ATI DDA208-BNC User Manual

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DDA-208

SERIES 2

HIGH RESOLUTION DUAL 1x4

DIGITAL AUDIO DISTRIBUTION

AMPLIFIERS

OPERATING AND MAINTENANCE MANUAL

© Copyright 2013, ATI Audio

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DESCRIPTION

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DDA208 Series 2 1x4 Dual Digital Audio Distribution Amplifiers are designed to
regenerate, isolate and distribute digital audio data formatted in accordance with
specifications AES3-1992 and IEC 958. This is commonly called AES/EBU
formatting or AES3.

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DDA208 Series 2 units inputs feed AES audio to eight separate outputs. Internal
jumpers select either re-clocking or non-reclocking of the input signal. In most
cases, re- clocking is preferred, as this feature improves the integrity of weak or
distorted input signals. Re-clocking may be switched off to allow distribution of
AES sync signals, Dolby E encoded AES signals, or other signals that should
not be re- clocked.

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DDA208 Series 2 units work with AES signals that contain sample rates from 27
through 192kHz and16-bit through 24-bit density, thus permitting very high
resolution signals to be distributed.

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The Model DDA208-XLR uses XLR connectors and operates from and drives a
110-ohm balanced shielded twisted pair distribution system per AES3-1992.

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The Model DDA208-BNC uses BNC connectors and operates from and drives
single-ended 75-ohm coaxial cable per AES-3id-1995 and is designed
to integrate easily into video facilities.

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S/PDIF (consumer) formatted digital audio data differs primarily in the use of
consumer type "RCA" audio connectors in an unbalanced 75 ohm system and
can be handled by a DDA208-BNC with use of an RCA-to-BNC input cable.

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Input Loop-through connection is provided to permit multiple units to be stacked,
or to insert the DDA208 into your digital workflow. Switchable line termination is
provided via Internal jumpers. Standard practice dictates that the last AES input
be terminated; therefore, if you are not using the loop-through feature, Input
Termination should be switched ON.

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FEATURES

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• Accepts sample rates from 27 to 192kHz

• Switchable re-clocking regenerates stable data before distribution

• Loop thru transformer balanced and isolated inputs

• Switchable input termination

• Individual, transformer balanced and isolated 110-ohm XLR outputs (XLR only)

• Individual isolated 75-ohm BNC outputs (BNC only)

• Eight outputs

• Quiet, internal power supply

• AC Input 100-250 VAC 50/60 Hz, 25W Maximum

• Attractive and rugged 1RU package

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DESCRIPTION

INPUTS

Incoming AES/EBU formatted digital audio data is selected by the internal
jumpers and applied to the input transformer. Both XLR and BNC inputs are
balanced and DC isolated from ground. Input termination resistors at
75 ohms for BNC inputs or 110 ohms for XLR inputs can be switched in or out of
the circuit with the internal jumpers. Inputs should always be terminated unless
they are looped thru to another device or DDA input. The last device or input
should always terminate the line.

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RECEIVERS

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When input re-clocking is enabled, the equalized AES/EBU data stream is
applied to the receiver circuit, which recovers the clock and synchronization
signals and separates the audio and digital data. The audio data may be 16 to 24
bits at sample rates from 27 to 192 kHz.

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Frame sync (FSYNC), Serial Clock (SCK), Serial audio data (SDATA), Channel
status (C), User channel data (U), and data validity information (VERF) are
passed directly to the transmitter section for reformatting into the output data
stream. VERF is an OR’ing of the validity information from the incoming data (V)
with an internal error flag (ERF) that detects serious transmission errors such as
parity errors, bi-phase coding violations and an out-of-lock PLL receiver. VERF
then becomes the transmitted validity bit (V) and can be used by downstream
error correction devices to interpolate through errors.

TRANSMITTERS

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The Frame sync (FSYNC), Serial Clock (SCK), Serial audio data (SDATA), Channel
status (C), User channel data (U), and data Validity information (VERF) are passed
directly to the transmitters for reformatting into the AES/EBU output data stream. The
transmitters are capable of operation from 27 to 192 kHz equivalent sample rates. The
transmitters operate in a transparent mode, which allows the transmitter block
structure (Channel Status, User and Validity bits) to be slaved to the block structure of
the receiver. In the transparent mode the propagation delay of data are less than 25
nanoseconds even at the lowest sample rate.

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OUTPUT DRIVERS

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DDA208-XLR units are equipped with balanced, 110-ohm, transformer coupled
outputs and XLR type connectors. DDA208-BNC units use the alternative 75­ohm unbalanced outputs to BNC coax connectors. The XLR outputs are in full
compliance with specification AES3-1992 and the BNC outputs are in
accordance with the recommendations of AES-3id-1995. XLR outputs are
transformer coupled for ground isolation.

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POWER SUPPLY

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Power transformer primary windings are paralleled for 115VAC or wired in series
for 230VAC. Internal jumpers allow field modification if necessary. See below for
voltage conversion instructions.

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INSTALLATION

LOCATION

To avoid addition of jitter (timing variations) to the digital bitstream, which could
cause noise and distortion in the recovered audio, avoid locating the DDA in
close proximity to a high energy, high frequency switching type power supply or a
power amplifier that utilizes a switching supply. If possible, do not power both
devices from the same AC power line.

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Expensive components start to die at internal temperatures above 70°C (158°F).
We recommend that you maintain rack temperatures below 50°C (122°F) to
prevent excessive internal temperature buildup. This is another good reason not
to mount the DDA directly above that 500W power amplifier.

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POWER

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If it is necessary to convert a unit wired for 115VAC to 230VAC operation, unplug
the unit from the power source, remove the cover mounting screws and locate
the jumpers next to the power transformer. Clip the jumpers 1-2 and 3-4 (don’t
unsolder), jumper from 2-3 carefully soldering together the free ends of 2-3
previously clipped. This procedure is recommended to avoid soldering damage to
the multi-layer PC board.

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WIRING

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XLR types require special controlled impedance, 110 ohm, low loss, foil shielded,
twisted pair cables. Standard audio cable is not recommended except for runs of
only a few feet. Belden and most other cable manufacturers offer special digital
audio cabling for this application. With equalization, cable runs of 300 meters
(about 1000 feet) should be achievable. BNC types use 75-ohm coax (RG59).
Select a cable for losses less than 20dB at 12MHz (for data rates up to 96kHz) at
the maximum distance you require. Runs up to 1000 meters should be readily
achievable with low loss coax.

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SPECIFICATIONS

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INPUTS

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Connectors: 2 XLR female or BNC, DC isolated from chassis.

Input connector pairs paralleled for loop-thru.

Level: 200mVp-p minimum

Impedance: Transformer isolated, balanced and floating, XLR inputs 110

ohms, and BNC inputs 75 ohms

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Termination: Terminating resistors may be switched in or out from

Internal jumpers

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Sample Rates: Accepts 27kHz to >192kHz

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Clock: With re-clocking on, regenerated from input signal; clock

jitter <300 picoseconds peak-to-peak at 96kHz sample rate

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With re-clocking off, input clock is passed directly to outputs

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OUTPUTS

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Connectors: 8 x XLR male or 8 x BNC chassis mount

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Levels: XLR, 4Vp-p loaded at 110 ohms

BNC, 2Vp-p loaded at 75 ohms

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Impedances: XLR: 110 ohms, balanced, transformer isolated

BNC: 75 ohms, unbalanced

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Output Jitter: <300 picoseconds peak to peak at 96kHz sample rate

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Propagation Delay: <25 nanoseconds

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POWER Internal supply, 115/230VAC+/-10%, 50/60Hz, 10VA,

IEC320 3 pin connector

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SIZE 1 RU, 19”(48.3cm) W X 1.75”(4.5cm) H X 8.5”(21.6cm) D

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WEIGHT 7 lbs. (3.2kg) net; 9 lbs. (4.1kg) shipping weight

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MODELS: DDA208-XLR

DDA208-BNC

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One Year Limited Warranty

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ATI warrants this product to be free from defects in materials and workmanship to its original
owner for a period of one year from date of purchase. ATI will repair or replace such product or
part thereof, which upon inspection by ATI, is found to be defective in materials or workmanship.

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The Proper Return Authorization Number must be obtained from ATI in advance of return.
Contact ATI at 856-626-3480 or email [e-mail] to receive the number
and instructions for return of your unit.

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A written statement providing the name, address, daytime telephone number and email address
of the original owner, together with receipt from the original purchase, and a brief description of
any claimed defects, must accompany all returns. Parts or product for which replacement is made
shall become the property of ATI.

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The customer shall be responsible for costs of transportation and insurance to the factory of ATI,
and shall be required to prepay such costs.

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ATI shall use reasonable efforts to repair or replace any product covered by this limited warranty
within thirty days of receipt. In the event repair or replacement shall require more than thirty days,
ATI shall notify the customer accordingly. ATI reserves the right to replace any product that has
been discontinued from its product line with a new product of comparable value and function.

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This warranty shall be void in the event a covered product has been damaged, or failure is
caused by or attributable to acts of God, abuse, accident, misuse, improper or abnormal usage,
failure to follow instructions, improper installation or maintenance, alteration, or lightning, power
fluctuations and other incidental or environmental conditions. Further, product malfunction or
deterioration due to normal wear is not covered by this warranty.

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ATI DISCLAIMS ANY W ARRANTIES, EXPRESS OR IMPLIED, WHETHER OF
MERCHANTABILITY OF FITNESS FOR A PARTICULAR USE, EXCEPT AS EXPRESSLY SET
FORTH HEREIN. THE SOLE OBLIGATION OF ATI UNDER THIS LIMITED WARRANTY SHALL
BE TO REPAIR OR REPLACE THE COVERED PRODUCT, IN ACCORDANCE WITH THE
TERMS SET FORTH HEREIN. ATI EXPRESSLY DISCLAIMS ANY LOST PROFITS, GENERAL,
AND SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES WHICH MAY
RESULT FROM BREACH OF ANY WARRANTY, OR ARISING OUT OF THE USE OR
INABILITY TO USE ANY ATI PRODUCT.

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Some states do not allow the exclusion or limitation of incidental or consequential damages or
limitation on how long an implied warranty lasts, so the above limitations and exclusions may not
apply to you.

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This warranty gives you specific legal rights, and you may also have other rights that vary from
state to state.

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ATI reserves the right to modify or discontinue, without prior notice to you, any model or style
product.

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If warranty problems arise, or if you need assistance in using your product contact us.

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