Focusrite ff ISA430 User Manual

Focusrite

audio engineering

ISA430

user’s manual

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Contents

Important Safety Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Power Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1

Signal Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Getting to Know the ISA430 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Metering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Input Stage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

EQ Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Gate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

De-Esser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Limiter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Stereo A/D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Single/Split Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Output Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51

Focusrite Distributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52

Important Safety Instructions

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.

● 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 are
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 capable of operating over a range of mains voltages as
marked on the rear panel. Ensure correct mains voltage setting
and correct fuse before connecting mains supply. Do not change
mains voltage settings while mains supply is connected.

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.

Power Connections

There is an IEC mains lead supplied with the unit which should have
the correct moulded plug for your country. The wiring colour code
used is:

For units shipped to the USA, Canada, Taiwan and Japan:

Live - Black Neutral - White Earth - Green

For units shipped to any other country:

Live - Brown Neutral - Blue Earth - Green and Yellow

Introduction

T

hank you for purchasing the ISA430 brought to you by the
Focusrite team – Trevor, Peter, Martin, Helen, Tom,
Mick, Phil, Chris, Micky, Pauline, Jo, Chris, Nathan, Rob,

Peter and Simon.
The chaps at Focusrite are a jolly hard working bunch and take a

great deal of pride in designing, building and delivering products
which are considered the best audio units around; we hope your
new Focusrite unit lives up to that reputation and that you enjoy
many years of productive recording.

If you would like to tell us about your recording experiences then
email us at: [e-mail]

The Focusrite Team

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Signal Connections

Optional A/D Card shown

INT A/D Direct

The ‘Internal A/D Direct’ input is used to route an external signal
directly to the A/D card via the Limiter. It replaces the ‘Internal’
signal feed to the A/D card (i.e. whatever is connected to the mic,
line or instrument input.)

EXT IP A/D Direct

The External A/D Direct input is used to route an external signal
to the optional A/D card via the Limiter. The signal is normally fed
to the “spare” side of the A/D card not being used by the internal
signal, and so does not replace it. However it is possible to also
sum the External A/D Direct input together with the main internal
signal, (i.e. whatever is connected to the mic, line or instrument
input,) using the ‘sum’ button on the front panel. This will result in
whatever is connected to the External A/D Direct input being
routed to both sides of the A/D converter. For example, a reverb
signal could be processed externally and then be summed with a
dry snare drum signal in this way.

OP1

This output is used as the main analogue internal signal output, and
is fed by whatever is connected to the mic IP, Line IP or Inst. Hi Z
IP, aftyer this signal has been routed through the EQ and dynamics
modules (in ‘single’mode) or through EQ only (in ‘split’ mode.)

Dynamic Link

You can connect two ISA430 units (using a standard stereo jack to
jack lead between the DYNAMIC LINK sockets) to allow the
dynamics sections to behave as a stereo pair of processors. When
connected in this way the dynamics processors behave as if both
units were receiving the same level of signal, with both units
responding to the higher level of the two signal paths. The EQ
channels can be matched visually or aurally to be used as a stereo
pair if required.

Retrofitting the Optional A/D Card

The optional A/D card can be retrofitted to a standard ISA430 at
any time. Full fitting instructions for this option are included with
the Card.

XLR (Audio) Inputs and Outputs

All 3-pin XLR audio connectors (Outputs, Mic/Line Inputs, Insert Send
& Return) are wired as follows:

Pin 1 Screen/Chassis
Pin 2 Audio 0°
Pin 3 Audio 180°

Instrument Input, Key IPS, Int A/D Direct and Dynamic Link

1/4” Jack wired as follows:

Tip Audio 0°
Ring Audio 180°
Sleeve Screen/Chassis

Mic IP/Line IP/Inst. Hi Z IP

Any one of these inputs may be used as the main input to the ISA430.
Signals routed to these inputs are referred to as the ‘internal’ or ‘Int’
signal path.

Insert Return

This is used as the insert input point, or as the input to the dynamics
modules in ‘split mode’ (see ‘Dynamics Split’ diagram on page 7.)

Insert Send

This is used as the insert output point, or as the analogue output from
the dynamics module in ‘split mode’ (see ‘Dynamics Split’ diagram on
page 7.)

Post Mic OP

This is used as an output from the point immediately after the mic pre
(i.e. before EQ and dynamics modules.) It is used as a direct-to-tape
ultra-short signal path output. Taking a signal from this ‘post mic OP’
does NOT interrupt the signal flow from the mic pre to the EQ,
dynamics etc., so a direct feed to tape can be achieved, whilst
simultaneously allowing processing of the same source.

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Getting to Know the ISA430
Power

Applies power to the unit. Turn on the ISA430 before powering up
devices to which the outputs are connected.

Bypass

The EQ and Dynamics processing modules can be globally switched
out using the BYPASS switch, providing a direct route (except for
the protection of the multi-band limiter which remains in the
circuit) from Line Input or External Input to the A/D inputs. This
enables the unit to be used as a 24 bit, 96k stereo converter for
final mastering or for analogue transfer to digital.

Listen LED

This illuminates when LISTEN is selected on the Compressor,
Expander/Gate or De-Esser and indicates that the unit is
monitoring the selected side chain frequencies. Note that the VU
meter continues to show the signal chosen by VU SELECT and not
the LISTEN signal. What you are watching and what you are
hearing can be two different things!

O/L LED

This LED illuminates when the peak signal level reaches or exceeds
+20dB, or when the peak signal level reaches 6dB below clipping.
The signal is monitored at four points: after the input gain TRIM,
after the EQ module, after the Dynamics module and after the
Insert Return, since each module could cause clipping if incorrectly
set up.

Occasional short-duration peaks which may cause the LED to blink
will not normally cause audible distortion, but if the LED is lit
constantly, the level in the appropriate module should be reduced
to prevent overloading.

Inst I/P

Instrument sources may either be connected via the rear panel, or
via this front panel jack.

Metering
VU Select

The VU Meter can display input level, insert return level, or the
compressor gain reduction. Press VU SELECT to step through the
three sources as indicated by the corresponding LEDs. For the
Input and Insert Return, 0VU corresponds to +4dBu. For the
Compressor the meter indicates the amount of gain reduction
caused by compression, from 0VU (no compression) to -20VU
(corresponding to 20dB of gain reduction).

Digital Output Meters

Two LED bargraph meters monitor the Internal signal and the
External signal (whatever is connected to the “Ext I/P A/D Direct”
XLR input) at a point after the Limiter but before the A/D input.
The meters provide a wide range with the O/L LED (lower right
side) acting as an Overload indicator to warn of excessively high
levels at the input of the A/D converters.

Input Stage

Three input options are provided to give compatibility with Mic,
Line or Instrument sources.

An immediately-post-mic pre balanced output (“Post Mic OP”)is
provided on the rear panel giving an ultra-short signal path to allow
for the cleanest possible recordings.

Select

Pressing SELECT steps through each of the three inputs as
indicated by the corresponding LEDs. When the Mic LED is lit, the
Mic input is active etc. Only one of the ‘Mic’, ‘Line’ or ‘Inst’ inputs
can be used simultaneously.

Mic

Mic input sensitivity is switched from -60dB to +6dB in 6dB steps.
Phantom power is available on the rear panel XLR for condenser
mics when +48V front panel switch is pressed.

Line

A Line input is available on XLR, with a switched gain control giving
a range of +/-18dB in 6dB steps.

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Inst I/P

An Instrument input is available on 1/4” jacks on either rear panel
or front panel. This is suitable for high impedance sources such as
guitars or bass pickups (which may be connected directly without
the need for a DI box), or synthesisers with low level outputs.

Trim

The TRIM control provides additional variable gain of 0 to +20dB
for MIC and LINE inputs (white legend), or 0 to +40dB for the
Instrument input (yellow legend).

+48V

Provides +48V powering for condenser mics when pressed.

Phase

Pressing PHASE reverses the phase of the selected input, to
correct phase problems with close microphones or incorrect
wiring polarity.

EQ Module
All EQ

Pressing ALL EQ activates all sections of the EQ module (including
the Hi and Lo Pass Filters), placing the whole module in the audio
path. Toggling ALL EQ allows A/B comparison of EQ settings
without having to use BYPASS which switches both EQ and
Dynamics modules in or out of the audio path. The COMP and
GATE switches on individual EQ sections (see below) operate
independently from the ALL EQ switch.

Filter In

Press in to make the Hi and Lo Pass Filters active in the audio path.
This selection is cancelled if COMP or GATE is pressed.

Both filters provide
18dB/octave rolloff, and
since the filter
frequencies overlap they
may be configured as a
very tight bandpass filter
for creative compression
and gating; use when you
wish to select a specific
instrument or narrow
frequency band from a complex signal, then feed to the sidechain of
the compressor or gate.

Low Pass Filter

A variable control sets a rolloff frequency from 400Hz to 22kHz.

High Pass Filter

A variable control sets a rolloff frequency from 20Hz to 1k6Hz.

Comp

When the COMP switch is pressed both filters are inserted in the
Compressor sidechain for frequency-selective compression. This
selection is cancelled if FILTER IN or GATE is pressed.

Gate

When the GATE switch is pressed both filters are inserted in the
Gate sidechain to assist accurate drum gating. This selection is
cancelled if FILTER IN or COMP is pressed.

PARAMETRIC EQ

Two separate bands of parametric EQ are provided, each with
continuously variable boost/cut with centre detent, sweep control
with two ranges, and variable Q. The first band covers the range
40Hz to 400Hz (120Hz to 1k2Hz when x3 is pressed) and the
second band covers 600Hz to 6kHz (1.8kHz to 18kHz when x3 is
pressed).

Param EQ In

Press in to switch the
Parametric EQ into the
signal path. This selection is
cancelled if GATE or
COMP is pressed.

x3

The Sweep controls have
two ranges, the higher being selected when the x3 switch is
pressed (frequencies shown in yellow on the panel).

Comp

When the COMP switch is pressed, the Parametric EQ is inserted
in the Compressor sidechain allowing frequency-selective
compression. This selection is cancelled if PARAM EQ IN or GATE
is pressed.