Apogee BIG BEN User manual

192k Master Digital Clock
User’s Guide
v1.0 - June 2003

192k Master Digital Clock
User’s Guide
v1.0 - June 2003

APOGEE ELECTRONICS
ii
BIG BEN – User’s Guide
APOGEE ELECTRONICS iii
BIG BEN – User’s Guide
Warnings
FCC warning
This equipment has been tested and found to comply with the limits for a Class A digital device, pursu-
ant to Part 15 of the FCC rules. These limits are designed to provide reasonable protection against
harmful interference when operated in a commercial environment. This equipment generates, uses,
and can radiate radio frequency energy and, if not installed and used in accordance with the instruc-
tion manual, may cause harmful interference to radio communications. Operation of this equipment in
a residential area is likely to cause harmful interference, in which case the user will be required to take
whatever measures necessary to correct the interference at his own expense.
Copyright Notice
The Apogee BIG BEN is a computer-based device, and as such contains and uses software in ROMs.
This software, and all related documentation, including this User’s Guide contain proprietary informa-
tion which is protected by copyright laws. All rights are reserved. No part of the software and its related
documentation may be copied, transferred, or modied. You may not modify, adapt, translate, lease,
distribute, resell for prot or create derivative works based on the software and its related documenta-
tion or any part thereof without prior written consent from Apogee Electronics Corporation, U.S.A.

APOGEE ELECTRONICS
ii
BIG BEN – User’s Guide
APOGEE ELECTRONICS iii
BIG BEN – User’s Guide
Registration and Warranty Information
Be sure to register your BIG BEN, either by lling in the enclosed Registration Card or by completing
the on-line registration form at our Web site: http://www.apogeedigital.com/register.html. If you
do so, Apogee can contact you with any update information. As enhancements and upgrades are
developed, you will be contacted at the registration address. Firmware updates are free for the rst
year of ownership unless otherwise stated. Please address any inquiries to your dealer or directly to
Apogee at:
APOGEE ELECTRONICS CORPORATION,
3145 Donald Douglas Loop South, Santa Monica, CA 90405, USA.
TEL: [phone], FAX: [phone]
email: [email protected]. Web: http://www.apogeedigital.com/
APOGEE ELECTRONICS CORPORATION warrants this product to be free of defects in material and
manufacture under normal use for a period of 12 months. The term of this warranty begins on the
date of sale to the purchaser. Units returned for warranty repair to Apogee or an authorized Apogee
warranty repair facility will be repaired or replaced at the manufacturer’s option, free of charge.
ALL UNITS RETURNED TO APOGEE OR AN AUTHORIZED APOGEE REPAIR FACILITY MUST
BE PREPAID, INSURED AND PROPERLY PACKAGED, PREFERABLY IN THEIR ORIGINAL BOX.
Apogee reserves the right to change or improve design at any time without prior notication. Design
changes are not implemented retroactively, and the incorporation of design changes into future units
does not imply the availability of an upgrade to existing units.
This warranty is void if Apogee determines, in its sole business judgment, the defect to be the result
of abuse, neglect, alteration or attempted repair by unauthorized personnel.
The warranties set forth above are in lieu of all other warranties, expressed or implied, and Apogee
specically disclaims any and all implied warranty of merchantability or of tness for a particular
purpose. The buyer acknowledges and agrees that in no event shall the company be held liable for
any special, indirect, incidental or consequential damages, or for injury, loss or damage sustained by
any person or property, that may result from this product failing to operate correctly at any time.
USA: Some states do not allow for the exclusion or limitation of implied warranties or liability for
incidental or consequential damage, so the above exclusion may not apply to you. This warranty
gives you specic legal rights, and you may have other rights which vary from state to state.
Service Information
The BIG BEN contains no user-serviceable components: refer to qualied service personnel for repair
or upgrade. Your warranty will be voided if you tamper with the internal components. If you have any
questions with regard to the above, please contact Apogee.
In the event your BIG BEN needs to be upgraded or repaired, it is necessary to contact Apogee prior
to shipping, and a Return Materials Authorization (RMA) number will be assigned. This number will
serve as a reference for you and helps facilitate and expedite the return process. Apogee requires
that shipments be pre-paid and insured — unless otherwise authorized in advance.
IMPORTANT: ANY SHIPMENT THAT IS NOT PRE-PAID OR IS SENT WITHOUT AN RMA
NUMBER WILL NOT BE ACCEPTED.

APOGEE ELECTRONICS
iv
BIG BEN – User’s Guide
APOGEE ELECTRONICS v
BIG BEN – User’s Guide
Declarations of Conformity
Declaration of Conformity—FCC
Apogee BIG BEN
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and
(2) This device must accept any interference received, including interference that may cause undesired operation.
This equipment has been tested and found to comply with the limits of a Class B digital device, pursuant to Part
15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful inteference in a
residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed
and used in accordance with the instructions, may cause harmful interference to radio communications. If this
equipment does cause harmful interference to radio or television reception, which can be determined by turning
the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following
measures:
1. Re-orient or relocate the receiving antenna.
2. Increase the separation between the equipment and receiver.
3. Connect the equipment into an outlet on a different circuit from that to which the receiver is connected.
4. Consult the dealer or an experienced radio/TV technician for help.
NOTE: The use of non-shielded cable with this equipment is prohibited.
CAUTION: Changes or modications not expressly approved by the manufacturer responsible for compliance
could void the user’s authority to operate the equipment.
Apogee Electronics Corporation, 3145 Donald Douglas Loop South, Santa Monica, CA 90405.
Betty Bennett, CEO.
Industry Canada Notice
This Class B digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regula-
tions. Cet appareil numérique de la classe B respecte toutes les exigences du Règlement sur le matérial brouilleur
du Canada.
Declaration of Conformity – CE
Apogee Electronics Corporation hereby declares that the product, the BIG BEN, to which this declaration relates,
is in material conformity with the following standards or other normative documents:
• EN50081-1/EN55022; 1995
• EN50082-1/IEC 801-2, 3, 4; 1992
following the provisions of:
• 73/23/EEC – Low Voltage Directive
• 89/336/EEC – EMC Directive
Declaration of Conformity – Japan
Apogee Electronics Corporation hereby declares that the BIG BEN, to which this declaration relates, is in material
conformity with the VCCI Class A standard.
Declaration of Conformity – Australia
Apogee Electronics Corporation hereby declares that the BIG BEN is in material conformity with AN/NZS standard
requirements.

APOGEE ELECTRONICS
iv
BIG BEN – User’s Guide
APOGEE ELECTRONICS v
BIG BEN – User’s Guide
OWNER’S RECORD
The serial number is located on the rear panel of the unit. We suggest you record the
serial number in the space provided below. Refer to it whenever you call an authorized
Apogee Electronics repair facility or the manufacturer. Please be sure to return your com-
pleted warranty card immediately!
BIG BEN Serial No.
Purchase Date
Factory Firmware Revision
Dealer
Phone
Address
User’s Installation Notes:
CAUTION:
Any changes or modications not expressly approved by APOGEE ELECTRONICS
CORPORATION could void your authority to operate this equipment under the FCC rules.

......................................................................................................2
................................................................................3
.....................................................................................3
........................................................................................................3
..................................................................................................3
......................................................................4-9
............................................................................................4
.......................................................................................................4
............................................................................................5
.............................................................................................6
..........................................................................................6
.......................................................................................................7
...........................................................................................................7
.................................................................................8
................................................................................................8
................................................................................................9
..........................................................................9
...............................................................10
...........................................................................................10
.......................................................................................10
.......................................................................................10
....................................................................................10
.......................................................................................10
......................................................................10
........................................................................10
......................................................................................................10
....................11
.............................................................................................11
.................................................................................12
.............................................13-14
.....................................................................15
Table of Contents
Introduction
Getting Started Quickly
Connecting Power
Reset
QuickStart
Navigating the Front Panel
Power Switch
Set-Up
Clock Source
Sample Rate
Lock indication
Optical
AES
Pull Up/Down (VSO)
WC OUT 5
WC OUT 6
WC OUT/TERMINATION
Connections on the Rear Panel
AES IN 1 & 2
AES OUT 1 & 2
S/PDIF IN/OUT
OPTICAL IN/OUT
OPTION CARD
VIDEO/WORD CLOCK IN
WORD CLOCK OUT 1-6
AC IN
About Digital Audio Formats and Format Conversion
About SureLock
Internal Adjustments
Clock Distribution –Theory and Practice
Features and Specications
User’s Guide

APOGEE ELECTRONICS
2
BIG BEN – User’s Guide
APOGEE ELECTRONICS 3
BIG BEN – User’s Guide
Introduction
Apogee Electronics’ Big Ben Master Digital Clock provides a complete clock synchronization solution for
the digital production studio. Each feature of Big Ben has been carefully designed to ensure the highest
quality, stability and simplicity when synchronizing your studio.
• At the heart of Big Ben, Apogee’s C777 Clock Technology uses Direct Digital Synthesis to
generate ultra-stable clock frequencies whose jitter is virtually un-measurable regardless of
the clock source. Big Ben operates at frequencies up to 192 kHz, including common pull up/
pull down frequencies and VSO (varispeed) functionality.
• Adaptive Loop Filtering (ALF) optimizes clock performance and attenuates jitter, so that even
poor reference clock sources won’t degrade Big Ben’s performance.
• A wide range of input and output connections simplies studio conguration; included are
AES, S/PDIF and Optical I/O, plus 6 Word Clock outputs and 1 Word Clock/Video input. An
Option Card slot, for “emerging” digital formats such as FireWire, offers the ability to update
Big Ben’s functionality. Format conversion is available between AES, S/PDIF, Optical and
Option formats.
• Sure Lock ensures a fail safe lock to external sources, thereby stabilizing the entire clock
conguration. Word Clock termination sensing veries that all Word Clock connections are
properly terminated, thus avoiding transmission mis-matches which lead to hard-to-nd
clocking errors.
Please register this unit by lling in the included registration card, or registering online at
http://www.apogeedigital.com/register.html
Please read this manual – if you call for technical support, we’ll assume that you have. There will be a quiz.

APOGEE ELECTRONICS
2
BIG BEN – User’s Guide
APOGEE ELECTRONICS 3
BIG BEN – User’s Guide
USING THIS MANUAL
While the regularly scheduled manual runs
in the adjacent text, in-depth explanations,
operational warnings and other digressions
will be presented in these columns.
In this manual, “parameters” are dened
as the characteristics of operation, such as
CLOCK SOURCE or AES format, and are
capitalized in this manner :
CLOCK SOURCE.
“Values” are dened as the choices
available for each parameter – for
example, the parameter CLOCK SOURCE
has the values INTernal, AES1,
AES2,OPTICAL,OPTION,WC and VIDEO.
Values are italicized in this manner:
S/PDIF.
“Settings” are dened as the entire set of
parameters and values.
When physical controls such as buttons or
switches are referred to in the text, they are
highlighted in this manner: DOWN.
SYMBOLS:
The exclamation mark alerts
the user to potential pitfalls
of operation.
The musical note indicates
in-depth explanations.
Getting Started Quickly
CONNECTING POWER
Big Ben performs best when connected to AC power, and will accept
an AC input of 100 to 240 VAC at a frequency of 50 to 60 Hz. In
other words, Big Ben may be connected to virtually any AC power
outlet found worldwide without concern for voltage settings or fuse
ratings.
RESET
To reset the Big Ben, power up the unit while pressing the DOWN
key. This provides a quick method to return to factory default set-
tings when exploring the unit’s functionality and capabilities.
QUICKSTART
Follow these simple steps to get clocking quickly:
1) Reset Big Ben by powering up the unit while pressing the
DOWN key. This will congure the unit as shown at the top
of this page.
2) Congure Big Ben to the desired settings by following these
steps:
• Enable Setup mode by pressing any of the 4 SETUP buttons.
The SET UP LED will illuminate and the active parameter will
blink for a few seconds.
• Choose the parameter to be modied by pressing either
the PREV or NEXT button. Scroll through the 7 parameter
choices a few times to get a “feel” for choosing the desired
parameter.
• Modify the selected parameter to the desired value by press-
ing either the UP or DOWN button. Again, scroll through the
available values.
• If no buttons are pushed for 2 seconds, Setup mode is auto-
matically disabled.

APOGEE ELECTRONICS
4
BIG BEN – User’s Guide
APOGEE ELECTRONICS 5
BIG BEN – User’s Guide
It’s Got a Mind of Its Own!
As Big Ben’s settings are modi-
ed, certain parameters and
values become unavailable for selec-
tion, while others seem to change all by
themselves! In fact, Big Ben intelligently
modies many settings according to the
conguration of the unit. For example,
when an external CLOCK SOURCE is
selected, SAMPLE RATE can’t be modi-
ed, as its value is determined from the
selected CLOCK SOURCE. As another
example, the VSO value may be selected
only when CLOCK SOURCE is set to
INTernal.
Keep in mind that before
modication of any Big Ben
setting, SETUP mode must
be enabled.
Navigating the Front Panel
1 2
1) Power Switch – Every aspect of Big Ben has been carefully
thought out – even the Power Switch! Three congurations, set with
internal jumpers, are available:
1) Big Ben is powered on in the expected manner, by pushing the
Power Switch;
2) Big Ben powers on automatically when AC input is applied, but
the Power Switch is still functional;
3) the Power Switch is completely disabled.
Please see the section on “Internal Adjustments” for instructions
on changing the Power Switch mode.
Note that the Power Switch LED indicates that Big Ben is receiv-
ing a proper AC input, and is in Standby mode. The LED goes
out when Big Ben is powered on.
2) Set-Up buttons and LED – These buttons are used to modify
all settings on Big Ben. In general, setting modication requires 4
steps: enabling Setup mode, choosing the parameter to be modied;
choosing the desired value and disabling Setup mode.
1) Enable Setup mode by simply pressing any of the SETUP but-
tons. The SETUP LED will illuminate and the value selected the
previous time SETUP mode was enabled will blink.
2) Press either the PREV or NEXT buttons until the current value of
the parameter to be modied is blinking.
3) Press either the UP or DOWN buttons until the desired value is
blinking.
4) If no buttons are pushed for 2 seconds, Setup mode is disabled
automatically, and the value which was blinking will now illumi-
nate solidly. All settings (except some VSO settings) are saved in
non-volatile memory, and will be recalled the next time Big Ben is
powered up.

APOGEE ELECTRONICS
4
BIG BEN – User’s Guide
APOGEE ELECTRONICS 5
BIG BEN – User’s Guide
3) CLOCK /Digital Audio SOURCE – At it’s simplest, Big Ben
derives a reference clock frequency from an internal or external
source and generates several ultra low jitter clock outputs based on
this reference. The CLOCK SOURCE parameter selects the source
of the reference clock frequency. When a Clock Source is selected
which contains a digital audio signal, that signal is routed to all out-
puts capable of transmitting digital audio. The following sources are
available:
• INT – Big Ben’s clock outputs are derived from an internal clock
frequency generator. CLOCK SOURCE must be set to INTernal
to set the PULL UP/DOWN parameter to VSO,
• AES1 – clock and digital audio outputs are derived from the AES1
input. If AES is set to DOUBLE, both AES1 and AES2 will light.
• AES 2 – clock and digital audio outputs are derived from the
AES2 input.
• S/P COAX – clock and digital audio outputs are derived from the
S/PDIF coaxial input.
• OPTICAL - clock and digital audio outputs are derived from the
Optical input.
• OPTION - clock and digital audio outputs are derived from the
Option Card input. This selection is only available when an Op-
tion Card is installed.
• WC - clock outputs are derived from the Video/Word Clock input
when a valid word clock signal has been connected.
• VIDEO - clock outputs are derived from the Video/Word Clock
input when a valid video signal has been connected. The video
format (PAL,NTSC or B&W) will be automatically detected.
Navigating the Front Panel - continued
When video has been selected
as the clock source, allow Big
Ben approximately 30 seconds
to achieve the best lock.
3

APOGEE ELECTRONICS
6
BIG BEN – User’s Guide
APOGEE ELECTRONICS 7
BIG BEN – User’s Guide
Navigating the Front Panel - continued
The better the input reference
signal, the smaller the phase
differences between that input
and Big Ben’s ultra-stable output . If
these phase differences are less than 1
degree (as depicted in FIGURE 1), the
NARROW and WIDE LEDs light. If, on
the other hand, these phase differences
increase to a point where a loss of lock
may occur (as depicted in FIGURE 2),
the Narrow LED will extinguish, leaving
only the WIDE LED lit. Though Big Ben’s
output will remain remarkably stable, loss of
NARROW lock indicates a stability problem
with the input reference signal, caused by
excessive jitter or electrical failure.
Note that Apogee’s use of
Wide and Narrow terminology
differs from that of other
manufacturers, who use “narrow” to
designate a clock reference running
precisely at standard rates, and “wide”
to designate a clock reference running at
any varispeed rate.
4) SAMPLE RATE – When CLOCK SOURCE is set to INTernal or
VIDEO, SAMPLE RATE displays the frequency of the internally gen-
erated clock, and may be set to a frequency of 44.1 -192 kHz.
When CLOCK SOURCE is set to any other value (AES1, AES2, S/P
COAX, OPTICAL, OPTION or WC), SAMPLE RATE displays the
frequency detected at the selected input.
5) Lock Indication LEDs – Big Ben’s lock status to the selected
CLOCK SOURCE is indicated with a group of 5 LEDs; the following
states are indicated:
• Blinking Green Arrow – Big Ben is not locked to the selected
CLOCK SOURCE.
• Solid Green Arrow + “WIDE LOCK” displayed – Big Ben is locked
to the selected CLOCK SOURCE, but the quality of the input
signal is questionable.
• Solid Green Arrow + Blue Dot + “NARROW LOCK” displayed
– Big Ben has achieved the most precise lock possible.
• Blinking Green Arrow + Blue LED solidly lit – Big Ben is no
longer locked to the selected CLOCK SOURCE (indicated by
the Blinking Green Arrow) but has entered Surelock mode and is
transmitting a stable clock nevertheless (indicated by the solidly
lit Blue LED.
5
4





 






 



 





 







 




 
FIGURE 1
FIGURE 2

APOGEE ELECTRONICS
6
BIG BEN – User’s Guide
APOGEE ELECTRONICS 7
BIG BEN – User’s Guide
Navigating the Front Panel - continued
6) OPTICAL – This parameter determines the format of the Optical
Input/Output connectors.
7) AES - This parameter determines the format of the AES Input/
Output connectors.
Valid settings of the OPTICAL and AES parameters are determined
by the SAMPLE RATE as depicted in FIGURE 3 below;
192/176.4 96/88.2 48/44.1
S/PDIF valid valid valid
ADAT x x valid
S/MUX 2 x valid x
S/MUX 4 valid x x
AES Single valid valid valid
AES Double valid valid x
FIGURE 3
Please see the section of
this manual entitled “About
Digital Audio Formats
and Format Conversion” for a more
detailed explanation of Big Ben’s digital
functionality.
67

APOGEE ELECTRONICS
8
BIG BEN – User’s Guide
APOGEE ELECTRONICS 9
BIG BEN – User’s Guide
Navigating the Front Panel - continued
In VSO mode:
due to the limitations of a
4 digit display, only one
of the three units of measurement
can be displayed accurately; display
values for the remaining two units
are approximated. Whichever unit
of measurement is displayed when
modifying SAMPLE RATE accurately
represents the output; if a second unit of
measurement is selected and SAMPLE
RATE is modied, that second unit of
measurement becomes the accurately
displayed unit. For this reason it’s
recommended to choose the unit of
measurement desired before setting the
SAMPLE RATE value.
When in VSO mode, please
note that the SAMPLE RATE
value is not retained in Non-
Volatile memory, and will be lost when
Big Ben is power cycled. All other
settings are memorized.
To clock most digital systems, a word
clock of the same frequency as the
audio sample rate is required. For
those systems where the required word clock
is a multiple of the sample rate, WC Out 5 & 6
may be set accordingly.
8) PULL UP/DOWN – The Pull Up/Down parameter is active only
when SAMPLE RATE is set to INTernal or VIDEO. The frequency of
the SAMPLE RATE may be modied by 4 dened percentages to ac-
commodate specic situations encountered during video production
and post. The +- 4% values are usually employed when transferring
between PAL video and lm, while the +- 0.1 values are employed
when transferring between NTSC video and lm.
VSO (Variable Speed Override) is the term historically used to
denote the variable speed control on a tape machine. Variable Speed
is accomplished in the digital audio domain by modifying the sample
rate. Big Ben allows this modication of the SAMPLE RATE over
a wide range of values when CLOCK SOURCE is set to INTernal
and the PULL UP/DOWN parameter is set to VSO, Moreover, the
SAMPLE RATE may be displayed in three units of measurement : 1)
absolute frequency in Hz 2) amount of change in percentage, and 3)
amount of change in cents (i.e. subdivisions of a semitone).
For VSO operation,
1) Ensure that CLOCK SOURCE is set to INTernal, and that the
desired base SAMPLE RATE has been selected.
2) Set PULL UP/DOWN to VSO
3) Select the SAMPLE RATE parameter, and set the desired
amount of varispeed with the UP or DOWN buttons (Pressing
and holding the UP or DOWN key causes values to scroll more
rapidly) The SAMPLE RATE value will now vary in increments of
1 hz,, 0.1% (1% when the amount of change is greater than 10
%) or 1 cent, depending on the unit of measurement displayed.
To change the units of measurement displayed, select the SAMPLE
RATE parameter and press and hold either the PREV or NEXT button.
To reset the SAMPLE RATE to an unchanged state, select the SAM-
PLE RATE parameter and press and hold both the UP and DOWN
buttons. Alternatively, it’s possible to toggle the PULL UP/DOWN
parameter between NONE and VSO.
9) WC OUT 5 – This parameter allows the frequency of Word Clock
Output 5 to be set to a multiple of the SAMPLE RATE.
89

APOGEE ELECTRONICS
8
BIG BEN – User’s Guide
APOGEE ELECTRONICS 9
BIG BEN – User’s Guide
10) WC OUT 6 – Similar to the WC OUT 5 parameter, the frequency of
Word Clock Output 6 may be set to a multiple of the SAMPLE RATE.
Valid settings are determined by the SAMPLE RATE
as depicted in FIGURE 4 below
If the UP button is pressed while powering up the unit, WC outputs 5 & 6
transmit clock signals suitable for DSD devices, as depicted in FIGURE 5
below. WC OUT 5 & 6 default to fsx1 and may not be modied
11) WC OUT/TERMINATION – Correct termination of word clock inputs
is crucial to a stable clock conguration. The 6 WC OUT/TERMINATION
LEDs indicate whether each of Big Ben’s six Word Clock outputs have
been properly terminated at the inputs to which they are connected.
Three states of termination are indicated for each word clock output:
• Red LED on – Input is OVER terminated
• Green LED on – Input is correctly terminated
• No LED on – Input is un-terminated or output is not connected
Navigating the Front Panel - continued
Termination sensing can also be
used to verify the integrity of word
clock cables by following these
steps (Big Ben must be locked to perform
this test):
1) Connect one end of the cable
being tested to one of Big Ben’s
word clock outputs, and leave
the other end unconnected - the
corresponding Termination Sensing
LEDs should remain unlit; if the red
LED lights, then the cable’s shield is
shorted to it’s center conductor.
2) Now connect a 75 ohm termination
plug to the unconnected end of the
cable - the corresponding green
Termination Sensing LED should
light; if no LEDs light, then either
the shield or center conductor has
become open. If the red LED lights
again, then either the connector has
shorted or a 50 ohm termination
plug is connected.
192/176.4 96/88.2 48/44.1
fs x 256 x x valid
fs x 4 x x valid
fs x2 x valid valid
fs x1 valid valid valid
fs/2 valid valid x
fs/4 valid x x
WC OUT
5&6 value Big Ben SAMPLE RATE
FIGURE 4
FIGURE 5
192/96/48 kHz 176.4/88.2/44.1kHz
WC OUT 5 (Fs x64 at 44.1/48kHz) 3.072 MHz 2.8224 MHz
WC OUT 6 (Fs x128 at 44.1/48kHz) 6.144 MHz 5.6448 MHz
10 11

APOGEE ELECTRONICS
10
BIG BEN – User’s Guide
APOGEE ELECTRONICS 11
BIG BEN – User’s Guide
Connections on the Rear Panel
1) AES IN 1 & 2 – These XLR connections accept AES/EBU input in the format selected
by the front panel AES parameter. When AES is set to SINGLE, each connection
accepts a discrete stereo input; when AES is set to DOUBLE, both connections used in
conjunction accept one stereo input.
2) AES OUT 1 & 2 - These XLR connections provide AES/EBU output in the format
selected by the front panel AES parameter. When AES is set to SINGLE, stereo output
is duplicated on each connection; when AES is set to DOUBLE, both connections used
in conjunction provide one stereo output.
3) S/PDIF IN/OUT – These RCA (Cinch) connections provide S/PDIF Coaxial Input/
Output
4) OPTICAL IN/OUT – These Toslink connections provide Optical input/output in the
format selected by the front panel OPTICAL parameter. Please see the section entitled
“About Digital Audio Formats and Format Conversion” for detailed information on the
formats provided.
5) OPTION CARD – This slot is reserved for Option cards which provide additional input/
output formats, such as FireWire.
6) VIDEO/WORD CLOCK IN – This BNC connection accepts both TTL Logic and
video black burst signals, according to the front panel CLOCK SOURCE parameter.
When CLOCK SOURCE is set to Video, the video format (PAL, NTSC or B&W) is
automatically detected. The Video/Word Clock input is internally TERMINATED – no
external termination should be used.
7) WC OUT 1-6 – These BNC connections provide TTL logic level word clock outputs.
Outputs 1-4 transmit clocks whose frequency equals the SAMPLE RATE, while Outputs 5
& 6 may be set to transmit a clock whose frequency is a multiple of the SAMPLE RATE.
8) AC IN – This IES connection accepts an AC input of 100 to 240 VAC at a frequency of 50
to 60 Hz.
1 2 3
5
6
7
4
8

APOGEE ELECTRONICS
10
BIG BEN – User’s Guide
APOGEE ELECTRONICS 11
BIG BEN – User’s Guide
About Digital Audio Formats and Format Conversion
As sample rates and bit resolutions have increased, digital audio formats have been
modied to handle the increased ow of data, to the point where the proliferation of
format variations has led to some confusion. For example, 5 variations of the AES/EBU
format have been developed to handle sample rates between 44.1kHz and 192kHz.
FIGURE 6 depicts the characteristics of the digital audio formats available on Big Ben,
including the names by which the format is known, the connector used, valid sample
rates, the number of digital audio channels per connection, and the rate of transmission.
For example, AES Double Wire format can carry only 1 channel of audio per connection,
uses XLR connectors, is used only with sample rates between 88.2 and 192 kHz, and
transmits data at half the sample rate – i.e., bits travel at 48kHz when transmitting a
96kHz digital audio signal.
To convert a digital audio signal from one format to any other format, the source format
must be selected as the CLOCK SOURCE. Digital audio data present at the selected
input will be routed to all outputs capable of transmitting digital audio data.
When format converting, Big Ben will transmit as many channels as possible based on
the input format selected and the capability of each output format. For example, if S/MUX
2 input (capable of accepting 4 channels) is selected as the CLOCK SOURCE and AES
is set to SINGLE (thus allowing transmission of 2 channels on each connector), S/MUX
input channels 1 & 2 will be routed to AES Output 1, while S/MUX input channels 3 & 4
will be routed to AES Output 2; on the other hand, only S/MUX channels 1 & 2 will be
routed to the S/PDIF Coaxial output (capable of transmitting 2 channels on the sole
S/PDIF connector).
About SureLock
Thanks to SureLock, Apogee’s intelligent clock continuity algorithm, even the loss of the
input reference will not degrade the stability of Big Ben’s outputs. When the selected
CLOCK SOURCE is no longer applied to Big Ben, the unit will continue to generate
clock outputs at the last known valid frequency; the “Wide” arrow will blink to indicate the
loss of the input reference while the blue “Narrow LED will light solidly to indicate stable
output. When an input reference is re-connected, Big Ben will attempt to regain lock as
seamlessly as possible; nonetheless, it’s recommended to re-connect the input reference
at a moment when a brief interruption of Big Ben’s output won’t pose a problem.
Name(s) Connector used Valid Sample Rates Channels per
connector Digital Data Rate
AES Single Wire or Double Fast or
Single Wide XLR 44.1-192kHz 2 Fs x 1
AES Double Wire or Double Wide XLR 88.2-192 kHz 1 Fs /2
S/PDIF Coaxial RCA (coaxial) 44.1-192kHz 2 Fs x 1
S/PDIF Optical Toslink (optical) 44.1-96kHz 2 Fs x 1
ADAT Toslink (optical) 44.1-48kHz 8 Fs x 1
S/MUX 2 Toslink (optical) 88.2-96kHz 4 Fs /2
S/MUX 4 Toslink (optical) 176.4-192kHz 2 Fs /4
FIGURE 6

APOGEE ELECTRONICS
12
BIG BEN – User’s Guide
APOGEE ELECTRONICS 13
BIG BEN – User’s Guide
Internal Adjustments
We’ve gone to great lengths to avoid DIP switches and other inaccessible controls on Big Ben, but
there are a few internal jumpers used to congure infrequently modied parameters. See the photo
below for an indication of each jumper’s location.
Power On Mode –Jumper P8
1) Jumper P8 set to MANUAL – when AC power is applied to the input, Big Ben does not power
up immediately; to power on the unit, the POWER button must be pressed. This is the default
setting.
2) Jumper P8 set to AUTO – when AC power is applied to the input, Big Ben powers on
immediately; nevertheless, the POWER switch is functional. This setting may be preferred
when a Master switch controls several devices including Big Ben.
Power Switch Disabled – Jumper P27
When a jumper is removed from P8 and installed across P27, the power switch is disabled,
and has no function. As is the case with all electronics, keeping Big Ben powered on at all
times ensures the most stable operation. Power Switch Disabled ensures that the unit is not
accidentally powered off.
SureLock Defeat –Jumper 17
When a jumper is installed across P17 and Big Ben is power cycled, SureLock functionality is
defeated. For those who get nervous when machines silently take over.
Defeat FC (Format Conversion) – Jumper 18
When a jumper is installed across P18 and Big Ben is power cycled, Format Conversion
functionality is defeated and Digital “Black” is sent to all digital audio outputs.
FIGURE 7
P8
P27
P17
P18