Art SDA-1 Operating instructions

SDA-1
STUDIO DIGITAL AMPLIFIER
USER’S GUIDE

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The ART
SDA-1 Studio Digital Amplifier
TABLE OF CONTENTS
IMPORTANT SAFETY INSTRUCTION – READ FIRST.......................................................................3
INTRODUCTION ..................................................................................................................................4
ADVANTAGES ..................................................................................................................................4
FEATURES........................................................................................................................................5
INSTALLATION....................................................................................................................................6
AC POWER HOOKUP.......................................................................................................................6
AUDIO CONNECTIONS....................................................................................................................6
OPERATION PRECAUTIONS...........................................................................................................6
CONTROLS & INDICATORS – FRONT PANEL..................................................................................7
POWER SWITCH ..............................................................................................................................7
CHANNEL ATTENUATORS..............................................................................................................7
SIGNAL LED INDICATOR.................................................................................................................7
CLIP LED INDICATOR ......................................................................................................................7
PROTECT LED INDICATOR.............................................................................................................7
REAR PANEL CONNECTIONS...........................................................................................................8
INPUTS..............................................................................................................................................8
¼” INPUT JACKS ..............................................................................................................................8
XLR INPUT JACKS............................................................................................................................8
AMP MODE SWITCH ........................................................................................................................8
OUTPUT BINDING POST..................................................................................................................9
FUSE .................................................................................................................................................9
AC POWER INPUT............................................................................................................................9
OPERATION.......................................................................................................................................10
NORMAL OPERATION....................................................................................................................10
MONO BRIDGE OPERATION.........................................................................................................10
PROTECTION .................................................................................................................................10
WARRANTY INFORMATION.............................................................................................................12
LIMITED WARRANTY .....................................................................................................................12
EXCLUSIONS..................................................................................................................................12
SERVICE............................................................................................................................................13
SDA-1 SPECIFICATIONS..................................................................................................................14

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IMPORTANT SAFETY INSTRUCTION – READ FIRST
This symbol, whenever it appears, alerts you This symbol, wherever it appears, alerts
to the presence of uninsulated dangerous you to important operating and maintenance
voltage inside the enclosure-voltage that instructions in the accompanying literature.
may be sufficient to constitute a risk of shock. Read read manual.
Read instructions: Retain these safety and operating instructions for future reference. Heed all warnings
printed here and on the equipment. Follow the operating instructions printed in this user guide.
Do not open: There are no user serviceable parts inside. Refer any service work to qualified technical
personnel only.
Power sources: Connect the unit to mains power only of the type described in this user guide or marked on
the rear panel. The power source must provide a good ground connection.
Power cord: Use the power cord with sealed mains plug appropriate for your local main supply as provided
with the equipment. If the provided plug does not fit into you outlet consult your service agent. Route the power
cord so that it is not likely to be walked on, stretched or pinched by items placed upon or against.
Grounding: Do not defeat the grounding and polarization means of the power cord plug. Do not remove or
tamper with the ground connection on the power cord.
Ventilation: Do not obstruct the ventilation slots or position the unit where the air required for ventilation is
impeded. If the unit is to be operated in a rack, case or other furniture ensure that it is constructed to allow
adequate ventilation.
Moisture: To reduce the risk of fire or electrical shock do not expose the unit to rain, moisture or use in damp
or wet conditions. Do not place container of liquid on it, which may spill into any openings.
Heat: Do not locate the unit in a place close to excessive heat or direct sunlight, as this could be a fire hazard.
Locate the unit away from any equipment, which produces heat such as: power supplies, power amplifiers and
heaters.
Environment: Protect from excessive dirt, dust, heat, and vibration when operating and storing. Avoid tobacco
ash, drink spillage and smoke, especially that associated with smoke machines.
Handling: To prevent damage to the controls and cosmetics avoid rough handling and excessive vibration.
Protect the controls from damage during transit. Use adequate padding if you need to ship the unit. To avoid
injury to yourself or damage to the equipment take care when lifting, moving or carrying the unit.
Servicing: Switch off the equipment and unplug the power cord immediately if it is exposed to moisture, spilled
liquid, objects fallen into opening, the power cord or plug becomes damaged during a lightning storm or if
smoke odor or noise is noted. Refer servicing to qualified technical personnel only.
Installation: Install the unit in accordance with the instruction printed in the user guide.

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INTRODUCTION
Thank you for purchasing an ART SDA-1 Studio Digital Amplifier - and
congratulations: you now own one of the most versatile amplifiers available.
Offering a superb level of sound quality, the SDA-1’s clean and powerful
circuitry combined with a straightforward user interface quickly and easily
delivers the power you need for professional and project studio monitoring.
Why would you choose a Digital switching amp over an Analog Linear amp.
Theoretical power efficiency of class D amplifiers is 100%. That is to say, all
of the power supplied to it is delivered to the load, none is turned to heat.
This is because an ideal switch in its on state will conduct all current but has
no voltage across it, hence no heat is dissipated. And when it is off, it will
have the full supply voltage standing across it, but no current flows through
it. Again, no heat is dissipated. Real-life power MOSFETs are not ideal
switches, but practical efficiencies well over 90% are common. By contrast,
linear AB-CLASS amplifiers are always operated with both current flowing
through and voltage standing across the power devices. An ideal class B
amplifier has a theoretical maximum efficiency of 78%.
Advantages
Despite the complexity involved, a properly designed class D switching
amplifier offers the following benefits:
Reduction in size and weight of the amplifier,
Reduced power waste as heat dissipation and hence smaller (or no)
heat sinks,
No need for internal fan cooling,
Reduction in cost vs. weight due to smaller heat sink and compact
circuitry,
Very high power conversion efficiency, usually better than 90% above
one quarter of the amplifier's maximum power, and 50% or better at
low power levels.

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Features
• Studio Digital Audio Amplifier
• High Efficiency Switching Amplifier and Power Supply
• Lighter and Cooler than Conventional Audio Amplifiers
• Extremely Low Noise and Distortion Design
• 140 Watts/Channel @ 8 Ohms
• 200 Watts/Channel @ 4 Ohms
• 400 Watts/Bridged Mono @ 8 Ohms
• 280 Watts/Bridged Mono @ 70 V line operation
• 20 Hz to 20 kHz within +/- 0.5dB
• XLR & ¼” Inputs
• Multi-Way Binding Post Outputs
• Recessed “Pop Out” Detented Attenuator Knobs
• Low Profile 1U Rackmountable Design
• All Steel and Aluminum Chassis
• Perfect for Pro and Project Studios

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INSTALLATION
The SDA-1 may be used in a wide variety of project and professional
studio environments. Self-contained in a steel and aluminum
enclosure, the unit is designed for many years of use. For greater
reliability, we recommend that you not place the unit directly under or
on top of other sources of heat. It is important that any rack-mountable
unit is properly ventilated, and the SDA-1 is no exception.
AC Power Hookup
The SDA-1 has an internal switching power supply designed to operate
at 90-125 VAC @ 50-60 Hz. Units manufactured for use outside the
United States of America have been modified to comply with the
required electrical specifications
Audio Connections
Audio connections to and from the SDA-1 are balanced XLR [Pin 2 =
Hot (+), Pin 3 = Cold (-), Pin 1 = (Ground)] and balanced or
unbalanced ¼” [Tip = Hot (+), Ring = Cold (-), Sleeve = (Ground)].
Operation Precautions
Warning: For optimum performance and reliability when running high
continuous signal levels, do not operate the amplifier with a speaker
load of less than 4 Ohms per channel, or any combination of speakers
that together are less than 4 Ohms.
Using one speaker per channel, it must be rated at 4 or more Ohms.
Using two speakers per channel in parallel, they must each be rated at
8 or more Ohms. When in Bridge Mode, the speaker should be rated at
8 or more Ohms.
The amplifier will tolerate 2 Ohm (stereo), 4 Ohm (bridged mono) loads
but running into this low of impedance may cause the protection
circuitry to engage during continuous high-level bass passages.

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CONTROLS & INDICATORS – FRONT PANEL
Power Switch
The Power Switch is located on the front of the unit, directly in the
center. During initial installation, make sure the attenuators for each
channel are set to a low volume level before applying power.
Channel Attenuators
The dials for channel one and channel two’s volume attenuators are
located to the left and right of the Power Switch. When set to zero (fully
clockwise), there is no attenuation of volume. As the attenuation
amount increases by turning counterclockwise, the volume is reduced.
Full attenuation is at -infinity. The attenuators are calibrated in dB.
Signal LED Indicator
This LED indicates that a signal is present. The LED will glow when the
amplifiers output signal is within approximately 30dB of full scale.
Clip LED Indicator
This LED indicates that the Power Amp is clipping. This LED comes on
when the output signal from the amplifier begins to distort. When there
is significant clipping, lower the input gains to reduce clipping, as well
as the risk of damage to the amplifier and speakers/monitors.
Protect LED Indicator
The LED will glow when the channel goes into protect mode. In protect
mode, the output signal to the speakers will be muted (channel
specific). If there is a fault condition at the speaker outputs (due to a
severe load or short) the LED will light until the fault is removed.

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REAR PANEL CONNECTIONS
It is easy to interface the SDA-1 with a wide variety of equipment. All inputs
and outputs are located on the rear panel. Standard ¼” and XLR inputs and
binding post outputs make patching simple.
Inputs
The SDA-1 has two styles of input connections: XLR and ¼”. Use
these connections to connect the output signal from a mixer,
preamplifier, crossover, or EQ to the amplifier. The balanced XLR
connection is recommended for cable runs longer than 20 feet. For
cable runs under 20 feet, the ¼” option may be preferable.
You may also use the two different types of input cables to jump a
parallel connection to another amp. For example: connect an XLR
cable to the input of channel one, then connect a ¼” cable to the input
jack of channel one and jump that cable to the input of another amp.
¼” Input Jacks
The ¼” Input jacks are wired as follows: Tip is positive, Ring is
negative, and Sleeve is ground. This connection can be used for both
balanced and unbalanced connections.
XLR Input Jacks
The XLR Input jacks are Pin Two positive, Pin Three negative, and Pin
One is ground. This connection is for balanced connections.
Amp Mode Switch
The SDA-1 Amp Mode Switch allows you to choose between Stereo

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Mode and Bridge Mono Mode. Make sure that power is off and that
your speakers are wired appropriately when changing this mode.
Output Binding Post
The SDA-1 Outputs for channels one and two are multi-connection
jacks. You can use banana jacks, spade connectors or bare wire.
Bare Wire Connections – unscrew the red and black caps on the
binding posts (don’t completely remove). Strip back the wire cable
insulation ½”, then inset the bare wire into the hole on the top of the
plastic assembly. Once it is in, screw the binding post cap down on the
wire. Be sure the wire connected to one post does NOT come in
contact with that of another.
Spade Connector – Unscrew the red and black caps on the binding
posts (don’t completely remove). Insert the spade connector into the
binding post and tighten the caps down on the spade connector. Be
sure the wire connected to one post does NOT come in contact with
that of another.
Banana Plug – Insert the banana jacks into the caps of the binding
posts. Be sure that the red and black caps on the binding posts are
tightened down completely and that they are securely connected to
avoid the possibility of them popping out.
Fuse
The SDA-1 utilizes a (T7A 250v 20mm) 7Amp fuse (USA version). Be
sure to replace any blown fuses with a fuse of equal rating only.
AC Power Input
The SDA-1 features an internal switching power supply. Plug the
detachable cable into a standard wall outlet. Be sure that the supplied
voltage matches that of the required voltage of your amplifier. Never
plug the amp into an outlet that does not match the required voltage of
your amplifier. Serious damage could result.

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OPERATION
The main application of the SDA-1 is as a studio power amplifier for
powering monitors. Plug audio source material directly into the inputs
and set the output controls to provide an appropriate level into the next
stage of your system.
Normal Operation
For a typical stereo setup, connect the source (mixer, eq, etc) outputs
into channels one and two of the amplifier. Connect your speakers to
the outputs on the rear of the amplifier. Be sure that your front gain
controls are turned down to their lowest level (full counter-clockwise).
Turn the amp on, then slowly turn the input level up. Use your front
gain controls to regulate the output volume. Be sure not to raise the
volume to the clip level; however, an intermittent clip signal is
acceptable.
Mono Bridge Operation
Be sure the amp is shut off. Press the Stereo/Bridge switch (on the
back) to the “in” position. Connect an input signal to channel one.
Connect your speaker across the red output binding post on the rear of
your amplifier. Turn your equipment on – your amplifier should be the
last piece you turn on (be sure it’s volume is turned down). Apply an
input signal to your amplifier. Use channel one’s attenuator to adjust
your amplifier output level.
Protection
The SDA-1’s output circuitry is fully protected from shorts circuits. An
ultrasonic filter network decouples RF from the output and helps keep
the amplifier stable with reactive loads.

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The SDA-1’s heatsinks do most of the work in getting heat away from
the amplifier. If, in the unlikely event the heatsink should reach 85
degrees Celsius, the amplifier will mute and disconnect the outputs,
until it cools down enough for safe operation. Make sure there is
adequate ventilation around the heatsinks if you plan on rack mounting
the SDA-1 in an enclosed space.
The SDA-1 is fully protected from shorts, opens, over-current, and
over-voltage. A relay disconnects the outputs under any fault
conditions and automatically returns to normal operation once the fault
is removed.
The amplifier is stable into loads as low as 2 ohms (stereo mode), and
4 ohms (bridged mono mode) when used in a fixed or permanent
installation. However, for continuous operation at high signal levels, the
amplifier should be operated with a minimum load of 4 Ohms per
channel in stereo mode and 8 Ohms in bridged mono mode, otherwise
the overload and thermal protection circuitry may cycle the amplifier on
and off as it protects itself during continuous extreme bass peaks.

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WARRANTY INFORMATION
Limited Warranty (USA only)
Applied Research and Technology will provide warranty and service for this
unit in accordance with the following warrants:
Applied Research and Technology, (ART) warrants to the original purchaser
that this product and the components thereof will be free from defects in
workmanship and materials for a period of three years from the date of
purchase. Applied Research and Technology will, without charge, repair or
replace, at its option, defective product or component parts upon prepaid
delivery to the factory service department or authorized service center,
accompanied by proof of purchase date in the form of a valid sales receipt.
Exclusions
This warranty does not apply in the event of misuse or abuse of the product
or as a result of unauthorized alterations or repairs. This warranty is void if
the serial number is altered, defaced, or removed.
ART reserves the right to make changes in design or make additions to or
improvements upon this product without any obligation to install the same
on products previously manufactured.
ART shall not be liable for any consequential damages, including without
limitation damages resulting from loss of use. Some states do not allow
limitations of incidental or consequential damages, so the above limitation or
exclusion may not apply to you. This warranty gives you specific rights and
you may have other rights, which vary, from state to state. The warranty
terms listed above are only valid within the United States of America.
For units purchased outside the United States, an authorized distributor of
Applied Research and Technology will provide service. For information on
warranty and service policies outside the U.S., please contact your local
distributor.

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SERVICE
The following information is provided in the unlikely event that your unit
requires service.
1) Be sure that the unit is the cause of the problem. Check to make sure the
unit has power, all cables are connected correctly, and the cables
themselves are in working condition. You may want to consult with your
dealer for assistance in troubleshooting or testing your particular
configuration.
2) If you believe that the ART unit is at fault, go to www.artproaudio.com.
Select “Support”, then “Return Authorization Request” to request a return
authorization number.
3) If you are returning the unit for service, pack the unit in its original carton
or a reasonable substitute. The original packaging may not be suitable as a
shipping carton, so consider putting the packaged unit in another box for
shipping. Print the RA number clearly on the outside of the shipping box.
Print your return shipping address on the outside of the box.
4) Include, with your unit, a note with the RA number and your contact
information, including a return shipping address (we cannot ship to a P.O.
box) and a daytime phone number, and a description of the problem,
preferably attached to the top of the unit. Also include a copy of your
purchase receipt.
Fill in the following information for your reference:
Date of purchase ___________________
Purchased from ___________________
Serial number ___________________

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SDA-1 SPECIFICATIONS
Dimensions 1.75"H x 19.0" W x 9.5"D
Stereo Output Power, 8 Ohms 140 Watts RMS /Ch
Stereo Output Power, 4 Ohms 200 Watts RMS /Ch
Stereo Output Power, 2 Ohms 100 Watts RMS /Ch
Stereo Output Power, 16 Ohms 80 Watts RMS /Ch
Bridged Output Power, 8 Ohms 400 Watts RMS mono
Bridged Output Power, 16 Ohms 280 Watts RMS mono
Bridged Output Power, 4 Ohms 200 Watts RMS mono
Bridged Output Power, 70V line 280 Watts RMS 70Vline
Minimum Load Impedance 2 Ohms /Ch, 4 Ohms mono
CMRR >60dB (typical @ 1kHz)
Frequency Response 20Hz to 20kHz, +/- 0.5dB
Total Harmonic Distortion (THD) <0.05% (typical)
Hum and Noise A-weighted >95dB below Clipping
Input Sensitivity for full power 0.707 Volt
Idle current (120Volt AC Mains) 0.23 Amp (29 Watts)
Weight 7.5 lbs, 3.4 kg
AC Supply Type Digital Switching (~48 kHz)
Amplifier Type Digital Switching (~435kHz)
Overall Efficiency >78% @ full power
(4 & 8 Ohm operation)
Power Requirements USA –90-125VAC 50-60Hz 875VA(max.)
EUROPE –230VAC 50Hz-60Hz 875VA(max.)
Export units configured for country of
destination.
ART maintains a policy of constant product improvement. ART reserves the right to
make changes in design or make additions to or improvements upon this product
without any obligation to install same on products previously manufactured. Therefore,
specifications are subject to change without notice.

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www.artproaudio.com
E-mail: [email protected]
© 2013 Applied Research & Technology
156D5004101