Alesis AI-1 User manual

ALESIS
AI-1
Reference Manual

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TABLE OF CONTENTS
CHAPTER 1 : INTRODUCTION
1.0 ABOUT THE AI-1 ......................................................................1
1.1 IMPORTANT NOTES ABOUT THIS MANUAL..................3
1.2 OVERVIEW OF MAIN FUNCTIONS.....................................3
1.2A Digital Interface............................................................3
1.2B Digital Audio Synchronization....................................4
1.2C Sample Rate Conversion ..............................................4
1.3 BASIC OPERATION.................................................................5
1.3A Source ............................................................................5
1.3B Destination.....................................................................6
1.3C ADAT Channel .............................................................6
1.3D Destination Rate............................................................7
CHAPTER 2 : HOOKUP
2.0 POWER........................................................................................8
2.1 CONNECTION TO ADAT(S)..................................................8
2.1A Single ADAT.................................................................8
2.1B Multiple ADATs without the BRC...............................9
2.1C Connecting the BRC.......................................................11
2.2 AES/EBU AND S/PDIF..............................................................13
2.2A Connecting an AES/EBU Device................................13
2.2B Connecting an S/PDIF Device.....................................14
2.3 48 kHz CLOCK OUT .................................................................15
2.4 POWERING-UP .........................................................................15
CHAPTER 3 : TRANSFERRING DIGITAL AUDIO
3.0 AI-1 TO ADAT...........................................................................16
3.0A Source ............................................................................16
3.0B Selecting Record Tracks................................................17
3.0C Destination ....................................................................18
3.0D Converting Sample Rate ..............................................18
3.1 ADAT TO AI-1...........................................................................18
3.1A Source ............................................................................19
3.1B Selecting Source Tracks ................................................19
3.1C Destination ....................................................................19
3.1D Converting Sample Rate ..............................................19
3.2 USING THE BRC.......................................................................20
3.2A Digital Input..................................................................20
3.2B Bouncing Tracks Between ADATs...............................21
3.2C Recording from AI-1 onto ADAT................................23

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3.2D BRC Synchronization ...................................................26
3.2E Output ADAT Tracks to AI-1.......................................26
3.2F Bouncing Tracks While Outputting To AI-1...............28
3.3 CONFIGURATIONS.................................................................29
3.3A ADAT to AES/EBU (48kHz).......................................30
3.3B AES/EBU to ADAT (48kHz)........................................30
3.3C AES/EBU to ADAT (44.1kHz to 48kHz)....................31
3.3D ADAT to AES/EBU (48kHz to 44.1kHz)....................31
3.3E AES/EBU to ADAT (44.1kHz).....................................32
3.3F ADAT to S/PDIF (48kHz) ............................................33
3.3G S/PDIF to ADAT (48kHz)............................................33
3.3H S/PDIF to ADAT (44.1kHz to 48kHz)........................34
3.3I ADAT to S/PDIF (48kHz to 44.1kHz)..........................34
3.3J S/PDIF to ADAT (44.1kHz)..........................................35
3.3K ADAT to ADAT............................................................36
3.3L AES/EBU to AES/EBU ................................................37
3.3M S/PDIF to S/PDIF........................................................37
CHAPTER 4 : APPENDICES
4.0 APPENDIX 1
SPECIFICATIONS..................................................................39
4.1 APPENDIX 2
MAINTENANCE/SERVICE INFORMATION...................41
4.1A Cleaning ........................................................................41
4.1B Maintenance...................................................................41
4.1C Servicing........................................................................41

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CHAPTER 1: INTRODUCTION
1.0 ABOUT THE AI-1
Congratulations! You’ve just purchased a powerful tool that will
enhance your ADAT system with incredible digital audio routing
flexibility. The AI-1 Digital Interface and Sample Rate Converter
provides you a way of routing any two ADAT tracks to another
digital recording system, or the other way around, and will convert
the sampling rate as needed. The AI-1 is essential for either
recording digital audio from other sources onto ADAT, or mixing
down a 2 track mix from ADAT to a DAT machine or CD recorder,
all while remaining in the digital domain. Here are some of the
features the AI-1 will provide you:
•High quality, dual-channel digital interface. The AI-1 provides
the connection between AES/EBU, S/PDIF and ADAT digital
formats. With it, you can interface your ADAT digital audio with
various professional and consumer digital audio products (such
as DAT and CD recorders, and digital audio workstations) with
the assurance that the audio never leaves the digital domain.
•Sample rate conversion. The AI-1 can automatically detect the
sampling rate of an incoming digital audio source. When you
want to convert that source, it will transform a 44.1kHz clock to
48kHz, or vice-versa. When routing ADAT digital audio to
another digital destination, the AI-1 can convert the ADAT’s
48kHz sample rate to 44.1kHz (this is especially useful for
creating a mix that’s ready for transfer to CD).
•Sample accurate syncing capabilities. Using ADAT’s exclusive
Proprietary Synchronization Interface, the AI-1 keeps perfect time
with the system. Each ADAT tape is “formatted” with a
proprietary Alesis time code that is much more accurate than
SMPTE or other time code systems. This process time-stamps the
tape to an incredible single-sample accuracy; that is, 1/48,000th of
a second. The AI-1 uses the ADAT’s timecode to keep perfectly
synchronized while transferring digital audio.
•Simple to use. The AI-1’s front panel is extremely easy to
understand and operate. Just select the source, destination,

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track(s) and the sampling rate…and you’re up and running!
With the BRC Master Remote Control, it’s even easier since all
AI-1 controls are available from the BRC’s Digital I/O edit menu.
•Optic digital interface. ADAT’s Proprietary Multichannel Optic
Digital Interface carries up to eight tracks simultaneously via
optic cable, allowing for perfect, degradation-free digital
dubbing between ADATs. With analog recording, bouncing
tracks or backing up from one multitrack to another loses one
generation, which adds hiss and distortion. With digital
recording, such procedures will produce a “clone” of the
original. This makes it easy to create extra copies of tracks or
safety copies of entire tapes, or make multiple copies for
distribution. The AI-1 lets you choose a pair of tracks from a
single ADAT, and output them to the AES/EBU and S/PDIF
connections. This allows for direct digital connection to and from
other digital audio recorders, DAT recorders, CDs, hard disk
recorders, synthesizers, and more.
•Fast and easy hookup. Connection of the AI-1 is accomplished
via fiber optic digital audio cables, which connect the AI-1 to and
from a single ADAT or multiple ADAT system. Connection to
AES/EBU devices is provided via XLR type connectors.
Connection to S/PDIF devices is provided by both fiber optic
and RCA connectors.
When used with the BRC and multiple ADATs, the Sync Out of
the last ADAT in the chain is connected to the Sync In of the AI-
1, using a 9 pin style sync cable. The last ADAT’s digital out is
connected to the AI-1’s digital in, and the AI-1’s digital out is
connected to the digital in of the first ADAT, using fiber optic
cables.
When the BRC is turned on, it automatically becomes the
system’s master, and assigns each ADAT an identification
number, from first to last in the chain. The BRC also
automatically checks to see if an AI-1 is connected, and provides
remote control over all of its functions.
•Voltage tolerant power supply. The AI-1 accepts any AC
voltage between 90 and 250 volts.
For more information on digital recording, see Appendix 1 in the
ADAT manual. Appendix 2 in the ADAT manual is a glossary of

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digital recording terms that may be helpful as you read this manual.
1.1 IMPORTANT NOTES ABOUT THIS
MANUAL
This manual has been designed as a reference to assist the recording
professional in learning the basic operation of the AI-1. All functions
are explained in a clear manner, using step-by-step instructions and
illustrations for setting up and performing various operations.
However, it is assumed that you already have some understanding
of multitrack recording and digital audio in general. It also assumes
you have read the ADAT manual (and the BRC manual, if you are
using the BRC) and comprehend its/their operation.
If you have little or no previous experience with multitrack
recording or working with digital audio, please read the second
manual that comes with the BRC Master Remote Control, entitled
BRC Concepts and Applications. It will give you an understanding
of how an ADAT/BRC/AI-1 system functions in real world
applications, and the types of things you may expect. It explains
why certain features are significant, and how to employ them in
your recording routine. Most importantly, there are simple tutorials
for commonly performed operations, which illustrate exactly how to
put it all together.
In this manual, all connectors, buttons and LEDs are spelled with all
capital letters (such as S/PDIF LED button or SOURCE ADAT
button).
1.2 OVERVIEW OF MAIN FUNCTIONS
Here is a brief rundown of the AI-1’s main functions:
1.2A Digital Interface
The AI-1 provides conversion between ADAT, AES/EBU and
S/PDIF digital formats. This means you can record from other
digital audio devices onto ADAT, or vice-versa, without ever

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leaving the digital domain. The AI-1 can be used to transfer digital
audio back and forth between DAT machines, CD player/ recorders
and digital audio workstations. Whenever you transfer digital audio
through the AI-1, the result is a perfect, exact duplicate of the
original with no degradation or change in audio quality.
1.2B Digital Audio Synchronization
All digital audio protocols, whether Alesis’ Proprietary
Multichannel Optical Digital Interface or AES/EBU format, transmit
data plus a timing clock that dictates the speed at which the data
will be recorded or played back. This timing clock is related to the
sample rate. The ADAT speed is controlled automatically to
conform to this sample rate whenever its DIGITAL IN LED is lit.
Therefore, the PITCH controls on the ADAT have no effect when
performing digital transfers onto ADAT.
1.2C Sample Rate Conversion
The AI-1 also provides conversion between 48kHz and 44.1kHz
sampling rates. If you are recording onto ADAT from a source that
is running at 44.1kHz, you can either record at the same rate, or
convert it to ADAT’s superior 48kHz sampling rate. One of the best
ways to use ADAT is not only as a multitrack recorder, but as a
mixdown recorder as well, using two tracks to mix to. Using the AI-
1, you can transfer the two-track mix to DAT or a CD recorder and
simultaneously convert the audio to the required 44.1kHz sample
rate.
Because of its superior sound quality, it is always better to record
onto ADAT at the 48kHz rate, even when the original audio was
recorded at 44.1kHz. Contrary to what many people think,
converting 44.1kHz audio to 48kHz does not change the sound
quality in any way. If, however, you choose to not to convert such
an audio source and record it onto ADAT at 44.1kHz, don’t be
surprised when you play back the ADAT recording and hear the
music a little faster and transposed up a bit. This is because 48kHz is
literally a faster sampling rate than 44.1kHz. When the AI-1 sends
44.1kHz audio to ADAT, the ADAT’s motor slows down to match
the rate of the incoming audio. If you are monitoring other pre-
recorded tracks on the same machine, you’ll notice that they are
now slower and transposed down.

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When you play back the audio once it is on ADAT, it will adjust
back to its normal speed and of course sound sharp…roughly 147
cents sharp. If you want to hear the audio on ADAT at the original
pitch and speed, bring the ADAT’s pitch setting down to -147.
Doing so will temporarily show “44.1” in the ADAT’s LED display,
indicating that you are now running at the equivalent to the
44.1kHz rate.
1.3 BASIC OPERATION
When power is first turned on, the AI-1 recalls the most recent mode
of operation (the last mode before power down). The mode is
indicated by the LEDs in the control buttons. These buttons are used
to change the operating mode. The ADAT CHANNEL buttons, the
DESTINATION RATE buttons, and the SOURCE and
DESTINATION buttons define the possible uses of the AI-1.
1.3A Source
The three SOURCE buttons (ADAT, AES/EBU, and S/PDIF) are
used to select the digital source. When one of these buttons is
pressed, its LED will be lit indicating it has been selected. Only one
of the sources can be selected at a time; the corresponding format
input will be enabled, while the others will be disabled.
Here are descriptions of the three Source possibilities:
•ADAT: This allows two tracks from a connected ADAT to be
transmitted to another ADAT, or an AES/EBU or S/PDIF device
(depending on the Destination setting).
•AES/EBU: This allows two tracks from a connected AES/EBU
device to be recorded to an ADAT, or another AES/EBU device,
or an S/PDIF device (depending on the Destination setting).
•S/PDIF: This allows two tracks from a connected S/PDIF device
to be recorded to an ADAT, or another S/PDIF device, or an
AES/EBU device (depending on the Destination setting).
If the selected Source button’s LED lights solid, it means that a

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device is connected, and the AI-1 is receiving its clock information.
If the selected Source button’s LED flashes, it means that either no
device is connected to the selected input, or the clock information is
not being provided by the source to the AI-1, or the clock
information being provided by the source is neither 48kHz or
44.1kHz (see section 1.3D)
1.3B Destination
The three DESTINATION buttons (ADAT, AES/EBU, and S/PDIF)
are used to select the digital destination. When one of these buttons
is pressed, its LED will be lit indicating it has been selected. Only
one of the destinations can be selected at a time; the corresponding
format output will be enabled, while the others will be disabled.
Here are descriptions of the three Destination possibilities:
•ADAT: This routes the AI-1 output to a connected ADAT for
recording from another ADAT, or an AES/EBU or S/PDIF
device (depending on the Source setting).
•AES/EBU: This routes the AI-1 output to a connected AES/EBU
device for recording from an ADAT, or another AES/EBU
device, or an S/PDIF device (depending on the Source setting).
•S/PDIF: This routes the AI-1 output to a connected S/PDIF
device for recording from an ADAT, or another S/PDIF device,
or an AES/EBU device (depending on the Source setting).
1.3C ADAT Channel
The four ADAT CHANNEL buttons (1/2, 3/4, 5/6, and 7/8) are
used to select two channels on which an ADAT will transmit or
receive digital audio. When one of these buttons is pressed, its LED
will be lit indicating it has been selected. Only the four defined
channel groupings (1 & 2, 3 & 4, 5 & 6, or 7 & 8) may be selected
from the front panel.
In most cases, only one of the four ADAT CHANNEL buttons will
be lit, indicating the two channels on which an ADAT will transmit
or receive audio. If both the Source and Destination are set to
ADAT, all four ADAT CHANNEL buttons will be lit indicating that

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all eight channels of the ADAT digital bus are transferred.
When using the BRC Master Remote Control, any two channels can
be selected, in which case the ADAT CHANNEL button(s)
corresponding to each selected channel will be lit. Example: if the
BRC is used to select channels 2 and 5 as the ADAT channels, two of
the AI-1’s ADAT CHANNEL buttons (the 1/2 and 5/6 buttons) will
be lit indicating the groupings which contain the selected channels.
1.3D Destination Rate
The DESTINATION RATE buttons (48kHz and 44.1kHz) are used to
select the AI-1’s sample clock output. When one of these buttons is
pressed, its LED will be lit indicating it has been selected.
Only one of the two DESTINATION RATE buttons will be lit to
indicate the output sampling rate. The input rate is automatically set
to match that of the digital source (i.e. whatever rate the source uses,
the AI-1 will automatically detect it and adjust the sampling rate
accordingly).
Here are descriptions of the two Destination Rate possibilities:
•48kHz: If the source rate is 48kHz, this button’s LED will be lit
indicating the AI-1’s sample rate. If the source rate is 44.1kHz,
pressing the 48kHz button will convert the source’s sample rate
to 48kHz.
•44.1kHz: If the source rate is 44.1kHz, this button’s LED will be
lit indicating the AI-1’s sample rate. If the source rate is 48kHz,
pressing the 44.1kHz button will convert the source’s sample rate
to 44.1kHz.
Note: If the AI-1’s Destination is set to ADAT and the source’s
sample rate is 48kHz, you will not be able to select the 44.1kHz
button nor alter the AI-1’s output rate. This is because ADAT
already uses a 48kHz sample rate, which is of course superior to
44.1kHz.
If the source rate is neither 48kHz or 44.1kHz, the SOURCE button
LED corresponding to the source (ADAT, AES/EBU or S/PDIF) will
flash, and no sample rate conversion will be allowed. This will be

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indicated by the fact that both the 48kHz and 44.1kHz LEDs will be
turned off.

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CHAPTER 2: HOOKUP
2.0 POWER
The AI-1 works with any AC voltage from 90 to 250 volts, 50 to 60
Hz. This eliminates the need for transformers or voltage switches.
The AI-1 comes with a line cord for the destination to which the AI-
1 is shipped.
The AI-1’s IEC-spec AC cord (do not substitute any other AC cord)
is designed to feed an outlet that includes three pins, with the third,
round pin connected to ground. The ground connection is an
important safety feature designed to keep the chassis of electronic
devices such as the AI-1, BRC and ADAT at ground potential. Un-
fortunately, the presence of a third ground pin does not always
indicate that an outlet is properly grounded. Use an AC line tester to
determine this. If the outlet is not grounded, consult with a licensed
electrician. When AC currents are suspected of being highly
unstable in VAC and Hz, a professional power conditioner should
be used.
2.1 CONNECTION TO ADAT(S)
2.1A Single ADAT
To connect an Alesis AI-1 module, simply use two fiber optic cables
to connect the digital ins and outs back and forth between the AI-1
and the ADAT (see figure 1). It is not necessary to connect a sync
cable from the ADAT to the AI-1 (or vice-versa) since the ADAT will
provide the AI-1 with clock information via the optic digital
connection when outputting tracks to an AES/EBU or S/PDIF
destination, and the AI-1 will provide clock information to the
ADAT via the optic digital connection when recording from an
AES/EBU or S/PDIF source.
To connect the AI-1 to a single ADAT:
1. Connect one end of a fiber optic cable into the optic digital
output of the ADAT, and the other end to the AI-1’s “ADAT”

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optic digital input;
Note: If the other end of a fiber optic cable is disconnected and a
signal is being sent through the cable, you will be able to see a
red light at the output. This is an LED and not a laser light, so
you don’t have to worry about damage to your eyes.
2. Connect one end of a fiber optic cable to the AI-1’s “ADAT”
optic digital output, and the other end to the ADAT’s optic
digital input.
This last step creates a loop in the digital bus, and thus allows for
two-way communication between the ADAT and the AI-1.
Figure 1
2.1B Multiple ADATs without the BRC
When using two or more ADATs along with the AI-1, the setup is
basically the same as with a single ADAT, except you’ll need more
cables to accommodate a longer chain of devices (see figure 2). The
ADATs must be synchronized together, using dual male, 9-pin D
connectors. The AI-1 still uses fiber optic cables to connect to the
ADAT’s digital bus, but it does not require connecting the
synchronization cable, since all sync information is conveyed over
the fiber optic cable along with the digital audio.
You might decide to dedicate the AI-1 to just one of the ADATs by
connecting the fiber optic cables between them. This would,
however, limit you to only transmit/receive data between the AI-1
and only that one ADAT, and would prevent you from bouncing
tracks in the digital domain between that ADAT and the other
ADATs in your system. By the way, using a BRC solves all of these
problems.

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In the meantime, you may be tempted to reconnect the AI-1 to a
different ADAT when you want to route digital audio to tracks on
another machine. However, to avoid a lot of cable swapping, we
recommend swapping tapes instead. For example, let’s say you have
two ADATs, the AI-1 is connected to and from ADAT #1. When you
wish to record from an S/PDIF source onto tracks 9 and 10 (ADAT
#2), the best and quickest solution is to swap tapes between the two
ADATs and record onto tracks 1 and 2. During this time, any pre-
recorded tracks may appear on different channels of your mixer
(unless you have a sophisticated patch-bay system). But this is a
minor inconvenience that lasts only until you have finished
recording from the AI-1.
It is recommended that you use the BRC Master Remote Control if
you have a multiple ADAT system, due to greater flexibility in
digital routing. However, it is possible to incorporate the AI-1 into a
multiple ADAT system without the BRC.
To connect the AI-1 to a multiple ADAT system:
1. Connect one end of a shielded dual male, 9-pin D connector to
the first ADAT’s SYNC OUT jack, and connect the other end of
the cable to the SYNC IN jack of the second ADAT;
2. For each additional ADAT slave, connect one end of an
additional shielded dual male, 9-pin D connector to the second
ADAT slave’s SYNC OUT jack, and the other end to the third
ADAT slave’s SYNC IN jack. Its SYNC OUT jack then connects
to the fourth ADAT slave’s SYNC IN jack, and so on;
3. Connect one end of a fiber optic cable to the first ADAT’s
DIGITAL OUT, and connect the other end of the cable to the
DIGITAL IN of the second ADAT;
Note: If the other end of a fiber optic cable is disconnected and a
signal is being sent through the cable, you will be able to see a
red light at the output. This is an LED and not a laser light, so
you don’t have to worry about damage to your eyes.
4. For each additional ADAT slave, connect one end of an
additional fiber optic cable to the second ADAT slave’s DIGITAL

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OUT, and the other end to the third ADAT slave’s DIGITAL IN.
Its DIGITAL OUT then connects to the fourth ADAT slave’s
DIGITAL IN, and so on;
5. Connect one end of a fiber optic cable to the DIGITAL OUT of
the last ADAT in the chain, and connect the other end of the
cable to the AI-1’s “ADAT” optic DIGITAL IN;
6. Finally, connect one end of a fiber optic cable to the AI-1’s
“ADAT” optic DIGITAL OUT, and the other end to the optic
DIGITAL IN of the first ADAT in the system.
This last step creates a loop in the digital bus, and thus allows for
communication between all ADATs and the AI-1.
Figure 2
Note: In a multiple ADAT system, if power is turned off on one of
the ADATs in the middle of the chain, all ADATs following it
will no longer sync to the master ADAT, as the sync information
will not pass through a unit that is turned off.
2.1C Connecting the BRC
When using the BRC, the AI-1’s “ADAT” digital in and out connect
between the last ADAT and the first ADAT in the system. In order
for transfer of digital audio to be possible, the AI-1 requires
synchronization information from the BRC. Synchronization
requires a dual male, 9-pin D connector to connect the last ADAT in
the system to the AI-1. In addition, a BNC-type connector must be
used to connect the 48kHz word clock output of the AI-1 into the

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BRC. This is required so that the BRC can synchronize to an
AES/EBU or S/PDIF source. Both these connections can be made
while power is on or off, and the ADATs do not need to be turned
on in any particular order (see figure 3).
To connect the AI-1 to a BRC and a multiple ADAT system:
1. Connect one end of a shielded dual male, 9-pin D connector to
the SYNC OUT jack of the last ADAT in the system, and connect
the other end of the cable to the SYNC IN jack of the AI-1;
2. Connect one end of a BNC connector to the 48kHz OUT jack on
the AI-1, and connect the other end of the cable to the 48kHz IN
jack on the BRC;
3. Connect one end of a shielded fiber optic cable into the optic
DIGITAL OUT of the last ADAT in the system, and connect the
other end of the fiber optic cable to the AI-1’s “ADAT” optic
DIGITAL IN;
Note: If the other end of a fiber optic cable is disconnected and a
signal is being sent through the cable, you will be able to see a
red light at the output. This is an LED and not a laser light, so
you don’t have to worry about damage to your eyes.
4. Connect one end of a fiber optic cable to the AI-1’s “ADAT”
optic DIGITAL OUT, and the other end to the optic DIGITAL IN
of the first ADAT in the system.
This last step creates a loop in the digital bus, and thus allows for
communication between all ADATs and the AI-1.

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Figure 3
Note: In a multiple ADAT system, if power is turned off on one of
the ADATs in the middle of the chain, all ADATs following it
will no longer sync to the BRC, as the sync information will not
pass through a unit that is turned off.

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2.2 AES/EBU AND S/PDIF
2.2A Connecting an AES/EBU Device
Digital routing to and from an AES/EBU device requires XLR type
cables. These connections can be made while power is on or off, and
the components do not need to be turned on in any particular order.
To connect an AES/EBU device:
1. Connect one end of an XLR cable into the AES/EBU XLR output
of the AI-1, and the other end to the XLR input of the AES/EBU
device;
2. Connect one end of an XLR cable into the AES/EBU XLR output
on the device, and the other end to the AES/EBU XLR input of
the AI-1.
2.2B Connecting an S/PDIF Device
Digital routing to and from an S/PDIF device requires either fiber
optic cables or RCA cables, since the AI-1 provides both these
connectors. These connections can be made while power is on or off,
and the components do not need to be turned on in any particular
order.
To connect an S/PDIF device:
1. Connect one end of a fiber optic cable into the S/PDIF optic
output of the AI-1, OR, connect one end of an RCA cable to the
S/PDIF RCA output of the AI-1 (depending on which
connections are available on the S/PDIF device);
2. Connect the other end of the fiber optic cable to the optic input of
the S/PDIF device, OR, connect the other end of the RCA cable
to the RCA input of the S/PDIF device;
3. Connect one end of a fiber optic cable into the S/PDIF optic
output, OR, connect one end of an RCA cable to the RCA output
on the S/PDIF device;

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4. Connect the other end of the fiber optic cable to the S/PDIF optic
input, OR, connect the other end of the RCA cable to the RCA
input of the AI-1.
Note: Both the optic and RCA outputs are active when the AI-1’s
Destination is set to S/PDIF. This means you can route digital
audio to two S/PDIF devices simultaneously. When the AI-1’s
Source is set to S/PDIF, the RCA input has priority over the
optic input. If the AI-1 does not detect a device connected to the
RCA input (no sample clock present), it will automatically
switch over and use the optic input. Since the switch is
determined by the presence of a sample clock, you could leave a
device connected to the RCA input, and simply turn its power
off when you wish to use the optic input.
2.3 48 KHZ CLOCK OUT
The 48kHz output signal is a 75 TTL level square wave output,
and is provided via a BNC-type connector. If you are using the BRC
Master Remote Control and plan to record onto ADAT from an
AES/EBU or S/PDIF source, the 48kHz clock out must be connected
to the BRC so that it can be synchronized with the source’s clock
rate.
2.4 POWERING-UP
Normally, the AI-1 does not need to be powered up in any order for
it to work with one or more ADATs. The system can even be
connected while the power is on.
When using the BRC as the system’s master, however, the order in
which the devices are powered-up is important. After all
connections have been made, turn on the power of each ADAT in
the system, turn on the AI-1, and then turn on the BRC.
For more information on using the BRC, please refer to the BRC
Reference Manual.

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CHAPTER 3: TRANSFERRING
DIGITAL AUDIO
3.0 AI-1 TO ADAT
Recording from an AES/EBU or S/PDIF source through the AI-1
onto ADAT involves a few very simple steps. First, put the ADAT(s)
into Digital In mode by pressing the DIGITAL IN button (the button
will be lit). Next, the digital source must be selected. Then, choose
the tracks you wish to record to. Finally, adjust the sampling rate, if
necessary, to suit your needs.
3.0A Source
On the AI-1, you must set the source to either AES/EBU or S/PDIF,
depending on the actual source you are recording from. This is done
by pressing either the AES/EBU or S/PDIF button in the SOURCE
section of the AI-1 front panel. When pressed, the button will either
light solid or flash to indicate the source you have selected. Only
one of the Source buttons can be selected at a time.
•If the selected Source button’s LED lights solid, it means that an
AES/EBU or S/PDIF device is connected, and the AI-1 is
receiving its clock information. Simultaneously, either the 48kHz
or the 44.1kHz Destination Rate LED will light, indicating the
source’s incoming clock rate.
•If the selected Source button’s LED flashes, it means that either
no device is connected to the selected input, or the clock
information is not being provided by the source to the AI-1, or
the clock information provided by the source is neither 48kHz or
44.1kHz.
Note: If the Source button’s LED flashes, neither one of the
Destination Rate buttons will be lit, indicating that the AI-1 does
not detect any clock information from the source to synchronize
to.
Note: The AI-1 provides two types of connectors for S/PDIF devices.
When the Source is set to S/PDIF, the AI-1 will first look at the