ATI DDA212-BNC User Manual

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© Copyright 2011, ATI Audio Inc.

DDA-212 SERIES 2

Models DDA-212BNC and DDA-212XLR

192kHz AES/EBU DIGITAL AUDIO

DISTRIBUTION AMPLIFIERS

OPERATING AND MAINTENANCE MANUAL

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DESCRIPTION
DDA-212 Series 2 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.

DDA-212 Series 2 units have two inputs and 12 outputs, with the assignment of
inputs and outputs configurable from a front panel switch. The unit may be
operated as a Dual 1X6 or as a 2-Input 1X12, depending on the Input Select
switch setting. The selected input feeds AES audio to either six or all 12 separate
outputs.

A front panel switch selects 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.

DDA-212 Series 2 units work with AES signals that contain sample rates from 27
through 192kHz and 16-bit through 24-bit density, thus permitting very high
resolution signals to be distributed.

The front panel displays full status of the input signal, including Sample rate,
Word Length, Digital Errors and Pro or Consumer Mode.

DDA-212 Series 2 units contain a unique automatic equalization function that can
adjust for extremely long input lines. Equalization works independently for each
input. A Front Panel Lock feature protects all your settings.

The Model DDA-212XLR uses XLR connectors and operates from and drives a
110-ohm balanced shielded twisted pair distribution system per AES3-1992.

The Model DDA-212BNC 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.

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 DDA-212BNC with use of an RCA-to-BNC input cable.

Input Loop-through connections for each of the two inputs are provided to permit
multiple units to be stacked, or to insert the DDA-212 into your digital workflow.
Switchable line termination is provided. 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

• Configurable for Dual 1X6 or 2-Input 1X12 operation

• Accepts sample rates from 27 to 192kHz

• Displays standard sample rates of 32, 44.1, 48, 88.2, 96, 176.4 and 192 kHz

• Displays Word Length of 16, 18, 20 and 24 bit

• Status and error LEDs show clock lock and data validity

• Automatic input equalizers compensate for very long cable runs

• 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)

• Two front-panel-selectable inputs

• 12 outputs

• Front panel control locking system

• Quiet, internal linear power supply

• Attractive and rugged 1RU package

DESCRIPTION
INPUTS

Incoming AES/EBU formatted digital audio data from Inputs 1 and 2 is applied to
individual input transformers. 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
front panel Input Term switch. 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.

INPUT EQUALIZERS

The input signals feed automatic cable equalizer circuits. Input equalization
should only be necessary for extremely long input cable lengths and should only
be used if proven to be necessary. Automatic equalization is enabled by pressing
the front panel button labeled Input EQ. The automatic equalizer provides only
the minimum amount of boost required to compensate for excess cable roll-off to
avoid over-equalization, which can degrade noise margins. Input equalizers work
independently for Input 1 and Input 2.

RECEIVERS
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. Errors
are displayed on the front panel to aid in troubleshooting. VERF then becomes
the transmitted validity bit (V) and can be used by downstream error correction
devices to interpolate through errors.

FRONT PANEL DISPLAYS AND SWITCHES
Power

Indicates that low voltage DC is applied to the input of the voltage regulators.
Input Fault

Illuminates when a digital error is present. Inputs 1 and 2 are simultaneously and
separately monitored.

Input Termination
Indicates whether the input termination is Off or On. Press the INPUT TERM
button to toggle the setting.

Input Sample Rate
Indicates the sample rate of the input signal from 32 through 192 kHz.

Word Length
Indicates the Word Length of the input signal from 16 through 24 bit.

Digital Errors
Indicates four main error conditions encountered in digital signals as an aid to
troubleshooting,

Re-Clocking
Indicates Input Re-Clocking On or Off. Press the RE-CLOCKING button to toggle
the setting.

Mode
Indicates whether input signal is Pro or Consumer mode.

Input EQ
Enables automatic input equalization. LOCKED indicates input data is present
and acceptable. ENABLED indicates equalization is applied. Press the INPUT
EQ button to enable automatic equalization.

Input Select
The Input Select switch has four modes of operation. Press the Input Select
switch repeatedly to advance through the four following operating modes:

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Mode

LEDs On

Function

1

1

Unit operates as Dual 1X6, front panel
displays and controls Input 1

2

2

Unit operates as Dual 1X6, front panel
displays and controls Input 2

3

1 & Bridge

Unit operates as 1X12 using Input 1 as
source; front panel displays and controls
Input 1

4

2 & Bridge

Unit operates as 1X12 using Input 2 as
source; front panel displays and controls
Input 2

DDA212 Series 2 units retain their last operating mode even if power is
interrupted.

Front Panel Lock
Press and hold the FRONT PANEL LOCK button to lock all the front panel
controls. Press and hold again to unlock.

TRANSMITTERS
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 is less than 25 nanoseconds even at the lowest
sample rate.

OUTPUT DRIVERS
DDA-212XLR units are equipped with balanced, 110-ohm, transformer coupled

outputs and XLR type connectors. DDA-212BNC 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.

POWER SUPPLY

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.

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.

POWER

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.

WIRING

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
INPUTS

Connectors: 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

Termination: Terminating resistors may be switched in or out from front

panel

Cable Length: 300m of 110-ohm cable, 1000 m of 75 ohm coax (with

equalizer)

Equalizer: Automatic via front panel actuation button, independent for

Inputs 1 or Input 2
Sample Rates: Accepts 27kHz to >192kHz
Clock: With re-clocking on, regenerated from input signal; clock

jitter <300 picoseconds peak-to-peak at 96kHz sample rate
With re-clocking off, input clock is passed directly to outputs

OUTPUTS

Connectors: 12 x XLR male or 12 x BNC chassis mount
Levels: XLR, 4Vp-p loaded at 110 ohms

BNC, 2Vp-p loaded at 75 ohms
Impedances: XLR: 110 ohms, balanced, transformer isolated

BNC: 75 ohms, unbalanced
Output Jitter: <300 picoseconds peak to peak at 96kHz sample rate
Propagation Delay: <25 nanoseconds
POWER Internal supply, 115/230VAC+/-10%, 50/60Hz, 10VA,

IEC320 3 pin connector

SIZE 1 RU, 19”(48.3cm) W X 1.75”(4.5cm) H X 8.5”(21.6cm) D
WEIGHT 7 lbs (3.2kg) net; 9 lbs (4.1kg) shipping weight
MODELS: DDA-212XLR

DDA-212BNC

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One Year Limited Warranty

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.

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.

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.

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

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.

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.

ATI DISCLAIMS ANY WARRANTIES, 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,
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.

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.

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

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

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