Graham-Patten SoundPals ADC-24 User manual

SoundPals™
ADC-24 User Guide
Stereo A-to-D Converter

Graham-Patten is a division of
Printing History
SoundPals™ADC-24 A-to-D converter
Rev. N/C
March 2007
Printed in U.S.A.
Part Number 08-2045-00
The information contained in this guide is subject to change without notice or obligation.
Copyrights and Trademarks
© 2005 GRAHAM-PATTEN SYSTEMS, INC.
Contents of this publication may not be reproduced in any form without the written permission of Graham-Patten.
Reproduction or reverse engineering of copyrighted software is prohibited.
FCC Compliance
This equipment has been tested and found to comply with the limits for a Class A digital device pursuant to Part 15
of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the
equipment is 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 instruction 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 correct the interference at your own expense.
Warranty Statement
Graham-Patten warrants that the equipment it manufactures is free from defects in workmanship and materials and
meets applicable published specifications. Equipment that has been operated within published ratings and has not
been subjected to abuse or modification, and which fails because of such defects, will be replaced or repaired at the
Company’s discretion if it is returned, freight prepaid, to Graham-Patten within seven years of receipt.
This warranty supersedes all other Warranties, express or implied. Graham-Patten is not liable for any
consequential damages.
Company Address
GRAHAM-PATTEN SYSTEMS, INC.
119 East McKnight Way, Unit A
Grass Valley, California 95949
Telephone: [phone]
Fax: [phone]
e-mail: [email protected]
World Wide Web: www.gpsys.com

Table of Contents
ii • Table of Contents ADC-24 User Guide
Table of Contents ii
Introduction 1
What are SoundPals?.............................................................................................................. 1
Documentation Conventions.................................................................................................... 1
Signals and Values .................................................................................................................. 1
Warnings.................................................................................................................................. 1
Unpacking and Inspection ....................................................................................................... 2
Power Supply Note .................................................................................................................. 2
ADC-24 3
About the ADC-24.................................................................................................................... 3
ADC-24 Installation.................................................................................................................. 5
Connecting Power ............................................................................................................. 5
Connecting Inputs ............................................................................................................. 5
Connecting AES Reference ..............................................................................................5
Connecting Outputs........................................................................................................... 5
ADC-24 Operation ................................................................................................................... 6
ADC-24 Interconnection ..........................................................................................................7
Basic - Inserting Analog Equipment .................................................................................. 7
Basic - Analog Input to Digital Mixer ................................................................................. 7
Advanced - Multiple Analog Inputs to Digital Mixer........................................................... 8
ADC-24 Internal Jumpers ........................................................................................................ 9
ADC-24 Troubleshooting ....................................................................................................... 11
ADC-24 Specifications...........................................................................................................12
Audio Specifications ........................................................................................................ 12
Environmental Specifications and Dimensions ............................................................... 12
Inside the Module ........................................................................................... 13
In This Section ....................................................................................................................... 13
Before You Begin................................................................................................................... 13
Opening the Module ..............................................................................................................13
Closing the Module ................................................................................................................ 13
External Power ................................................................................................ 14
About Power Supplies ...........................................................................................................14
CE Compliance...................................................................................................................... 14
Portable Power Sources ........................................................................................................ 14
Power Supply Specifications ................................................................................................. 14
Power Supply Sources .......................................................................................................... 15

Introduction
ADC-24 User Guide Page 1
What are SoundPals?
Each Graham-Patten SoundPals module is essentially a digital audio building block that can be
used independently, or interconnected to perform more advanced mixing and audio processing
functions.
SoundPals can be used in both standalone and system configurations:
•In a “standalone” configuration, each SoundPals module is designed to perform a specific
audio processing function such as ADAT-to-Analog conversion. In this way, each module
functions as a perfect low-cost adjunct to larger mixing consoles (such as the Graham-
Patten D/ESAM series) — for single-purpose processing tasks.
•In a “system” configuration, SoundPals can be linked to form more comprehensive digital
audio tools. For field recording, studio applications, and workstation applications,
SoundPals can be used to seamlessly perform functions that would otherwise require
extensive peripheral gear. Best of all, SoundPals “systems” can be re-configured quickly
and easily — to suit your changing audio production requirements.
All SoundPals modules are extremely compact, rugged, and identical in size for ease of
installation, interconnection, and use. In addition, SoundPals support AES3id. This allows
longer, more robust AES signal distribution using standard coaxial cable. Error free distances of
1000 feet can be attained using inexpensive coaxial cables.
Documentation Conventions
The following documentation conventions are used in this guide:
•Buttons, knobs, connectors, and switches are indicated in bold-faced capital letters. For
example:
Adjust the left GAIN TRIM to …
•Primary sections are listed in bold text, with a line above:
Primary Section
•Secondary sections are listed in bold text, with no line:
Secondary Section
Signals and Values
Note the following important information regarding audio signal level:
•0 dBu = 0.778Vrms
•AES3 = Balanced output with 2 channels of digital audio (left and right)
•AES3id = Unbalanced output with 2 channels of digital audio (left and right)
Warnings
Please observe the following important warnings:
•Heed all warnings on the unit and in the instructions.
•Do not use this product in or near water.
•Route power cords and other cables so that they are not likely to be damaged.
Disconnect power before cleaning. Do not use liquid or aerosol cleaners; use only a
damp cloth.

ADC-24 User Guide
Page 2
Unpacking and Inspection
When you receive your SoundPals modules, inspect the cartons for signs of damage. Contact
your dealer and the shipper immediately if you suspect any damage has occurred during
shipping. Check the contents of each box to be sure that all parts are included. If any items are
missing, contact your dealer immediately.
Power Supply Note
SoundPals are delivered with a power connector only. A separate power supply must be
obtained. Graham-Patten offers several power solutions for both domestic and international
customers. Refer to “External Power” for detailed power specifications for users who wish to
configure their own power source, rather than purchase one from Graham-Patten.

ADC-24
ADC-24 User Guide Page 3
About the ADC-24
The SoundPals ADC-24 is a stereo 24-bit, analog-to-digital AES converter. The unit takes two
line-level analog inputs (on XLR connectors), and converts them to one digital AES output
(provided on both XLR and BNC connectors simultaneously).
The ADC-24 offers the following features:
•24-bit A/D converter
•Adjustable level for each input
(-10 to +4 dBu at -20 dBFS)
•AES reference input
•Significant status bits selectable with internal dipswitch
•Active balanced and unbalanced outputs
•LED level indicators for normal and overload conditions
•Optional rack mounting tray (1 RU)
•Compact size, rugged construction
Two versions of the ADC-24 are available:
•44.1 kHz Model
This model defaults to 44.1 kHz, via the internal crystal. However, if an external
reference is applied to the AES REF connector, the output frequency will lock to the
reference.
•48 kHz Model
This model defaults to 48 kHz, via the internal crystal. However, if an external reference
is applied to the AES REF connector, the output frequency will lock to the reference.
NOTE The printed legend on the rear panel indicates the default frequency.
The figure below illustrates the ADC-24’s front panel:
ADC-24 ADC-24
AES OUT
+6V
-60
-20
-3
0
LR
LEVEL
EXT
REF
65
3 4 71
LR
2
GAIN
1) Left Analog Input Gain Trim — L GAIN sets the left channel’s analog input level (the
level that you want to correspond to -20dB below digital clipping).
2) Right Analog Input Gain Trim — R GAIN sets the right channel’s analog input level (the
level that you want to correspond to -20dB below digital clipping).
3) AES Unbalanced Output — provides AES unbalanced output (BNC). Output is
concurrent with the rear panel’s AES balanced output (XLR) — both can be used
simultaneously.

ADC-24 User Guide
Page 4
4) AES Reference LED — the EXT REF LED lights when the sampling frequency is locked
to the externally supplied AES reference signal. The LED is an indication only, not an
alarm.
5) Level Indicator LEDs — provides level indication for each input (calibrated in dB).
When properly adjusted, the following levels are indicated:
•-60 dB: signal present
•-20 dB: normal digital reference level
•-3 dB: approaching clipping
•0dB: A/D converter is clipping
6) Power Connector — accepts the power jack from the 6VDC power supply. Refer to
“External Power” for more information regarding external power.
7) Power LED — the large green LED below the power jack lights when power is applied.
The figure below illustrates the ADC-24’s rear panel:
AES OUT AES REF RIGHT IN LEFT IN
44.1 KHZ
MADE IN THE USA
2 3 4 51
1) ADC Version — the printed legend indicates the default frequency (either 44.1 kHz or 48
kHz).
2) AES Balanced Output — provides AES balanced output via XLR connector. Output is
concurrent with the front panel’s AES unbalanced output (BNC) — both can be used
simultaneously.
3) AES Reference Input — the AES REF connector accepts an AES reference signal
(between 30 kHz and 50 kHz sampling rate). Only timing information is used; audio
content (if any) is ignored. Refer to the “Connecting AES Reference” section for
information on switching frequencies via the reference signal.
4) Right Analog Input — accepts right channel line level analog input. The input level is
adjustable via R GAIN on the front panel of the ADC.
5) Left Analog Input — accepts left channel line level analog input. The input level is
adjustable via L GAIN on the front panel of the ADC.

ADC-24 User Guide Page 5
ADC-24 Installation
This section provides instructions for connecting power, analog inputs, AES reference, and digital
outputs.
Connecting Power
Plug a 6 VDC power supply into the appropriate voltage outlet for your specific country, and
connect the end of the cord into the ADC-24 jack marked +6V. Secure the locking ring finger
tight. The green LED below the jack lights when power is applied.
Connecting Inputs
Connect left and right channel analog inputs to the two rear connectors marked LEFT IN and
RIGHT IN. Balanced sources are connected to pins 2 (+) and 3 (-) with pin 1 and the shell
grounded. Unbalanced sources are connected to pin 2 with pins 1, 3 and the shell grounded.
Refer to the “ADC-24 Operation” section for instructions on correctly adjusting input level.
Connecting AES Reference
The ADC-24 can be synchronized to an alternate output frequency (from the default frequency)
by connecting a valid AES reference signal to the AES REF BNC connector. The EXT REF LED
on the front panel lights when a valid reference signal is applied.
To phase lock the unit’s sample frequency to a reference, connect a reference signal (between 30
kHz and 50 kHz sampling rate) to the AES REF BNC connector. The AES signal output will now
phase-lock to the incoming reference — independent of the ADC’s default reference frequency.
Note that the AES REF input is normally terminated internally with 75
Ω. When it is necessary to
loop reference to several SoundPals, the signal must be terminated only once, and always at the
last unit in the chain. Refer to the “ADC-24 Internal Jumpers” section for information on
changing the input from terminating to bridging.
Connecting Outputs
Connect the digital audio output from one of the AES OUT connectors on the front or rear panel,
and route it to the input of the desired destination device. Both AES3 and AES3id outputs may
be used simultaneously.

ADC-24 User Guide
Page 6
ADC-24 Operation
This section provides instructions for aligning the ADC’s inputs with the gain controls.
Using the Gain Controls
For setting the left and right channel analog input levels, each input has its own level adjustment
on the front panel. Inputs are factory-set for +4 dBu at -20dBFS. Use the following alignment
procedure to set other levels:
To align the left and right analog outputs:
1. Connect a reference analog tone generator to the ADC-24’s LEFT IN and RIGHT IN
connectors.
2. Turn on the reference tone generator, and adjust it to the level that you want to
correspond to -20 dB below digital clipping.
3. While watching the ADC’s front panel Level Indicator LEDs, adjust the ADC’s Land R
GAIN trimmers — until the -20 dB LED just comes on.
This setting provides 20dB of headroom, based on the selected analog input reference level.
Setting the Sample Frequency
Refer to the “Connecting AES Reference” section for instructions on changing the ADC’s
sample frequency.

ADC-24 User Guide Page 7
ADC-24 Interconnection
This section provides basic and advanced interconnection diagrams.
•Basic — Inserting Analog Equipment
In this application, an analog ATR is seamlessly inserted in a digital stream, using both
the DAC and ADC together.
SoundPals DAC-24
AES
Output
SoundPals ADC-24
AES
Input AES Out
AES Ref
Right In
Left In
PWR
R Trim
L Trim
AES Out
AES In
AES In
Right Out
Left Out
PWR
Headphones
Volume
R Trim
L Trim
•Basic — Analog Input to Digital Mixer
In this application, connect analog inputs (e.g., from an ATR) to the ADC — and the
ADC’s AES output to the input of a digital mixer. Note how one of the mixer’s outputs is
used to synchronize the ADC (using the AES REF connector).
SoundPals ADC-24
Analog In
D/ESAM
Mixer
Digital Sources
Digital In
Program Out
AES Out
AES Ref
Right In
Left In
PWR
R Trim
L Trim
AES Out

ADC-24 User Guide
Page 8
•Advanced — Multiple Analog Inputs to Digital Mixer
In this application, ADC and DMIC SoundPals are combined to provide multiple analog
inputs to a digital mixer.
~ An analog ATR feeds an ADC, and then to the mixer via AES.
~ Dual mics are converted to digital in the DMIC, and then to the mixer via AES.
~ An additional analog signal feeds an ADC, and then to the mixer via AES.
~ One of the mixer’s outputs is used to synchronize all SoundPals (via bridging
AES connections).
SoundPals ADC-24
Analog In
D/ESAM
Mixer
Digital Sources
SoundPals ADC-24
Analog ATR
Analog
Microphones
Bridge
Bridge
Term
Program Out Digital In
AES Out
AES Ref
Right In
Left In
PWR
R Trim
L Trim
AES Out
SoundPals DMIC-24
AES Out
AES Ref
Right In
Left In
PWR
Sensitivity
AES Out
AES Out
AES Ref
Right In
Left In
PWR
R Trim
L Trim
AES Out

ADC-24 User Guide Page 9
ADC-24 Internal Jumpers
This section provides information about the ADC-24’s internal jumpers and adjustments.
NOTE For detailed instructions on opening and closing
the ADC-24, see Appendix A, “Inside the
Module.”
The figure below shows the ADC-24’s internal jumper locations:
04-0222-
ADC-24
GRAHAM-PATTEN SYSTEMS
Made in U.S.A.
GRASS VALLEY, CALIFORNIA
04-0246-
87654321
J5
OPEN
J4
Input
Termination
Jumper
High Pass
Filter Jumper
Status Bit
Dip Switch
Jumper Pinout 123
J9
•J4 is the High Pass Filter jumper. With pins 1 and 2 connected, the filter is disabled. With
pins 2 and 3 connected, (factory default) the filter is enabled.
•To change the AES reference input from terminating to bridging, remove jumper J5.
SW1 is the Status Bit Dip Switch that is used to set the channel status on the AES outputs. The
switch is an eight-position DIP, all of which are active. Switch shows default factory switch
settings.
OPEN
1 top position
0 bottom position
12345678
For all switches:
~ 0 is open
~ 1 is closed

ADC-24 User Guide
Page 10
•If Switches 1 and 2 are Closed, (factory default) the unit is in the Professional Mode
and the following switch settings apply.
•Switch 3defines the Audio Mode.
Function SW3
Audio 0
Non-Audio 1
•Switches 4and 5define the Sample Frequency.
Function SW4 SW5
Not Indicated 0 0
48 kHz 1 0
44.1 kHz 0 1
32 kHz 1 1
•Switches 6and 7define the Emphasis.
Function SW6 SW7
Not Indicated 0 0
None 1 0
50/51 0 1
CCITT J.17 1 1
•Switch 8 determines the Channel Mode.
Function SW8
Not Indicated 0
Stereo 1
•Switch 5defines the Copy Mode.
Function SW5
Inhibited 0
Permitted 1

ADC-24 User Guide Page 11
•Switch 6and 7defines the Category Code.
Function SW6 SW7
General 0 0
Digital Converter 1 0
Laser, CD 0 1
Magnetic Tape 1 1
•Switch 8 determines the Generation Table.
Function SW8
1st Generation or Higher 0
Original 1
ADC-24 Troubleshooting
The table below lists several ADC-24 problems, and provides a variety of “checklist” procedures
designed to solve them.
Problem Procedure
No signal at either
AES output.
•Is power applied? Check power LED and power supply.
No audio on AES
output. •Is input connected correctly? Check +to pin 2, or ground to pin 3.
Front panel meters
not registering.
•Adjust input levels.
Ext Ref indicator not
lit on front panel.
•Is AES reference connected? Check that an AES signal is applied to
the reference input if you want synchronized sampling.
•Is the reference input a valid AES signal?
•Is the reference input sampling frequency between 30 KHz and 50
KHz?
NOTE Please contact the GPS factory if the problem still exists after completing the
above procedures.

ADC-24 User Guide
Page 12
ADC-24 Specifications
This section provides audio and environmental specifications.
Audio Specifications
Parameter Specification
Analog Inputs
Impedance >15 kΩ
Gain range -10dBu to 6 dBu for -20dBFS output
Frequency Response +0/-0.1dB, 20 Hz – 20 KHz
THD+N @ -20dBFS -91 dB, 20Hz-20 KHz
THD+N @ -1dBFS -84 dB, 20Hz-20 KHz
Dynamic range 96 dB
CMRR >60dB, 20 Hz – 10 KHz
Crosstalk <−84dB, 20 Hz – 20 KHz
Digital Outputs
Terminated 110
ΩAES3, 75ΩAES3id
Sample Rate 30 KHz – 50 KHz
Output resolution 24 Bit
Options
RT-2, 1RU rack tray for mounting up to 3 units
Power supplies:
•PSU-1, 90-260V 50/60Hz in-line power supply with detachable IEC power cord
NOTE •All specifications listed above subject to change without notice.
•All parameters listed above specified at 48 kHz sampling frequency.
Environmental Specifications and Dimensions
Parameter Specification
Dimensions
(less connectors)
5.2W x 1.62H x 6.625D
13.2 x 4.1 x 16.8 cm
Power 300 mA @ 6Vdc
Operating Temp. 10 – 50
°C
Operating Humidity 10 – 90% RH non-condensing

ADC-24 User Guide Page 13
Inside the Module
In This Section
This section provides instructions for opening and closing the SoundPals ADC-24 module to gain
access to the internal circuit board.
NOTE The internal circuit board should only be removed from the module if you want to set
the termination jumper, the High Pass Filter jumper or the Status Bit dip switch.
Before You Begin
Check the following items before opening the module and attempting to remove the internal
circuit board:
 If required, remove the SoundPals module from the rack tray.
 Disconnect the power supply from the front of the product.
 Disconnect all input and output cables.
 Perform the remaining steps only in a static free environment. Make sure that you and
the product are both grounded.
The following tools are required:
•#2 Philips screwdriver
Opening the Module
Use the following steps to open the ADC-24 SoundPals module:
1. On the rear panel, remove the four Phillips screws from the four corners of the module.
2. On the rear panel, remove all Philips XLR mounting screws from the module.
3. On the rear panel remove the BNC nut and associated lock washer.
4. Remove the rear panel.
5. On the front panel, remove four Phillips screws from the four corners of the module.
6. Pulling the front panel, carefully draw the internal circuit board and front panel assembly
from the housing.
CAUTION Keep the case horizontal so that the BNC bushing stays with the connectors.
7. Set the housing and all mounting hardware in a safe place.
Closing the Module
Use the following steps to close the ADC-24 SoundPals module:
1. Ensure that product label is on the bottom.
2. Carefully slide the internal circuit board and front panel assembly through the housing.
Keep the case horizontal so that the BNC bushing stays with the connectors.
3. Replace, but do not tighten, the four Phillips screws in the front corners of the SoundPals
module.
4. Replace the rear panel.
5. Replace, but do not tighten, the four Phillips screws in the rear corners of the SoundPals
module.

ADC-24 User Guide
Page 14
6. Tighten the four front plate corner screws making sure that the plate is aligned with the
housing. Repeat with the four rear plate corner screws.
7. Replace all Philips XLR mounting screws at the rear of the SoundPals module.
8. Replace the BNC nut and associated lock washer at the rear of the SoundPals module.
CAUTION Do not over tighten the screws.
External Power
About Power Supplies
An external power supply conforming to the specifications listed in the following “Power Supply
Specifications” section must be used to guarantee that published SoundPals performance
figures are met. Any power supply meeting these specifications will supply adequate power for a
single SoundPals module. Although the specification is written for power supplies running from
AC line inputs, DC (battery) sources may be used if they meet all of the listed requirements.
CE Compliance
For CE compliance, the power supply that you use must comply with the following requirements:
•Low Voltage Directive 73/23/EEC
•EMC Directive 89/336/EEC
•EMC Directive 93/68/EEC
•The connector locking ring must be tight.
Portable Power Sources
For portable SoundPals power sources, sealed lead-acid, nickel cadmium or alkaline primary
batteries may be used. However, the maximum voltage must not exceed 8.6 volts, and a
minimum of 5.6 volts is required for normal operation. Maximum current drain will be 325mA.
Power Supply Specifications
The following specifications must be met over all anticipated operating conditions including AC
power line range, temperature range, etc.
Parameter Specification
Output voltage 5.6V minimum (measured at trough of ripple) at 321mA constant current.
8.6V maximum (measured at peak of ripple) at 210 mA constant current.
Ripple voltage 2V p-p at 700 mA constant current.
400mV p-p at 700 mA constant current with external 2200
µF capacitor.
Connector Switchcraft 761K with center positive, sleeve negative.