Alesis ADAT User Manual

ALESIS

ADAT

"BLACK FACE"

Reference Manual

TABLE OF CONTENTS

CHAPTER 1: INTRODUCTION

1.0 ABOUT ADAT ....................................................................................5

1.2 IMPORTANT NOTE ABOUT THIS MANUAL ..................................9

1.3 OVERVIEW OF MAIN FUNCTIONS ...............................................10

1.3A Transport..............................................................................10

1.3B Record/Monitor functions ....................................................10

1.3C Punching..............................................................................10

1.3D Autolocation..........................................................................11

1.3E LED Indicators....................................................................11

1.4 “ENGAGED” VS. “DISENGAGED” TAPES.................................11

1.5 A WORD ON ADAT's S-VHS CASSETTE TAPE..........................12

1.6 OPERATING ENVIRONMENT........................................................13

1.6A Thermal Considerations in Rack Mounting..........................13

1.6B Mounting on a Shelf or Non-Rack Enclosure......................13

1.6C Avoiding Electromagnetic Interference...............................13

CHAPTER 2: HOOKUP

2.0 POWER.............................................................................................15

2.0A The AC Cord........................................................................15

2.0B Avoiding Ground Loops.......................................................16

2.1 AUDIO CABLE TIPS........................................................................17

2.2 AUDIO—UNBALANCED INPUTS..................................................18

2.2A Input Jack Characteristics ..................................................18

2.2B Typical Input Jack Hookups................................................19

2.2C Special Unbalanced Input Jack Wiring...............................19

2.3 AUDIO—UNBALANCED OUTPUTS..............................................20

2.4 AUDIO—BALANCED INPUTS AND OUTPUTS...........................21

2.5 DIGITAL I/O ......................................................................................21

2.6 SYNC.................................................................................................21

2.7 METER BRIDGE...............................................................................22

2.8 FOOTSWITCHES.............................................................................22

CHAPTER 3: GETTING READY TO RECORD

3.0 POWER-UP AND TAPE INSERTION.............................................23

3.1 FORMATTING A TAPE ...........................................................23

3.1A To Format A New Tape, or

Reformat/Erase an Old Tape..............................................24

3.1B To Extend a Format.............................................................25

3.1A Additional Format Considerations ........................................26

3.1B Record A “Benchmark” Tape..............................................27

3.2 TRACK RECORD/MONITOR CONTROLS....................................27

3.2A Record Enable Buttons .......................................................27

3.2B Auto Input Monitor................................................................27

3.2C All Input Monitor...................................................................29

3.2D Digital Input..........................................................................29

3.3 SETTING LEVELS............................................................................29

3.4 TRANSPORT CONTROL OPERATION.........................................31

3.4A Eject.....................................................................................31

3.4B Rewind.................................................................................31

3.4C Fast Forward.......................................................................31

3.4D Stop.....................................................................................32

3.4E Play.....................................................................................32

3.4F Record/Punch In or Out......................................................33

3.5 FOOTSWITCH-CONTROLLED PUNCHING ................................34

CHAPTER 4: PITCH, AUTOLOCATION, AND REMOTE CONTROLS

4.0 PITCH CONTROLS..........................................................................35

4.1 AUTOLOCATION CONTROLS.......................................................36

4.1A Setting Locations.................................................................36

4.1B Autolocating to One of the Three Location Points...............37

4.1C Shuttling Between Locate 1 and 2.......................................37

4.1D The Auto Play Function........................................................38

4.1E Record, Then Audition Your Part........................................38

4.2 FOOTSWITCH CONTROLLED AUTOLOCATION .......................38

4.3 USING THE LRC REMOTE CONTROL .........................................39

CHAPTER 5: MULTIPLE ADAT OPERATION

5.0 MULTIPLE ADAT BASICS41

5.1 SYNCHRONIZING MULTIPLE ADATS..........................................42

5.1A Hooking Up Multiple ADATs.................................................42

5.1B ADAT ID (Identification) Numbers.......................................42

5.1C How the Master and Slave Decks Interact.........................43

5.1D Achieving Lock.....................................................................44

5.1E Independent Slave Mode......................................................44

5.2 FORMATTING WITH MULTIPLE ADAT SYSTEMS......................44

5.2A Master Format Enabled and

Performing a Complete, Start-to-Finish Format...................44

5.2B Master Format Enabled and

Extending the Format...........................................................45

5.2C Master Format Disabled......................................................45

5.3 AUTO-LOCATION/LOOPING

WITH MULTIPLE ADATS ................................................................47

CHAPTER 6: BACKUP

6.0 BACKUP BASICS............................................................................49

6.1 BACKING UP VIA DIGITAL I/O......................................................49

6.1A Normal Method.....................................................................50

6.1B Optical-Only Method............................................................52

6.2 BACKING UP VIA ANALOG I/O.....................................................53

CHAPTER 7: APPLICATIONS

7.0 COMBINED MULTITRACK/ MASTERING DECK.........................55

7.1 ARCHIVING......................................................................................55

7.2 BOUNCING.......................................................................................56

7.3 LIVE RECORDING...........................................................................56

7.4 USING ADAT WITH MIDI SEQUENCERS

VIRTUAL TRACKING ......................................................................56

7.6 VIDEO LOCATION RECORDING...................................................57

7.7 MODULAR RECORDING57

CHAPTER 8: ADAT ADVANCED FEATURES

8.0 ABOUT THE ADVANCED FEATURES..........................................59

8.1 ADVANCED FEATURES 59

8.1A Eject the tape in the Master ADAT of a Multi

ADAT System.....................................................................60

8.1B Device Id.............................................................................60

8.1C Auto Input Monitor Option Select........................................60

8.1D Software Version.................................................................60

8.1E Tape Write Protect Status..................................................60

8.1F Monitor/Audio Path Select..................................................61

8.1G Crossfade Select...............................................................61

8.1H Digital 48k Master Clock Enable/Disable............................62

8.1I Total Running Time of Drum Motor......................................62

CHAPTER 9: MAINTENANCE/SERVICE

9.0 GENERAL INFORMATION63

9.0A Cleaning...............................................................................63

9.0B Maintenance.......................................................................63

9.0C Refer All Servicing to Alesis................................................63

9.1 ADAT HEAD LIFE............................................................................64

9.2 ADAT HEAD MAINTENANCE ........................................................64

9.3 TAPE MAINTENANCE - SAFE TAPE ............................................66

9.4 ERROR MESSAGES .......................................................................67

9.4A ADAT Messages and Explanation......................................68

9.4B Errors 1 to 9........................................................................69

9.4C Steps to Take Before Calling for Help................................71

CHAPTER 10: APPENDICES ..............................................................

10.0 APPENDIX 1

DIGITAL RECORDING—A QUICK TOUR.................................73

10.0A Analog Tape Recording Basics........................................73

10.0B Digital Tape Recording Basics........................................74

10.0C Why Does ADAT Use S-VHS Cassettes?......................74

10.1 APPENDIX 2

GLOSSARY..................................................................................76

10.2 APPENDIX 3

SPECIFICATIONS.......................................................................80

10.3 APPENDIX 4

SCHEMATICS..............................................................................83

CHAPTER 1: INTRODUCTION

1.0 ABOUT ADAT

Congratulations. You've just purchased an incredible piece of recording equipment.
Here are a few of the features that make the ADAT Digital Recorder perhaps one of
the most important advances in recording technology since the invention of multi­track. These features are of equal significance to the professional commercial studio
and the personal home or project studio:

• Low tape cost. ADAT records approximately 40 minutes of audio on a standard

S-VHS® tape cassette. This is the same tape that is used with S-VHS video tape
recorders. It's readily available and relatively low in cost for the purpose of multi­track recording. We chose S-VHS because the cassette shell, tape hubs and
guides are precision crafted in the S-VHS format to treat the tape gently and
interface in a precisely controlled manner with the ADAT transport over long
periods of recording. We recommend you always use S-VHS tape to protect your
valuable recordings. Your ADAT was packed with a complimentary Alesis S-VHS
Mastering Audio Cassette. It should perform to your highest expectations. You
can order more through your Alesis dealer or directly from Alesis. See the
accompanying flyer for information on how to order.

• Superb fidelity. ADAT uses 16-bit linear analog-to-digital conversion, the

professional standard 48 kHz sampling rate (variable from 40.4kHz to 50.85kHz),
and 64 times oversampling for better-than-CD quality sound.

• Ultra high fidelity digital converters. The digital converters in ADAT are the

latest generation in converter technology.

®

VHS is a registered trademark of JVC.

Because of the tremendous economies of scale realized in manufacturing ADAT,
these high quality and

more expensive converters are included in the ADAT design (rather than having to

be purchased as a separate accessory box as with some recorders) in spite of
ADATs low overall cost. This converter technology allows recording and
reproduction of the very highest quality. Plus, ADAT's design dedicates separate
converters to the inputs and outputs of each individual track. That's 16 converters
in all - no multiplexing.

• Easy and familiar front panel controls. If you've ever used a multitrack tape

recorder, then you probably already know how to use ADAT. Familiar controls
like play, record, fast forward, rewind, and track select buttons perform the major­ity of functions you'll need. There are no difficult engineering routines for you to
learn.

• Sample accurate syncing capabilities. ADAT was designed to work perfectly

as a stand-alone 8 track recorder and performs this function without equal. But
its design goes much further to include a built in synchronization system that
allows multiple ADATs to lock together in perfect synchronization; so, you can
expand the number of recording tracks and buy more ADATs as your budget
allows and your needs expand. Nothing in the system will become obsolete and
ADAT's modular standard is the key to compatability between your studio and
everyone else's; be it a home studio or fully professional commercial studio. You
might have purchased 3 or four ADATS and the optional BRC Remote Control for
a 24 or 32 track system, or you might even plan to build a large ADAT system of
up to 16 ADATS and the BRC- that's 128 tracks of digital audio! Multiple ADATs,
the BRC and other accessories (like the RMB Remote Meter Bridge) form what
we call the ADAT System.

Each ADAT tape is "formatted" (a simple operation that can be done before or
during recording) with a proprietary Alesis time code that is much more accurate
than SMPTE or other time code systems, and time-stamps the tape to an
incredible single-sample accuracy; that is, 1/48,000th of a second.

Why is this important? Because of such incredibly tight sync performance,
multiple ADATs are virtually free of the evils of incoherent phase between tracks
playing on different machines. This means that when you lock 2 or more ADATs
together, you're really creating the equivalent of one large digital tape recorder
and one very wide, seamless piece of tape.

And because ADAT's sync system is internalized and so accurate, you get
machine synchronization without giving up an audio track, accurate tape counter
readings without annoying slippage, and intelligent sample-accurate autolocation
functions with the BRC.

• Modular recording. This is the feature that makes ADAT and the ADAT System

perhaps the most flexible multitrack recorder ever designed. Because ADAT's S­VHS tape format is so inexpensive, you can easily record alternate versions of
vocals, solos, background accompaniments; whatever your creative urge
dictates.

Modular recording means you can build as many tracks as you desire while
you're recording and do composite editing with the BRC and ADAT's Optical
Digital Interface (see next section) before the final mixdown.

• Optical digital interface. In addition to conventional analog inputs and outputs, a

“master” digital I/O carries all eight tracks simultaneously via optical cable,
allowing for perfect, degradation-free digital dubbing between ADATs. And with
the addition of the optional BRC Remote Control, you can assign any part of any
track to any other track in a multiple ADAT system. This means you can do
complex composite editing. Like the chorus on track 2? Want to replace the cho­rus on track 15? Easy to do with the BRC carrying the timing and Sync

Information while the optical cable carries all the digital audio. The new chorus on
track 15 will be an exact digital duplicate of the one on track 2. Feel particularly
inspired one day, but can't make up your mind about which lead solo to go with?
Fill five or six tracks of a single S-VHS cassette tape with your hottest playing.
Take the best performance, or the best parts of each one and recompose the
entire solo on a new track. All in perfect sync, all sample accurate, all in the digital
domain. The popular recording practice of composite vocals is just as easy, and
more effective than ever with ADAT to support your efforts.

• AI-1 AES/EBU and S/PDIF Digital Interface with Sample Rate Converter. If

you need to integrate your ADAT recordings with digital recording equipment from
other manufacturers, an optional accessory box, the Alesis AI-1, can isolate the
digital audio signal 2 tracks at a time from the optical interface's 8-track data
stream, and assign that pair to the industry standard AES/EBU and S/PDIF
interfaces. This allows for direct digital connection, with sample rate conversion,
to and from other digital audio recorders, DAT recorders, CDs, hard disk
recorders, synthesizers, and more.

• LRC Remote Control. Each ADAT is supplied with the LRC Remote. This handy

device duplicates ADAT's front panel play, record, fast forward, rewind, stop and
3 point autolocate system. You can also control the monitor select functions.

• Highly sophisticated and comprehensive optional BRC Master Remote

Control. The BRC is the brains of the ADAT System. It supplies sophisticated
synchronization and overdubbing functions for multiple ADAT machines, remote
control of virtually all recorder functions, reads and generates SMPTE time code,
and generates MIDI Time Code (MTC) and MIDI clocks. The BRC can control up
to 16 ADATs for a total of 128 tracks of digital audio.

• RMB Remote Meter bridge option. When using the BRC in a multi-ADAT

system the RMB Remote Meter Bridge provides localized viewing of 32 channels
of LED meters. It's designed to mount on top of the BRC (or be rack mounted) so
that you can install your ADATs in a remote rack and control functions and view
critical metering of the recorders directly from one location.

• Easy interfacing with professional, project and home studios.

ADAT includes a balanced 56 pin ELCO connector for +4dBu interfacing, typical
in professional studios. For the home and project studio using -10 signals, ADAT
includes unbalanced -10dBV inputs and outputs on 1/4" jacks. For convenience,
the balanced and unbalanced inputs and outputs work simultaneously.

• Voltage-tolerant power supply. ADAT accepts any AC

voltage between 90 and 250 volts, without the need for external converters.

• Compatibility with multi-channel mixdown formats. ADAT

is ideal for quadraphonic, surround, and theatrical sound applications that require
more than two channels for the final master.

For more information on digital recording, see Appendix 1. Appendix 2 is a glossary
of digital recording-related terms that may be helpful as you read this manual.

1.2 IMPORTANT NOTE ABOUT THIS MANUAL

ADAT’s transparent user interface may tempt you to just plug in and start recording.
We can certainly understand your excitement, but please at least do the following:

• Read section 1.4 on the difference between “engaged” and

“disengaged” tapes, and section 3.1 on formatting tapes (with multiple ADAT
systems, also refer to section 5.2). These important sections describe recording
concepts that have no counterpart with analog recorders, and which must be
understood before you start using ADAT.

• Please read the entire manual at some point to acquaint yourself with the many

ADAT features that you’ll know about only if you read the manual.

1.3 OVERVIEW OF MAIN FUNCTIONS

Here is a brief rundown of ADAT’s main functions.

1.3A Transport

The transport is like most standard multitrack recorder transports. Tape motion
controls include play, fast forward, rewind, stop, record, and pause. The counter
shows elapsed time from the beginning of the tape, or the time from where you last
reset the zero counter.

1.3B Record/Monitor functions

ADAT does much of the recording/monitoring switching work for you. Generally,
tracks monitor what’s on tape until you initiate recording (typically by punching), at
which point any tracks set to record monitor the inputs so you can hear what’s being
recorded. For live multitrack recording, a special mode lets you monitor all eight
inputs regardless of record status.

The input jacks are wired using innovative switching techniques to allow for fast track
selection, patching, and track switching. Section 2.2C explains this in more detail.

1.3C Punching

Punch-in and punch-out are gapless and glitchless. Digital crossfades can be set to
any of four different crossfade times.

A user-supplied momentary footswitch allows for no-hands punch-in and out.
The BRC can do auto punch in and out referenced to sample-accurate loca­tion points.

1.3D Autolocation

You can set three autolocate points on the front panel or on the LRC Remote; simply
pressing a button will cause ADAT to seek and find the desired point. “Looping” is
also possible by shuttling between two locate points. An auto play feature can
automatically put ADAT into play mode when the autolocation operation is complete.

1.3E LED Indicators

In addition to specific LED indicators (such as those that indicate if a track is record­enabled), several switches have built-in LEDs. Sometimes these flash to indicate that
a function is ready to be initiated, then turn solid to indicate that the function is being
implemented. Most switches toggle, meaning that pressing once will turn a function
on, and pressing again will turn it off.

In this manual, LEDs are spelled with all capital letters (such as RECORD LED or
FORMAT LED).

1.4 “ENGAGED” VS. “DISENGAGED” TAPES

When you first insert an S-VHS tape cassette into ADAT,
a portion of the tape is pulled out of the tape cartridge and threaded against a rotating
head drum where the digital information is actually read and recorded in diagonal
scans across the tape. This is called engaged mode. Even when the tape itself is
stopped, it is still in contact with the head drum. If the STOP LED is lit solid, the tape
is engaged.

This allows for going into play or record faster, as well as “cue” and “review”
functions that let you monitor the tape audio during fast forward and rewind. When the
machine is paused, the head remains spinning, and the tape is not disengaged from
the head.

If you press the Stop button twice, the ADAT mechanism will unthread the tape and pull it
back into the S-VHS cassette. The STOP LED will blink to indicate that the tape is

disengaged.

When the tape is “disengaged,” the head is not spinning and it takes slightly longer to go
into play or record. Cue and review are no longer possible, but rewind and fast forward
speeds are much faster.
As a general rule, if you need to fast forward or rewind over a long length, disengage the
tape first; if you only need to fast forward or rewind a short distance, leave the tape
engaged.

If the tape is engaged, and no transport activity (play, record, rewind, etc.) occurs
within about 4 minutes, the tape will automatically disengage itself to minimize tape
wear.

1.5 A WORD ON ADAT’s S-VHS CASSETTE TAPE

• Use only premium quality, name brand S-VHS cassette tape in the ST-120 length.

Alesis cannot overstress the importance of this. We recommend using AMPEX 489
DM Digital Mastering Audio Tape, or Alesis ADAT Mastering Audio Cassettes.
Other acceptable brands include Maxell XR-S Black, JVC XZ, 3M Master
Broadcast and ASD 40+, and TDK SP Super Pro.

• We do not recommend that you use inexpensive,

budget VHS cassettes. While they may work technically, their unpredictable quality and less
than premium formulation could decrease the reliability of your recording. Don't trust your
music with anything less than premium S-VHS tape. Inferior tapes not only jeopardize the
recordings made on them, they may shed oxide and leave behind a coating of dirt that will
interfere with future recordings, even if you switch back to premium quality tape. Defective
tape may even clog the head, requiring service.

• Accidents can happen—so digital audio, like floppy disks and hard disks, should

be backed up to prevent loss. Back up your tapes to another ADAT using the
fiber optic digital connector (section 6.1).

• Treat your tapes as the precision, fragile components that they are. Do not

expose them to extremes of heat, cold, or humidity. Never place tapes near
magnetic fields (power amps, TVs, monitors, magnets, etc.), and handle tapes
gently.

1.6 OPERATING ENVIRONMENT

1.6A Thermal Considerations in Rack Mounting

ADAT can be mounted in an equipment rack (taking up 3 rack spaces) or placed on
a table or shelf. When you install it, keep in mind that heat is the major enemy of
electronic equipment. Please observe the following:

• ADAT is designed to perform properly over a range of ambient temperatures from

10° C to +40° C (50° F to 104° F), in up to 80% non-condensing humidity. These
are not absolute limits, but Alesis cannot guarantee that ADAT will meet its
published specs or remain reliable if operated outside of these ranges.

• Always allow adequate ventilation behind ADAT. Do not seal any enclosure that

holds ADAT. It is not necessary to leave an empty rack space above or below
ADAT unless it runs hot enough to affect equipment above or below it.

1.6B Mounting on a Shelf or Non-Rack Enclosure

To mount ADAT on a shelf or other flat surface, Alesis recommends using the
enclosed stick-on feet to avoid scratching the shelf’s surface with the deck’s bottom.

Please observe the general comments on thermal considerations given under
“Thermal Considerations in Rack Mounting” no matter where or how the deck is
mounted.

1.6C Avoiding Electromagnetic Interference

Like all tape machines, ADAT uses magnetic tape that can be sensitive to
electromagnetic interference. Generally this is not a problem, but avoid
mounting ADAT next to devices that generate strong magnetic fields such as
power amplifiers, monitors and video display devices, speakers, etc.

CHAPTER 2: HOOKUP

2.0 POWER

2.0A The AC Cord

ADAT works with any AC voltage from 90 to 250 volts, 50 or 60 Hz. ADAT comes
with a line cord suitable for the destination to which ADAT is shipped.

Your ADAT was supplied with the correct power cord for your country or local area,
however only the following alternative power cords are approved for use with ADAT:

• For 90-120 VAC 50/60 Hz operation in the US, Canada and/or Japan, use Alesis

UL/CSA power cord #7-41-0001.

• For 240 VAC 50 Hz operation in England, use Alesis Power cord #7-41-0004.

• For 220 VAC 50 Hz operation in Europe and Scandinavia, use Alesis EU power

cord #7-41-0002.

• For 240 VAC 50 Hz operation in Australia, use Alesis AS power cord #7-41-0003.

ADAT’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 ADAT at ground potential. Unfortunately, the presence of
a third 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 power is suspected of being unstable a professional power
conditioner should be used.

DO NOT OPERATE ANY ELECTRICAL EQUIPMENT WITH UNGROUNDED
OUTLETS. PLUGGING ADAT INTO AN UNGROUNDED OUTLET, OR
“LIFTING” THE UNIT OFF GROUND WITH A THREE-TO-TWO WIRE
ADAPTER, CAN CREATE A HAZARDOUS CONDITION. ALESIS CANNOT BE
RESPONSIBLE FOR PROBLEMS CAUSED BY USING ADAT OR ANY
ASSOCIATED EQUIPMENT WITH IMPROPER AC WIRING.

2.0B Avoiding Ground Loops

In today’s studio, where it seems every piece of gear has a computer in it, there are
many opportunities for ground loop problems to occur. These show up as hums,
buzzes, or sometimes radio reception and can occur if a piece of equipment “sees”
two or more different paths to ground, as shown below.

One path goes from device A to ground via the ground terminal of the three­conductor AC power cord, but A also sees a path to ground through the shielded
cable and AC ground of device B. Because ground wires have a small amount of
resistance, small amounts of current can flow through ground and generate a voltage
along the cable shield. This signal may end up getting induced into the hot conductor.

The loop can also act like an antenna into which hum is induced, or can even pick up
radio frequencies. Furthermore, many components in a circuit connect to ground. If
that ground is “dirty” and contains noise, it might get picked up by the circuit. Ground
loops cause the most problems with high-gain circuits, since massive amplification of
even a couple millivolts of noise can give an audible signal.

Most ground loop problems can be solved by plugging all equipment into the same
grounded AC source. However, it is important to make sure that the AC source is not
overloaded and is properly rated to handle the gear plugged into it.

For really tough cases, you may need to break the connection that causes the loop
condition. One way to do this is to simply break the shield of the shielded audio
cable at some point, usually by disconnecting it from ground at one jack. (The other
end should remain connected so that the shielding properties are retained, even if
there is no direct path for ground.)

Please note that not all hums and buzzes are caused by ground loops; your cables
must be of very high quality, particularly with -10 dBV setups. Refer to section 2.1 for
more information.

2.1 AUDIO CABLE TIPS

The connections between ADAT and your studio are your music’s lifeline, so use
only high quality cables. These should be low-capacitance shielded cables with a
stranded (not solid) internal conductor and low-resistance shield. Although quality
cables cost more, they do make a difference. Route cables to ADAT correctly by
observing the following precautions.

• Do not bundle audio cables with AC power cords.

• Avoid running audio cables near sources of electromagnetic interference.

• Do not place cables where they can be stepped on. Although stepping on a cable

may not cause immediate damage, it can compress the insulation between the
center conductor and shield (thus degrading performance) or reduce the cable’s
reliability.

• Avoid twisting the cable or having it make sharp turns.

• Never unplug a cable by pulling on the wire itself. Always unplug by firmly

grasping the body of the plug and pulling directly outward. If you experience
difficulty in removing the plug, sometimes a slight rotating motion while unplugging
will solve the problem.

• Keep the cable contacts clean at all time. Oxidation may lead to intermittent

contacts, degraded sound quality, or even distortion. DO NOT USE AN
ABRASIVE TO CLEAN A DIRTY PLUG. This may remove some of the plug’s
conductive plating. Instead, spray contact cleaner on a clean, lint-free cloth and
vigorously rub the plug until the oxidation is gone.

2.2 AUDIO—UNBALANCED INPUTS

2.2A Input Jack Characteristics

ADAT includes eight unbalanced, 1/4” phone jack inputs. These are compatible with
the low-impedance, unbalanced, -10 dBV outputs typically emanating from equipment
such as mixers, synthesizers, samplers, direct boxes, etc. Guitars, microphones,
and other low-level/high-impedance output devices require a preamp or should be
routed through a mixer with mic preamps.

The unbalanced input jack wiring convention is:

• Tip: signal hot

• Sleeve: shield and ground

2.2B Typical Input Jack Hookups

The input jacks are typically hooked up in one of three ways:

• To the console’s direct tape outs (these patch a single channel directly to

tape, bypassing most mixer circuitry). This is preferred when the signals going
to tape require none of the mixer’s features (effects, grouping, routing, etc.).

• To eight mixer bus outputs. You can use the mixer for grouping, premixing,

effects, etc. This puts more circuitry between the input signals and ADAT,
although since most routing can be done at the mixer, you’ll seldom need to do
any repatching.

• To a combination of direct outputs and bus outputs. Some situations require

a combination of the two approaches. Example: Consider a live gig you want to
record with two vocal mics, four mics on drums, two direct feeds from guitar and
bass amps, and one direct feed from keyboards. The vocals, bass, guitar, and
keyboards could be taken direct and go to five ADAT tracks. The four drum mics
can be mixed to stereo within your mixer sent to the submix outs, then go to two

ADAT tracks. The remaining ADAT track could be used to record audience
sounds or capture one of the instruments in stereo, if applicable.

2.2C Special Unbalanced Input Jack Wiring

ADAT has a switched-jack wiring scheme that makes it possible to use an ADAT
even with a 2-output mixer.

Jacks 1, 3, 5, and 7 are normalled together, as are jacks 2, 4, 6, and 8. Anything
plugged into input 1 also feeds inputs 3, 5, and 7; anything plugged into input 2 feeds
inputs 4, 6, and 8. However,

plugging into any input interrupts the normalization, letting you use that jack by itself.
Example: With plugs inserted into inputs 1 and 5, the signal at input 1 also appears at
inputs 3 and 7. Input 5’s signal appears only at input 5.

This means that the buss outputs of a two buss board could be plugged into inputs 1
and 2 and routed to track pairs 1-2, 3-4, and 5-6 on multiple passes without
repatching cables by engaging the record enable switches for the desired tracks.
(On the first pass, enable record on tracks 1-2, on the second, 3-4, and so on). The
same applies for a four buss board. The first pass could be routed to tracks 1-4, and
the second to tracks 5-8. Using this technique will allow you to selectively route
signal to ADAT tracks using only ADAT's record enable buttons and your mixing
board's buss assigns.

Note that the unbalanced inputs and balanced inputs can be used simultaneously, but
the jack normalling feature is available only on the unbalanced 1/4" phone jack
inputs.

2.3 AUDIO—UNBALANCED OUTPUTS

The -10 dBV outputs use mono 1/4” phone jacks, and carry signals at a nominal -10
dBV level. These usually drive mixer
channel inputs or tape returns. They can be used at the same time as the balanced
outputs.

2.4 AUDIO—BALANCED INPUTS AND OUTPUTS

For convenience, ADAT includes +4 dBu balanced line inputs and outputs on a rear­panel multipin connector. Remember, the unbalanced and balanced inputs/outputs
are available simultaneously. (For diagram see Section 9.3 - Appendix 4)

2.5 DIGITAL I/O

The digital I/O connector follows a proprietary Alesis format that carries all eight
outputs on a single fiber optic cable . In conjunction with the BRC Remote Control the

Digital I/O is a very powerful feature that allows you to perform complex assembly
editing, fly parts from one ADAT to another, etc. all in the digital domain and without
any signal degradation. Also, the optional AI-1 ADAT AES/EBU Interface can use
this signal to provide AES/EBU and S/PDIF standard digital inputs and outputs. Refer
to the AI-1 manual for more information.

Since the fiber optic connector carries the digital information for all 8 tracks of the
ADAT it is also useful for backing up all tracks in one pass (section 6.1). You may
increase the pitch control to maximum (section 4.0) to speed up this process
somewhat.

2.6 SYNC

To sync together two or more ADATs, connect the Sync Out from the master to the
next ADAT’s Sync In. Its Sync Out can in turn feed a third ADAT’s Sync In, etc. This
requires a shielded dual male, 9-pin D connector cable available at your Alesis
dealer. For more information on syncing ADATs together, see Chapter 5.

2.7 METER BRIDGE

To connect ADAT to the Alesis RMB Remote Meter Bridge, run a dual male, 9-pin D
connector cable from the ADAT Meter Bridge out connector to the RMB input
connector.

2.8 FOOTSWITCHES

Any momentary single-pole/single-throw footswitch, normally open or normally
closed, will work for the two footswitch functions. These should be plugged in prior to
power-up so that ADAT can configure itself for the type of footswitch being used.

CHAPTER 3: GETTING READY TO RECORD

3.0 POWER-UP AND TAPE INSERTION

After all connections are made, turn on power. ADAT first checks whether a tape has
been inserted.

• If a formatted tape is present, the counter shows the elapsed time since the

beginning of the tape.

• If an unformatted tape is present, the counter will show “noFO,” and the FORMAT

LED will flash to indicate that the tape needs formatting. At this point you should
format the tape (see next section).

• If there is no tape, the counter shows "----" to indicate no tape is present.

Insert the end with the hinged door first, label side up, until you
encounter a slight bit of resistance. Push gently on the center of the cassette until
ADAT draws the tape inward. Once ADAT has started to pull in the tape, do not keep
pushing the tape in.

Note: to record on a S-VHS cassette, the write protect tab (located on the spine of
the cassette) must be intact. If you try to record on a tape that has had the write
protect tab broken off, the display will read "Prot" and the ADAT will not record on the
tape. This allows you to prevent accidental erasure of valuable recordings. To
record on a tape that has had the tab broken off, simply use a piece of scotch tape,
label, etc. in place of the write protect tab to completely cover the hole in the
cassette's spine.

3.1 FORMATTING A TAPE

Just as formatting a floppy disk lets a computer know where to place data, formatting
an ADAT tape time-stamps the tape to single-sample accuracy so that audio is
referenced to an accurate time base. This allows for simplified synchronization,
accurate tape counter readings, and intelligent autolocation with the BRC Remote
Control.

When formatting begins, ADAT writes some setup data during the first two minutes
and 15 seconds of tape, then at time -00:05, writes the time in minutes and seconds
onto a special sync track. This does not use up any of the eight audio tracks. Please
note: The display shows timings with a period separating the hours and minutes
(00.00), but this manual shows a colon instead of a period for clarity (00:00).

3.1A To Format A New Tape, or Reformat/Erase
an Old Tape

• It is a good practice to "exercise" the tape before

formatting it by fast forwarding it to the end, then rewinding it back to the lead. This evens out
the tape pack and relieves any stresses and strains that may have occurred during tape
manufacture and storage.

1 Press the Format button (if the tape was unformatted, the FORMAT LED will

have been flashing prior to pressing it). Once pressed, the FORMAT LED glows
steadily to indicate that formatting will begin if ADAT enters record mode. Also, all
eight track RECORD LEDs will flash to indicate all eight tracks will be recorded.
Pressing the eight record buttons has no effect while the FORMAT LED is lit
steadily.

2 Press Record and while holding it down, press Play. ADAT briefly enters play

mode to achieve proper speed and check if the tape is formatted.

3 If the tape is at the very beginning, ADAT performs a complete format by

recording 15 seconds of leader (display shows “LEAd”), two minutes of data
(display shows “dAtA”), then time code starting at -00:05 and continuing to the
end of the tape.
If an unformatted tape is not at the very beginning, then format is disabled and no
recording will take place. Be sure to rewind to the beginning of the tape before
formatting it for the first time.

3.1B To Extend A Format

Sometimes, you may not have time to format an entire 40-minute tape before using it,
although this is the best practice. This results in a tape that is only partially
formatted. For example, you may record only one song which ends four minutes into
the ADAT tape. If you want to use the rest of the tape, you must perform a format
extension. Play or fast forward the tape to just before the end of the previously
formatted section, and enter Format mode. Everything on the tape will be erased
from that point on. ADAT reads the sample-accurate time code of the original format
and begins formatting starting from that time onward, thus ensuring continuous time­stamping when a tape plays from beginning to end.

For this reason, if you plan to extend a format, don't press Stop immediately at the
end of the song when formatting. Leave a "buffer" of 15 seconds so you won't erase
the last note of the previous song when you extend the format for the next one.