Art SLA-4 User manual
SLA-4
FOUR CHANNEL STUDIO LINEAR AMPLIFIER
USER’S GUIDE
2
The ART SLA-4
FOUR CHANNEL STUDIO LINEAR AMPLIFIER
IMPORTANT SAFETY INSTRUCTIONS - READ FIRST ....................... 4
INTRODUCTION ..................................................................................... 5
INSTALLATION ................................................................................... 6-7
AC Power Hookup ............................................................................... 6
Audio Input Connections ..................................................................... 6
Speaker Load Safety Precautions ....................................................... 6
Security Cover ......................................................................................7
CONTROLS AND INDICATORS – FRONT PANEL ............................8-9
Power Switch ....................................................................................... 8
Channel Level Controls ....................................................................... 8
Signal Indicator LED ........................................................................... 8
Clip Indicator LED ............................................................................... 8
Protect Indicator LED .......................................................................... 9
REAR PANEL CONNECTIONS ...................................................... 10-13
Inputs ................................................................................................. 10
¼” Input Jacks ................................................................................... 10
Euroblock Barrier Strips .....................................................................10
Stereo / Bridge Amp Mode Switches ................................................ 11
Output Binding Post ..................................................................... 11-12
SmartFan™ ....................................................................................... 12
Fuse .................................................................................................. 13
AC Power Input ................................................................................. 13
OPERATION .................................................................................... 14-15
WARRANTY INFORMATION ............................................................... 16
SERVICE ............................................................................................... 17
SLA-4 SPECIFICATIONS ..................................................................... 18
3
IMPORTANT SAFETY INSTRUCTIONS – READ FIRST
This symbol, whenever it appears, This symbol, wherever it appears, alerts
alerts you to the presence of uninsulated you to important operating and maintenance
dangerous voltage inside the enclosure. Voltage instructions in the accompanying literature.
that may be sufficient to constitute a risk of shock. Please read manual.
Read instructions: Retain these safety and operating instructions for future reference. Heed all
warnings printed here and on the equipment. Follow 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: Only connect unit to mains power of type marked on rear panel. Power source must
provide a good ground connection.
Power cord: Use the power cord with sealed mains plug appropriate for your local mains supply as
provided with the equipment. If the provided plug does not fit into your 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 a 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 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.
4
INTRODUCTION
Thank you for purchasing the ART SLA-4 Four Channel Studio Linear
Amplifier and congratulations, you now own one of the most versatile linear
audio amplifiers available. Offering a superb level of sound quality, the SLA-
4’s clean and powerful linear circuitry combined with a straightforward user
interface quickly and easily delivers the power you need for professional
audio applications.
Features:
• Extremely Low Noise, Discrete Linear Design
• 4 x 100 Watts/Ch @ 8 Ohms, 140 Watts/Ch @ 4 Ohms
• 2 x 200 Watts/Ch @ 16 Ohms, 280 Watts/Ch @ 8 Ohms (bridged)
• 2 x 100 Watts/Ch @ 8 Ohms & 1 x 280 Watts @ 16 Ohms (bridged)
• Toroidal Transformer
• 10 Hz to 40 kHz Frequency Response
• ¼” TRS, and Euroblock Balanced Inputs
• Recessed “Pop Out” Detented Gain Knobs
• Tamper-Proof Faceplate Included
• Multi-way Binding Post Outputs
• Low Profile 1U Rack-Mountable Design
• SmartFan Silent Cooling System
5
INSTALLATION
The SLA-4 may be used in a wide variety of applications from project
or professional studio environments to commercial sound installations.
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
SLA-4 is no exception.
AC POWER HOOKUP
The SLA-4 has an internal power supply designed to operate at 120
VAC @ 50 to 60 Hz. Units manufactured for use outside of North
America have been modified to comply with the required electrical
specifications.
AUDIO INPUT CONNECTIONS
Audio connections to the SLA-4 are balanced or unbalanced ¼” [Tip =
Hot (+), Ring = Cold (-), Sleeve = (Ground)].
Euroblock connections: can be wired balance or unbalanced.
See diagram on page 11
SPEAKER LOAD SAFETY PRECAUTIONS
Warning:
For optimum performance and reliability, 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 Ohms or greater.
When using two speakers per channel, in parallel, they must each be
rated at 8 Ohms, or greater.
When in bridge mode, the speaker load should be 8 Ohms, or greater.
6
SECURITY COVER
For commercial installations it may be desirable to set the gain controls
on the power amp, and then make them inaccessible to non-qualified
operators. This can be accomplished by using the Security Cover Plate
that is included with the SLA-4.
Simply set the channel level controls to the desired gain settings and
press the knobs into the chassis until they lock into their recessed
position. Then remove the two small phillips head screws, one on each
side of the four channel level controls. Use these same screws to
attach the security cover plate to the front panel, thereby covering the
four channel level controls, making them tamperproof.
See diagram below
7
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 level controls for each
channel are set to a low volume level before applying power.
CHANNEL LEVEL CONTROLS
The dials for the four channel level controls are located to the left and
right of the Power Switch. When set to zero (fully clockwise), the level
is at maximum. The level is reduced as you turn the control
counterclockwise. Full attenuation is at – infinity. The level controls are
detented and calibrated in dB.
SIGNAL INDICATOR LED
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 INDICATOR LED
This LED indicates that the power amp is near clipping. This LED
comes on when the output signal from the amplifier begins to distort. If
there is significant clipping, lower the input levels to reduce clipping, as
well as the risk of damage to the speakers/monitors.
8
9
PROTECT INDICATOR LED
The LED will glow when the channels associated with it go 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.
Channels One and Two share a Protect LED, as do channels Three
and Four on the SLA-4.
The protect lights will also light during power up and down, to indicate
that the signal is muted.
REAR PANEL CONNECTIONS
It is easy to interface the SLA-4 with a wide variety of equipment. All inputs
and outputs are located on the rear panel. Standard ¼” and Euroblock
inputs and binding post outputs make patching simple.
INPUTS
The SLA-4 has two styles of input connections: ¼” TRS and Euroblock.
Use these connections to connect the output signal from a mixer,
preamplifier, crossover, or EQ to the amplifier. Balanced connections
are recommended for cable runs longer than 20 feet. For cable runs
under 20 feet, the unbalanced connections can be used.
You may also use the two different types of input connections to jump
a parallel connection to another amp. For example: connect a ¼” cable
to the input of channel one, and then connect from the Euroblock
connections to another amplifier channel input.
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.
EUROBLOCK BARRIER STRIPS
Insert wires into the barrier strip, and then snug down with the
setscrew. Each barrier strip can be removed for quick service without
disconnecting the individual wires.
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