ
Signal-to-Noise Ratio 100 dB ‘A’-Weighted
Frequency Response 20 Hz – 20 kHz ±0.1 dB | 10 Hz – 110 kHz ± 1.2 dB
THD + N -83 dB (0.0071%) @ -1 dBFS
High-Pass Filter 75 Hz knee frequency, 18 dB/octave

19
Performance and Specications . . .
Crosstalk
All measurements taken at minimum gain, Z In: Medium
Microphone Inputs -60 dB, 20 Hz – 20 kHz
Line Inputs -80 dB, 20 Hz – 20 kHz
Instrument Inputs -80 dB, 20 Hz – 20 kHz
Power
PSU 1 x Internal, 100 – 240 V, 50 / 60 Hz
Consumption 35 W.
Dimensions
Height 104mm / 4.1”
Width 220mm / 8.7”
Depth 290mm / 11.4”
Weight
Weight 3.9 kg / 8.6 lbs
Environmental
Operating Temperature 40°C / 104°F Maximum ambient operating temperature
Connectivity
Front panel
Instrument input /
Amp output
2 x 1/4” mono jack
Rear Panel
Microphone input XLR-3 female
Line level input
Main output
DI output
1/4” balanced jack & XLR-3 female
XLR-3 male
XLR-3 male
Insert send
Insert return
1/4” balanced jack
1/4” balanced jack
Cue Mix inputs L & R 2 x 1/4” balanced jack
Digital Card Slot
Compatible card ISA ADN2

20
Focusrite Pro Warranty and Service
All Focusrite products are built to the highest standards and should provide reliable performance for
many years, subject to reasonable care, use, transportation and storage.
Very many of the products returned under warranty are found not to exhibit any fault at all. To
avoid unnecessary inconvenience to you in terms of returning the product please contact Focusrite
support.
In the event of a Manufacturing Defect becoming evident in a product within 36 months from the date
of the original purchase Focusrite will ensure that the product is repaired or replaced free of charge.
A Manufacturing Defect is defined as a defect in the performance of the product as described and
published by Focusrite. A Manufacturing Defect does not include damage caused by post-purchase
transportation, storage or careless handling, nor damage caused by misuse.
Whilst this warranty is provided by Focusrite the warranty obligations are fulfilled by the distributor
responsible for the country in which you purchased the product.
In the event that you need to contact the distributor regarding a warranty issue, or an out-of-warranty
chargeable repair, please visit: pro.focusrite.com/rest-of-the-world
The distributor will then advise you 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 are unable to provide proof of purchase directly then you should
contact the reseller from whom you purchased the product and attempt to obtain proof of purchase
from them.
Please do note that if you purchase a Focusrite product outside your country of residence or business
you will not be entitled to ask your local Focusrite distributor to honour this limited warranty,
although you may request an out-of-warranty chargeable repair.
This limited warranty is offered solely to products purchased from an Authorised Focusrite Reseller
(defined as a reseller which has purchased the product directly from Focusrite Audio Engineering
Limited in the UK, or one of its Authorised Distributors outside the UK). This Warranty is in addition
to your statutory rights in the country of purchase.
Registering Your Product
To access optional bundled software, please register your product at: focusrite.com/register
Customer Support and Unit Servicing
You can contact our Customer Support team free of charge:
Email: [e-mail]
Phone (UK): [phone]
Phone (USA): [phone]
Troubleshooting
If you are experiencing problems with your ISA One, we recommend that in the first instance, you visit
our Support Help Centre at: pro.focusrite.com/help-centre