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INSTALLATION & OPERATION GUIDE
B LENDING H IGH F IDELITY AND A RCHITECTURE
™
Systems Integration Amplifier
™
®
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CONGRATULATIONS!
Thank you for purchasing the Niles SI-245, one of the most flexible and convenient amplifiers ever offered. Like all Niles products, the SI-245 is built to the
highest standards of quality control and reliability. With proper installation and
operation, you'll enjoy years of trouble-free use.
Niles manufactures the industry's most complete line of custom installation components and accessories for audio/video systems. For a free full line catalog write:
Niles, Catalog Request, P.O. Box 160818, Miami, Florida 33116-0818
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TABLE OF CONTENTS
INTRODUCTION 2
FEATURES AND BENEFITS 3
INSTALLATION CONSIDERATIONS 5
FRONT AND REAR PANELDETAILS 9
INSTALLATION 11
OPERATION 15
TROUBLESHOOTING GUIDE 16
SPECIFICATIONS 18
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INTRODUCTION
The SI-245 is a member of the award-winning Niles Systems Integration Amplifier
family. It is designed for use in home theaters and whole house audio systems,
and is especially suited for use as a “zone” amplifier. Niles specifically designs
Systems Integration Amplifiers to solve the problems installers face when integrating different brands and models of equipment into various acoustic environments in home theater, stereo, and background music applications. The SI-245
brings extremely high-current power to a custom installed A/V System in a
remarkably convenient way.
INTRODUCTION
2
SI-245
Systems Integration Amplifier
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FEATURES AND BENEFITS
Real World Power
The SI-245 delivers 45 watts per channel at 8 Ohms and 70 watts per channel at
4 Ohms. You’ll get tremendous bass and dynamics from every pair of speakers
powered by an SI-245.
Transparent Sound
The audio circuitry of the SI-245 is constructed using the finest parts available;
including 1% metal film resistors, high quality capacitors, and oversized heat sinks.
All this attention to technical detail creates a sound that is clear and uncolored with
phenomenal imaging.
Freedom From Crosstalk
Each channel of the SI-245 is powered via its own independent power supply. This
increases the isolation between the two channels, and minimizes cross talk guaranteeing you absolute silence as the backdrop to your music.
Current For Reactive Loads
The high current design of the SI-245 assures that even unusual and reactive loads are
handled with aplomb (a massive toroidal transformer with two separate windings, one
for each of the independent power supplies, provides more than ample current
to your system).
Freedom from Fan Noise
The oversized heat sinks inside the SI-245 allow the amplifier to stay cool even when
operating into low impedance loads—without the noise of fan-cooled amplifiers.
Independent Level Controls
Each channel has its own independent level control enabling you to precisely
match the SI-245 to the rest of your system. The level controls also enable you to
limit the volume, preventing abuse of the system.
Lifetime Connections
The SI-245 features stereo inputs, cascade stereo outputs, and five-way binding
posts which are all gold plated to ensure perfect connections without corrosion for
years to come.
FEATURES AND BENEFITS
3
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Turn-On Modes
The SI-245 features three turn-on modes: 1. Music Sense 2. External Voltage Trigger
3. Manual Turn-On via the front panel switch. You can configure the SI-245 to interface with any kind of system and have the unit automatically turn on.
Automatic Protection
The SI-245 is equipped with sophisticated protection circuits. In the unlikely event
that a problem occurs, the amplifier shuts itself off. When conditions return to normal, regular operation resumes.
Status Display for Troubleshooting
LED's on the front panel indicate Power, Active Status, and a Protection W arning. With
a glance at the front panel, a troubleshooter is quickly provided with key information!
Control Output
A 12 volt DC output is provided whenever the amplifier is on, allowing you to
operate voltage-triggered devices like motorized screens and curtains.
Designed and Engineered in the USA
Limited two year parts and labor Warranty.
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FEATURES AND BENEFITS
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INSTALLATION CONSIDERATIONS
Placement
Place the SI-245 on a flat level surface like a table or shelf. It should be placed
upright so that its weight rests on the four attached feet. Placing the weight of the
amplifier on the rear or front panel for even an instant may result in damage to
the amplifier's connectors and controls.
The SI-245, like any hi-fi component, will last much longer if it is given adequate
ventilation for proper cooling. When installing the SI-245 in a cabinet, be sure
that the rear of the cabinet is open to fresh air to provide proper cooling (see
Figure 1). If the cabinet’s design will not accommodate an open rear, install two
small “boxer fans” to provide continuous air flow into and out of the cabinet (see
Figure 2). Place the SI-245 so that there is at least 5" of free air space above the
chassis. If the amplifier is located on a carpeted surface, place a board under the
amplifier's feet. Do not block the ventilation holes on the top and bottom of the
SI-245.
The SI-245 is equipped with an internal transformer, which generates a powerful
magnetic field which could induce hum in a turntable (particularly a turntable
equipped with a moving coil cartridge). Do not place a turntable directly above
or directly adjacent to the SI-245.
INSTALLATION CONSIDERATIONS
5
If the cabinet rear is not open to
fresh air, install two small “boxer
fans” to provide continuous air
flow into and out of the cabinet.
Make sure that there is a minimum
of 5” of free air space above the
amplifier for proper ventilation.
Allow a minimum of 2” of
depth behind unit to accommodate cables and connectors.
Figure 1
Figure 2
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Turn-On Modes
The SI-245 draws more current than a preamplifier’s switched AC outlet can safely supply. Also, your preamplifier may "thump" at dangerous volumes if the
amplifier is already on when the preamp turns on. It is usually best to turn the
amplifier on only when it is needed. The Turn-On Mode selector switch gives you
three options for turning the SI-245 on and off.
Constant - The auto turn-on circuitry is off. The front panel master power switch
operates the amplifier. In is "On", out is "Off".
Audio Sense - The master switch on the front panel must be in the "On" position.
The amplifier is off when there is no audio signal present at either the left or the
right input, but the sensing circuitry is on. The turn-on sensing circuitry looks for
a tiny amount of audio signal present at any of the audio inputs. If it detects a signal, the amplifier is turned on. Once the audio signal stops, the sensing circuit
waits three minutes, then turns the amplifier off.
3-30 Volt AC/DC Opto-Isolated Voltage Trigger - The master switch on the front panel
must be in the "On" position. The amplifier is off when there is no 3-30V AC or DC voltage detected at the trigger input. Once the sensing circuitry detects a voltage and a linelevel audio signal is detected at the input, the amplifier is turned on. Once the voltage
stops, the sensing circuit instantly turns the amplifier off. V oltage triggers can be supplied
by Niles automated switchers, some video projectors, some surround sound processors,
or something as simple as a 16 volt AC wall adapter (Niles XF00008) plugged into the
switched outlet of your stereo receiver . DO NOT USE ADC W ALLADAPTER. The long
discharge time of the DC adapter’s filter capacitor will delay the turn-off of the amplifier.
If you are using a wall adapter or external power supply to provide the trigger, it
doesn't have to be very large (a minimum current capability of 2.5 milliamps for a
3 volt trigger increasing up to a minimum of 38 milliamps for a 30 volt trigger).
INSTALLATION CONSIDERATIONS
6
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Multiple Speaker Loads
The SI-245 is stable into very low impedance loads. This means you can safely
operate three pairs of 8 ohm speakers (a 2.67 ohm load) directly connected to the
SI-245. Note that the SI-245 does not have on/off speaker switching built in.
When the amplifier is on, so are all of the speakers.
Niles makes a number of different speaker selection and impedance matching systems.
Speaker selection systems allow each pair of speakers to be turned on and off from your
equipment location (or even via remote control). That way, you know that the speakers in the bedroom are off so you can avoid waking a sleeping spouse! These speaker selectors provide an easy way to terminate all of the wires for more than three pairs.
Testing and troubleshooting a new system is much easier with the individual room
labels and on/off switches of a Niles speaker selection system. Additionally, Niles
speaker selection systems offer impedance matching features which will allow you to
connect up to ten pairs of speakers to your SI-245 amplifier.
INSTALLATION CONSIDERATIONS
7
NILES
Niles SI-245
Niles HDL-6 Speaker Selection System
Speaker selection systems allow each pair of speakers to be turned on and off from your
equipment location.
SPEAKER 6
Niles Audio
Corporation,Inc.
Miami, Florida USA
AMPLIFIER
L+ L- R- R+
L+ L- R- R+ L+ L- R- R+ L+ L- R- R+ L+ L- R- R+ L+ L- R- R+
ON OFF
CONSTANT
PROTECTION
SPEAKER 5 SPEAKER 4 SPEAKER 3 SPEAKER 2
SPEAKER 1
L+ L- R- R+
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INSTALLATION CONSIDERATIONS
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Cable and Wire
It will be easier to reconfigure or troubleshoot your system in the future if you
label the cables and wires for their destination or source, rather than which terminal of the SI-245 they are connected to.
The SI-245 connects to your preamp source via shielded line level audio cables
with RCA phono plugs. Use high quality cables with your Niles amplifier for the
lowest possible noise and best overall performance. Your Niles dealer can recommend the proper cable.
The SI-245 connects to your speakers using 2 conductor speaker wire. For most
applications, we recommend you use 16 or 18 gauge wire. For wiring runs longer
than 80 feet, we recommend 14 gauge wire. The binding posts of the
SI-245 will accommodate up to 12 gauge wire. Larger sizes can be accommodated
by attaching banana plugs to the wire. Note that the binding posts accept dual
banana or single banana connectors.
TECH TIP
Wire size is expressed by its AWG (American
Wire Gauge) number.The lower the number, the
larger the wire, i.e. twelve AWG is physically
larger than fourteen AWG.
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Red “Power” LED confirms the amplifier is
connected to a live AC power outlet. (and
that the master power switch is on).
Green “Active” LED lights when the
amplifier circuitry has been turned on by
the Turn-On circuits.
Front panel “Master Power” switch turns
off the entire amplifier, including the
Turn-On circuitry.
The red “Protect” LED indicates the amp has shut
down because there is a fault in a speaker, the
wiring, or with the SI-245 itself.
Main Inputs enable you to route a stereo
line level source to the SI-245.
Cascade Outputs of the Main Input enable
you to daisy chain multiple amplifiers.
3.5mm Mini Plug socket for
12v DC Control output.
"Turn-On Mode" switch
3.5mm Mini Plug socket
for voltage input.
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FRONT AND REAR PANEL DETAILS
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Binding posts for speaker
connections.
IEC receptacle for AC
power cord.
FRONT AND REAR PANEL DETAILS
10
Level Adjustment screws enable you to preset
the maximum system volume (or match levels
with another amplifier).
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INSTALLATION
Setting the Turn- On Mode Switch
The SI-245 has three turn-on modes. Select the mode you wish to use by sliding
the mode switch. See Installation Considerations on page 6 for more information
about each of the turn-on modes.
Control Output
This terminal provides a 12v DC signal suitable for triggering Niles automated switchers,
some motorized screens, some electric curtain
controls, etc. The trigger voltage is present
only when the amplifier is active or "on".
When the amplifier turns "off", the 12 volt signal is off.
9 Setting The Turn-On Mode Switch
9 Control Output
10 Speaker Wire Connections
13 Line Level Audio Inputs
13 Cascade Audio Outputs
14 AC Power plug
17 Rail Fuse Holders
STEP
1. Check the requirements of the
device you want to control.
2. Connect the 3.5mm Jack to the
control output maintaining proper
polarity (tip = +)
DESCRIPTION
The control output has a maximum
current capability of 12vDC 150 mA.
Niles makes an accessory cable
plug FG00724.
Using the
3.5mm jack.
Slide the switch with your fingernail or a
1/8” slotted screwdriver blade.
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INSTALLATION
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INSTALLATION
Speaker Wire Connections
CAUTION! All speaker wire connections must be made with the amplifier Off.
Bare Wire
Unscrew the red or
black plastic knob,
insert the bare wire
end into the opening,
and then tighten the
knob until the wire is
securely clamped.
Banana Plugs
There are many types
of banana plugs, some
crimp, some solder.
The Niles gold banana
plug has a quick-connect binding post for
the bare wire on the
body of the plug. A
banana plug is simply
inserted into the jack
at the end of the amplifier’s binding post.
Dual banana plugs
will fit the SI-245 binding posts.
STEP
1. Label all wires.
2. Connect one stripped wire end or
banana plug to the black terminal
and one to the red terminal.
CAUTION- Avoid even a single strand
of wire touching the chassis or another
connector .
DESCRIPTION
If you label the wires for their destination,
rather than which terminal of the SI-245 they
are connected to, it will be easier to reconfigure your system in the future.
A. Split the speaker wire insulation so that
at least two inches of each conductor are
separated.
B. Strip one half inch of insulation from the
end of each conductor of the speaker wire
C. Attach banana plugs or twist the strands of
wire together and insert them into the appropriate binding post.
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Line Level Audio Input
CAUTION! THE AMPLIFIER MUST BE OFF WHENEVER YOU MAKE CHANGES
TO THE INPUT CONNECTIONS.
Cascade Audio Outputs
The "Cascade Audio Outputs" enable you to connect another amplifier to your
preamplifier output. The connectors are gold-plated RCA phono jacks. Connect
them to another amplifier’s inputs with a standard audio patch cable. The outputs
are not buffered; if you wish to daisy-chain more than 5 Niles amplifiers you will
need a Niles ADA-6 buffered distribution amplifier. A single ADA-6 will allow
you to daisy-chain 5 amplifiers from each of its six outputs, allowing 30 SI-245
power amplifiers to be fed from the same master preamplifier. If your preamp has
a vacuum tube output stage, you must use a Niles ADA-6 to drive more than a
single SI-245.
STEP
1. Label all of the interconnecting
cables for the sources they connect to.
2. Connect the sources by inserting the
RCA plugs into the amplifier’s jacks.
DESCRIPTION
Use audio patch cables with RCA phono
plugs attached to the ends.
Connect outputs from your sources to
inputs on the amplifier. Never connect a
source or preamplifier’s input (e.g., record
inputs) to the inputs of your SI-245.
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INSTALLATION
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INSTALLATION
AC Power Plug
STEP
Plug the female IEC socket of the supplied AC cord into the IEC receptacle
on the rear of the amplifier.
Plug the 2 prong plug into a correctly
grounded 120V 60 Hz wall outlet.
CAUTION! Typically the
preamp/receiver’s switched outlet is
not rated for a power amplifier.
DESCRIPTION
Just like a computer or printer, the SI-245
has an AC cord which unplugs either at the
amp or at the wall for your convenience.
If you use a grounded power strip, surge
suppressor or extension cord, verify that
proper ground is maintained.
The SI-245 draws a maximum of approximately 200 watts from an AC wall outlet.
Use the auto turn on circuit instead.
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OPERATION
Power Switch
The front panel switch is a master or "vacation" power switch. No matter which
turn-on mode you have selected, the master power switch will turn off all circuitry—including the sensing circuitry. If you will not be using the amplifier for
an extended period of time, turn the master power switch "Off" (push button
switch out). When you would like to return to normal operation, turn the switch
"On" (push button switch in).
Power LED
The power LED indicates that the AC cord is plugged into a working AC power
receptacle and that the power switch is in the "On" position.
Active LED
The rear panel turn-on mode switch determines when and how the amplifier will
turn on. The "Active" LED indicates that the amplifier is operating.
Protection LED
The front panel protection LED indicates that the amplifier has been shut down
because of either a fault in the wiring or a speaker, or with the SI-245 itself.
Level Adjustment Screws
The front panel level adjustment screws allow you to adjust the level of the
SI-245 relative to other amplifiers in your system. Use a 1/8” slotted screwdriver
to adjust the screws. If the SI-245 is the only amplifier in your system, leave the
screws at their factory default position (turned fully clockwise).
Cleaning and Maintenance
The internal parts of the SI-245 are electronic and require no maintenance. Once
a year it is appropriate to twist the RCA connectors on each input to remove corrosion and improve conductivity.
You can clean the amplifier with soft cloth or a paper towel dampened with water
or a mild detergent. Do not use any spray-type, abrasive cleaners on the amplifier.
OPERATION
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TROUBLESHOOTING GUIDE
TROUBLESHOOTING GUIDE
When there is a problem consult this guide first. If the problem persists, or you
have additional questions, call your local Niles dealer or Niles Technical Support
at 1-800-289-4434. The most common problems relate to hook up. Call from
your telephone extension nearest the system.
SYMPTOM
No sound on one channel
No sound on both channels
Hum from the speakers
POSSIBLE CAUSES AND TEST PROCEDURE
Short circuit or loose wire at the speaker or amplifier terminals. Check that the connections are secure
and that there are no loose strands of wire crossing
from the positive to the negative terminals at the
back of the amplifier and/or the speaker.
Short circuit or a break in the speaker wire. Disconnect the speaker wire at both ends, separate the
2 conductors at both ends and test with a meter for
a short circuit. If there is no short, connect the two
conductors at one end and test with a meter for
continuity.
Speaker is not working. Connect the speaker to a
channel that plays another speaker.
Audio cable to input is bad. Connect another cable
that is known to be good.
Audio cable to the main inputs is bad. Connect
another cable that is known to be good.
Hum may be caused by a ground loop between
two of the other components in the system. To test
for another ground loop, try reversing the AC plugs
of each of the components in the system.
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TROUBLESHOOTING GUIDE (continued)
SYMPTOM
Hum from the speakers
Amp will not turn on
Bass sound is weak and
the stereo image is
"phasey" or "blurry"
sounding in one room
POSSIBLE CAUSES AND TEST PROCEDURE
Check for faulty cables, faulty source material, an
ungrounded phono system or a defective component.
AC power cord must be plugged into a working outlet.
Master power switch must be on.
The loudspeakers are wired out of phase. Reverse
the connections at the back of one speaker.
TROUBLESHOOTING GUIDE
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SPECIFICATIONS
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SPECIFICATIONS
Design Principle
Linear voltage/current amplification.
Continuous Average Power Output
45 watts per channel RMS at 8 ohms.
70 watts per channel RMS at 4 ohms.
Input Impedance
22K ohms
Input Sensitivity
.77V for 8Ω rated output
Overall Voltage Gain
28 dB
Frequency Response
Bandwidth Limited from 10 Hz to 100 kHz
Total Harmonic Distortion
8 Ohms
.05% THD from 20 Hz to 20 kHz @ full rated power
4 Ohms
.06% THD from 20 Hz to 20 kHz @ full rated power
Overall Dimensions
17” wide 2-5/16” high (including feet) 13-1/8” deep
Weight
15 lbs
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Niles Audio Corporation
www.nilesaudio.com
12331 S.W. 130 Street
Miami, Florida 33186
Tel: (305) 238-4373
Fax: (305) 238-0185
©1998 Niles Audio Corporation. Because Niles strives to continuously improve its
products, Niles reserves the right to change product specifications without notice.
Niles and the Niles logo are registered trademarks of Niles Audio Corporation.
Systems Integration Amplifier and BusMatrix are trademarks of Niles Audio
Corporation. Printed in the USA 12/98 DS00241A
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