ATI Audio DA206 Operating instructions

ATI Audio Inc. ■ Tel: [phone] ■ Fax: [phone] ■[e-mail] ■ www. audio.com
DA206 AND DA412
ANALOG AUDIO
DISTRIBUTION AMPLIFIERS
OPERATING AND MAINTENANCE MANUAL
© Copyright 2011, ATI Audio Inc.

ATI Audio Inc. ■ Tel: [phone] ■ Fax: [phone] ■[e-mail] ■ www. audio.com
DESCRIPTION
The DA206 and DA412 Analog Audio Distribution Amplifiers provide two (DA206)
or four (DA412) 1X3 distribution amplifier channels with balanced inputs and
outputs. A master gain adjustment for each channel controls all three outputs
together to adjust for varying inputs, while individual trimmers for each output
allow adjustment over a 20dB range to accommodate -10dbu semi-pro up to
+8dBm line levels.
Another of the DA206 and DA412 Distribution Amplifiers many claims to fame is
the use of XLR type input and output connectors. XLRs are easy to use but make
paralleling inputs for 1X6 or 1X12 operation difficult. However, if you look under
the hood (remove the top cover) you will find some convenient jumper plugs that
allow you to parallel inputs A and B (P4 & P5), B and C (P6 & P7), C and D (P10
& P11), individually or simultaneously. If you are making a stereo 1X6 DA, drive
inputs A and C with Left and Right signals and jumper inputs A to B and C to D.
You can use the empty input connectors to loop-thru to the other dozen ATI
distribution amps that we hope you are using.
A rugged NE5532 IC forms the quiet, clean, gain selectable, 20Kohm
instrumentation amplifier input stage with good common mode hum rejection. An
internal gain selection jumper plug for each input (P2, P3, P8, P9) lets you
optimize for nominal inputs at -20dBu, -10dBu or +4dBu. Inputs up to +24dBu will
not clip in the +4dBu position and input signals exceeding +24dBu will clip
cleanly with no hang-up or phase reversal.
An LF347N quad bi-fet opamp forms the three variable gain output adjustment
stages. These variable gain stages use a unique circuit arrangement that allows
us to provide a smooth, logarithmic gain control for each output using an
inexpensive (but good) linear cermet potentiometer. Since we actually reduce the
stage gain for low outputs rather than taking the more conventional approach of
reducing the input level to a fixed gain amplifier, you can use the DA at low
output levels with very little noise penalty. You can use the DA to match console
medium level inputs (-20dBu) or to drive semi-pro IHF inputs without requiring
outboard attenuator pads.
SSM2142 active balanced output drivers sense the voltage on their high and low
output lines and will shut off drive to a grounded output line while doubling the
drive on the other. This capability allows you to connect the outputs to balanced
or unbalanced loads without regard to whether or which side of the output is
grounded. Maximum output at clipping is +22dBm into balanced loads; however,
even though the gain is the same under either condition, clipping output is
reduced by 6dB when driving an unbalanced load since the full output swing
capability of only one driver of the two is available.
Your DA206 or DA412 operates from a bipolar 15VDC regulated power supply.
The power supply is designed for minimum susceptibility to power line transients
and conducted RFI using ferrite beads, double bypassing and a non-concentric
wound semi-toroidal transformer.

ATI Audio Inc. ■ Tel: [phone] ■ Fax: [phone] ■[e-mail] ■ www. audio.com
INSTALLATION
MOUNTING
Your DA is designed for rack mounting on standard EIA 1-3/4 inch centers. Each
unit dissipates approximately 10 watts and is designed for use in an office
environment. Avoid excessive heat buildup (such as might be due to nearby
power amplifiers in unventilated racks) to ensure maximum component life.
AUDIO CONNECTIONS
XLR inputs and outputs are wired with pins 2 as HI and pins 3 as LOW. Pin 1
(shield) of all input and output connectors are permanently grounded in
accordance with current AES recommendations. The pin 1 grounds are routed
via a large, low impedance ground path directly to the chassis separately from
any audio ground paths. Internal circuit ground is also connected to the chassis
for shielding through an independent path. AC ground (green wire) is also
separately grounded to the chassis. Active balanced outputs require a reference
ground connection to the receiving device for proper operation. This ground is
carried through pin 1. If the pin 1 shield ground is not carried through to the
receiving device, the AC ground, rack frame, or studio ground system may
complete this ground. Noisy grounds require excellent common mode rejection in
the receiving device for quiet system operation.
We have taken measures to keep RFI out of your DA, including split and
bypassed input networks, beaded, bypassed and isolated power inputs,
nonconcentric wound, semi-toroidal power transformers, double ground plane PC
boards and a nice enclosure to keep rain and snow off the circuit boards.
However, in difficult broadcast applications, the RF shielding and suppression
system can be no better than the ground system into which it is trying to dump
the unwanted RF. For optimal product performance, be sure to have a good
grounding system
ADJUSTMENTS
The Master and individual Output level controls should all be set close to 2
o’clock to provide nominal +4dBm outputs for a nominal +4dBu input. These
settings allow +6/-16dB output adjustment range around nominal, which will allow
outputs of +10 to -12dBm to be set. In addition, the Master gain has +10dB to
OFF adjustment range to compensate for input level variations from -6dBu to
input clipping at +24dBu.
Changing the position of the input gain compensates for lower level inputs by
setting jumper plugs P2, P3, P8 and P9. These plugs add 14 or 24dB of extra
gain to permit nominal inputs of -20dBu and minimum inputs as low as -30dBu
for +4dBm out.
The input paralleling jumper plugs (P4 & P5, P6 & P7, P10 & P11) are located
under the cover just behind the input XLR connectors. They must be used in

ATI Audio Inc. ■ Tel: [phone] ■ Fax: [phone] ■[e-mail] ■ www.
audio.com
pairs (e.g.; P4 & P5 together) to properly jumper HI & LO input lines. These
jumper plugs let you use a DA206 as a Dual 1X3 or a Mono 1X6, and a DA412
as a Quad 1X3, Stereo 1X6 or a Mono 1X12 DA.
230VAC OPERATION
Your DA is wired for 115VAC, 50/60Hz operation unless otherwise requested at
time of order. It can be easily modified for 230VAC operation by removing the
power transformer primary jumpers W1 & W3 and inserting a jumper wire in
position W2. Different types of attachment plugs or line cords may be required for
connection to alternate supply voltages.
MAINTENANCE
Power supply voltages are regulated by A1 and A2 to +15 and -15VDC
respectively. IC output DC voltages under no signal, shorted input conditions
should remain within 0.1VDC of ground. A greater deviation is an indicator of IC
or circuit problems.
Inputs and outputs are susceptible to high common mode and differential AC and
DC voltages fed from external devices or appearing on ground.
UL LISTING
The DA206 and DA412 are listed by Underwriter Laboratories as “Listed
Professional Audio Equipment 2D65.”

ATI Audio Inc. ■ Tel: [phone] ■ Fax: [phone] ■[e-mail] ■ www.
audio.com
SPECIFICATIONS FOR DA206 AND DA412
OUTPUT LEVEL: +22dBm peak into 600 ohm balanced load
+18dBm peak, typical, into unbalanced loads
DISTORTION: THD .10% maximum, 20 to 20,000Hz at peak output
IMD .05% maximum, SMPTE measurement
SLEW RATE: 13 Volts per microsecond
RESPONSE: ± .25dB, 20 to 20,000Hz
NOISE: -95dBm out at maximum gain, 20kHz bandwidth
GAIN: 40dB maximum
CROSSTALK: 70dB minimum at 10kHz, any path
OUTPUT ISOLATION: 70 dB minimum at 1kHz. A shorted output does not
affect any other output.
OUTPUTS: Active balanced, servo controlled, ground sensing, 50
Ohm output impedance, DC coupled. XLR type male
connectors, Pin 2-HI, 3-LO, 1-GND.
INPUTS: 20Kohm active balanced, split and RF bypassed.
+22dBm maximum input level, 60dB CMR at 60Hz.
XLR type female connectors, Pin 2-HI, 3-LO, 1-GND.
POWER: 115/230 VAC ±10%, 47 - 63Hz, 20VA; use .5A,
250VAC fuse, UL listed, ¼ D x 1-1/4 inches long
SIZE: 19” (48.3cm) W X 1.75” (4.45cm) H X 7.5” (19cm) D
SHIPPING WEIGHT DA206: 5 lbs. (2.3kg)
DA412: 6 lbs. (2.7kg)
MODELS AVAILABLE: DA206 Dual 1X3 Active balanced outputs
DA412 Quad 1X3 Active balanced outputs

ATI Audio Inc. ■ Tel: [phone] ■ Fax: [phone] ■[e-mail] ■ www.
audio.com
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 [email protected] 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.