Niles SI-1260 Original operating instructions

INSTALLATION & OPERATION GUIDE
-
Systems Integration Amplifier®
B lEN 0 I N G HI G H F IDE liT Y AND ARC HIT E C T U R E®

•
CONGRATULATIONS!
Thank you for purchasing the Niles 51-1260 Systems Integration Amplifier, one of the
most versatile and powerful multi-channel amplifiers ever offered. Like all Niles
products, the
51-1260 is built to the highest standards of quality 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 compo-
nents and accessories for audio/video
systems. For afree full-line catalog write:
Niles, Catalog
Request, P.O. Box 160818, Miami, Florida 33116-0818 or visit
www.nilesaudio.com.
TABLE OF CONTENTS
INTRODUCTION
2
FEATURES AND BENEFITS
3
SYSTEM DESIGN BASICS
5
SYSTEM DESIGN CONSIDERATIONS 6
APPLICATIONS 8
CONFIGURING YOUR SYSTEM
13
INSTALLATION CONSIDERATIONS
14
FRONT & REAR PANEL DETAILS
15
INSTALLATION 18
OPERATION
23
TROUBLESHOOTING GUIDE
27
CONFIGURATION WORKSHEET 29
SPECI FICATIONS 30

INTRODUCTION
Designed for use in high-endlhigh-powered distributed audio systems, the St-1260
Systems Integration Amplifier provides a level of performance, flexibility, and ease of
installation previously unavailable to custom installers. The 51·1260'5 unique design
enables each of its channels to be independently configured to reproduce stereo or
mono in any combination, as well as to compensate for differing volume levels in
rooms of different sizes. Additionally, the amplifier's Dual Bus Matrix'" feature and
mulliple inputs enable it 10 be used in several different applications simultaneously
if desired (j.e. mono background music in some rooms and stereo in others).
As you read this manual and become morc familiar with the 51-1260's capabilities,
you will understand why our multi·channel amplifier design has won many presti-
gious induslry awards. The first multi
4
channel amplifier introduced by iles. the
51-1200, was selected Best New Product in 1994 by both Sound & Video Contractor
Magazine and the Custom Electronic Design and lristallation Association (CEDIA). In
addition, the St-1200 also won the Consumer Electronics Show's tnnovations '95
Design and Engineering Award.
51-1260
Systems Integration Amplifier
Figure 1

II
FEATURES AND BENEFITS
Microcontroller Based Real World Power
The 51-1260 12 channel amplifier incorporates microcontroller technology which
maximizes the amplifier's operational efficiency and enables it to deliver asolid 60
watts per chan:;el into 8ohms, 20Hz to 20kHz, 0.04% THO.
Its power increases to
80 watts per channel into 4ohms,
20Hz to 20kHz, at 0.06% THO. The massive
Multi-TapToroid power transformer features 6independent secondary windings, one
for each
of the six amplifier modules. This extraordinary power supply design pro-
vides the power necessary to deliver solid, deep, controlled
bass response to ahouse
full
of speakers.
Transparent Sound
The audio circuitry of the 51-1260 is constructed with the finest parts available includ-
ing the latest in discrete output transistor design, featuring 1% metal film resistors,
high quality capacitors and oversized heat sinks. All this attention to technical detail
results in asound that
is clear and uncolored.
Microcontroller Based Operation and Protection Modes
The 51-1260 utilizes advanced microcontroller based operation circuitry that
monitors all facets
of the amplifier's operation and protection modes: over/under line
voltage, main power
fuse status, channel pair on/off status, thermal protection, short
circuit/low impedance protection and DC output protection. Additionally,
easy to
see front panel LED indicators display the operation or protection mode for each
channel pair (CH1/2, CH3/4, CH5/6, CH7/8, CH9/10 and CH
11 /12) as well as for
the amplifier's main power supply, providing
fast and easy troubleshooting. In the
unlikely event that aproblem occurs on one channel pair, the other channels
will
continue to play. When conditions return to normal, regular operation will resume.
Dual Input BusMatrix™ Selector
Nile's unique Dual Input BusMatrix'" selector gives you the flexibility to individually
assign each amplifier channel to aBusMatrix'" input signal, either Leftl, Rightl,
Leftl +Rightl, Left2, Right2,
Left 2+Right2, or to adedicated signal input. With the
BusMatrix'", routing surround sound to the master bedroom,
stereo to the den, and
mono to abathroom
is as simple as flicking aswitch. The Dual Input BusMatrix'"
makes the
51-1260 an ideal multi-room or MultiZone amplifier, offering the profes-
sional installer exciting new features and sound system design possibilities.

Twelve to Six Channel Configurable Power
Each of the 51-1260's six adjacent output pairs are bridgeable. You can create up to
six 120-watt channels
by setting the bridging switch to the "BRIDGED" position.
These switches are located at the top of the rear panel (see Page 27 figure 16).
Bridging enables you to double the power to specific speaker locations, including
large rooms and outdoor applications.
Freedom from Noise and Cross-Talk
The unique design of the 51-1260's Dual Input BusMatrix'M PC board ensures
extremely high channel-to-channel isolation. 5ignal-to-noise ratio and cross-talk
specifications are comparable to those
of mixing consoles used in professional
recording studios. With the 51-1260, the music playing in the living room
will not
interfere with the music playing in the den.
Independent Level Controls
Each channel has its own independent volume level control, enabling you to indi-
vidually adjust the setting for up to twelve different speaker locations for
optimum
audio performance, providing uniform sound in every room.
Turn-On Modes
The 51-1260 features three selectable turn-on modes: (7) manual turn-on via the front
panel switch, (2) microcontroller enhanced audio
sensing which activates only the
appropriate amplifier channels while leaving
unused channel pairs off to eliminate
cross talk and (3) a3-30 volt AC/OC voltage trigger input which enables voltage acti-
vation. Audio
5ense and External Voltage trigger modes enable you to configure the
51-1260 to turn on automatically in any kind of system configuration.
0825 Audio and Voltage Trigger inputs
The 51-1260 incorporates a.OB25 input connector to reduce wiring and installation
time when using Niles Systems Integration Electronics. Niles MultiZone
preamplifiers are equipped with amating OB25 output connector. This output
connector provides 6zones
of line-level audio signal output and a12V Trigger
Voltage for reliable amplifier activation.
Designed in the USA
The Niles 51-1260 was designed in the USA by Niles engineers and includes a two
year parts and labor warranty.
II

FAMILY ROOM LIVING ROOM
LISTENING ZONE 1
SYSTEM DESIGN BASICS
[J
= =
ASingle-Zone System
allows only one source to
be heard throughout the
house at agiven time.
Figure 2 - Single Zone System
As shown in Figure 2, adistrib- ..------.",
uted audio/video system is "-----.;:,-....
defined by the number
of listen-
ing zones it
has. Within alis-
tening zone you
can listen to
only one source (e.g. COl
Radiol Tape, etc.) at anyone
time. Alistening zone can con-
sist of asingle room or agroup
of rooms. To achieve different
volumes and greater conve-
nience in different rooms with-
in azone, individual volume
controls can be used. Niles
makes volume controls in vari-
ous
styles and colors. When
designing your system, take
into account who
will use the
system and when they will use
it. Consult your local Niles
dealer for more information.
r--
r --
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IFAMILY
ROOM I
ILISTENING ZONE 2 II
L...- _
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ILIVING ROOM I
I
ILISTENING ZONE 1I
L...- _
AMultiZone system as shown
in Figure
3, offers the house-
hold more flexibility. For
instance, afamily might have
their family room wired for sur-
round sound and their living
room wired for background
music.
In atwo zone system,
the children can watch TV in
surround sound
while Mom
and Dad are reading the paper
and enjoying background
music in the living room.
Figure 3 - MultiZone System
II

SYSTEM DESIGN CONSIDERATIONS
Speaker Compatibility
Asingle channel (not bridged) of the 51-1260 is capable of driving a low impedance
speaker load.
As many as three 8ohm speakers can be safely connected to asingle
channel, presenting the amplifier a2.66 ohm load. Proper ventilation
of the 51-1260
is critical when driving low impedance loads. If the 51-1260 is not properly
ventilated, the protection circuits may activate and shut off the channel at higher
volume levels (for more information on proper amplifier placement,
see Installation
Considerations on page 77).
Achannel pair that has been BRIDGED is capable of driving an impedance load of
4ohms. Proper ventilation of the 51-1260 is critical when driving a 4 ohm load with
bridged channels. Ifthe 51-1260 is not properly ventilated, the protection circuits may
activate and shut off the channel at higher volume levels (for more information on
proper amplifier placement,
see Installation Considerations on page 77).
When designing your system, try to specify 6-8 ohm speakers (Niles offers acom-
plete line
of in-wall, in-ceiling, outdoor and home theater loudspeakers with allmod-
els rated from 6-8 ohms).
Cable and Wire
Because the 51-1260 has many connections on the rear panel (see Figure 13), it is
important that you correctly label all of the input cables and speaker wires. Label the
cables and wires
with their destination or source, rather than the 51-1260 terminal to
which they are connected. This
will make it easier to reconfigure your system in the
future.
The 51-1260 connects to your sources via shielded line level audio cables with RCA
connectors. 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.
AOB25 MultiZone Input Connector
is provided for use with Niles MultiZone
Products which include amating OB25 output connector. All 12 dedicated inputs
are included within the single connector, along
with the 51-1260's Voltage Trigger
Input.
The
51-1260 connects to your speakers using two conductor speaker wire. For most
applications,
we recommend you use 16 or 18 gauge wire. For wiring n ns longer
than 80 feet, we recommend
14 gauge wire. The 51-1260's high-quality, gold-plated
5-way binding posts
will accommodate up to 12-gauge wire. Attaching banana plugs
to the wire
will enable the connection of larger wire sizes.
•

•
Using Mono for Smoother Coverage
In large or irregularly shaped rooms, you may find that the main listening area may
be closer to one
of the speakers. Ifthe speakers in the room are connected to astereo
amplifier you
will only hear halfthe music. The 51-1260's BusMatrix'" enables you to
create
mono sound from one speaker without impacting the stereo quality in the rest
of the system. You can configure each room to either stereo or mono as needed with
no ill effects. Some
of the most popular areas where mono will greatly enhance the
sound quality
would be:
•
Large rooms with many seating areas and/or many pairs of speakers.
•Irregularly shaped rooms.
•Bathrooms with one speaker over the tub and one speaker over the sink(s).
•Hallways or passageways (including those with multiple speakers).
•Small rooms, such as walk-in closets where more than asingle speaker is not
required.
Bridging Channels for Areas that Require More
Volume and Power
There are several situations where bridging is an excellent way to improve the sound.
There are also applications where bridging
would seem to be appropriate but is not
recommended. Bridging channels increases the power to 120 watts per channel with
an 8ohm impedance.
These are some of the most common DOs and DON'Ts:
1. Outdoors (DO) -Sound dissipates faster outside than it does in aroom where
the walls enclose the sound and reflect it back to the listener. Apair
of speakers
playing into alarge patio or yard
will greatly benefit from bridging four channels
into
two 120 watt channels.
2. Surround Sound Systems (DO) - The dynamic demands for the center channel
are much greater than the left, right or surround channels. This
is an excellent
application for
two channels to be bridged into one 120 watt channel.
3. More than one pair of 8 ohm speakers (DON'T) -In alarge room or along hall-
way, often the best way to get good background music is to install multiple pairs
of speakers. You will actually deliver more power to two pairs of 8ohm speakers
by using
two unbridged amplifier channels than you would if you bridged four
amplifier channels into
two and connected the two pairs of speakers in parallel.

APPLICATIONS
Advantages of Using the 51-1260 in aSingle Zone System
By connecting aNiles 51-1260 to astereo receiver's preamplifier outputs, you dedi-
cate arobust 60 watts to each speaker in your multi-room system.
Each channel has
its own level control, enabling you to compensate for architectural differences which
may cause one speaker to seem louder than another. In addition, you can fine tune
the
system so that when all of the room volume controls are set to the loudest level,
the large rooms and the small rooms play at the same volume.
DSS
Niles VCS-2D
Volume Control
VCR
Preamplifier or
AM/FM receiver
SI-1260
0- 'YYYT Tt,
CD
Room 1Room 2Room 3Room 4
RoomS
Room 6
Single Zone
Figure 4 - Single Zone
II

IRC-2
(Fixed)
(Variable)
tw"
81-1260
0-
~~:::::=~~t- BusMatrix'" Input 2
BusMatrix'" Input
1----......
Niles VCS-2D
Volume Control
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Creating aLow-Cost Second Zone
Using aDedicated Source
The main problem in asingle zone system is that when asource is being listened to
in one room, you cannot listen to another source in another room simultaneously.
However, for alistener
who only listens to CDs, alow-cost second zone may be cre-
ated to
allow simultaneous CD listening while the main system is playing another
source. This
is possible only if the CD player you are using has dual audio outputs,
one with remote controllable volume and the other afixed volume.
As shown in
Figure 5, you connect the CD player's variable output to the 51-1260's dedicated
channel inputs for the particular room where you
will listen only to CDs. The fixed
output
is connected to the main preamp or receiver so you can also listen to CDs in
the
rest of the house. The finishing touch is to install aNiles infrared repeater system
(lRR-40, IRP-2+ and IRC-2) so you may adjust the CD player's volume via remote
control from your CD listening room.
ZONE 1ZONE 2
Figure 5 - low Cost Second Zone for CDs
I

Using aDual-Zone Receiver for Two Listening Zones
Most of today's Dolby Digital surround sound receivers include asecond zone pre-
amplifier output
used to create asecond listening zone. Using this output with one
of the 51-1260's BusMatrix™ inputs provides amplification for multiple rooms within
asecond listening zone
as shown in Figure 6.
DVD/CD
CHANGER VCR
DSS
---- Second Zone Output
I
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ZONE 1I
(Home Theater) :
I I
:_ ~r~n~ ~~e~k~~ __ S;~n!e~ ~p_e~k~r R~~ ~e.e~':e~s _ ~
BusMatrix'" Input 1 ~r----------_----1
Niles VCS-2D HP
Volume Control
(HP =High Power)
SI-1260
0-- .. "" ..
Niles VCS-2D
Volume Control
I
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Living Room Kitchen Exercise Room Hallway Patio I
I(Unbridged Channels1-8) (Bridged Channels :
L ~~J~~l_~
Figure 6 - Using aDual Zone Receiver

ZONE 6
DVD/CD
CHANGER
ZONES
•
ZONE 4
AM/FM
TUNER
81-1260
0- """"
ZONE 3
ZONE2
DSS
ZONE 1
-------- -------- ---~~--- -------- --------
II
II
II
II
II
II
II
II
I II II III
--------~--------~--------~--------~--------~--------~
Adding Preamps To Create More Listening Zones
In the ultimate MultiZone system, you would connect six stereo preamplifiers (or a
single component multi-zone/multi-source preamplifier) to one 51-1260, creating six
completely independent listening
zones. MultiZone systems enable listeners located
in six separate zones to simultaneously listen to different source components as
shown in Figure 7.
Figure 7 - Creating More Listening Zones
III

ZONE 3
... -------,
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ZONE 4
... -------,
I I
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I..J
ZONE 5
... -------,
I I
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1
--'
ZONE 6
,..-------,
I
•
81-1260
Zones 3-6
CJ -
•
..,-----BusMatrix'· Input 2
81-1260
AM/FM
TUNER
CJ -
Niles A4.6Ci ..
Zones 1-2/
BusMatrix'· Input 1 -----....-
Niles VCS·2D
Volume Control
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-----'==--=::::1..- I
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ROOM 1 ROOM 2 ROOM 3 ROOM 4ROOM 5 ROOM 6I
________________________ JI J
ZONE 1ZONE 2
Many MultiZone systems incorporate multiple rooms within asingle zone. The
51-1260's Dual
BusMatrix™ Input simplifies the connections required for this sys-
tem design. As shown in Figure 8, aNiles A4.6Ci MultiZone Controller has its first
and second zone outputs connected to the 51-1260's Dual
BusMatrix™ #1 and #2
inputs respectively. Bus Input #1 is then routed to amplifier channels one through
six via
dip switch settings. Bus Input #2 is routed to amplifier channels seven
through twelve in the
same manner. 5ix rooms can now be connected to the 51-
1260 placing three rooms in Zone #1 and three rooms in Zone #2. The remain-
ing zone outputs on the A4.6Ci can be connected to another 51-1260 for more
zones.
Utilizing the Dual BusMatrix™ Input
Figure 8 - Dual BusMatrix'· Input

CONFIGURING YOUR SYSTEM
The 51-1260 offers many configuration possibilities. Therefore, carefully plan the
installation before starting. Start by drawing ablock diagram
of your system and use
the Configuration Worksheet on page 29 to document how you plan to connect your
51-1260. Figure 9, shown below, is an example of aConfiguration Worksheet filled
out according to the block diagram (figure
6) on page 70.
Figure 9
Sample Configuration Worksheet
BUS INPUTS &OUTPUTS CONNECTED TO ...
Left Bus Input #1Second Zone Left Output
Right Bus Input #1Second Zone
Right Output
Left Bus Input #2 N/S
Right Bus Input #2 N/S
Cascade Output Bus #1Right N/S
Cascade Output Bus #1Left
N/S
Cascade Output Bus #2Right N/S
Cascade Output Bus #2Left
N/S
CH #BRIDGED DIP INPUT SOURCE SPEAKER
1D
L1
Bus #1
Left Living Room
2 R1
Bus #1
Right Living Room
3D
L1
Bus #1 Left Kitchen
4 R1
Bus #1
Right Kitchen
5DL 1 Bus #1 Left Exercise Room
-----_.
6 R1
Bus #1
Right Exercise Room
7D
L1+R1 Bus #1
Hallway #1
--
8
L1+Rl
Bus #1
Hallway #2
9
~
Off N/S N/S
1---
--- --
10
L1
Bus #1 Left Patio
11
r;I
Off
N/S N/S
12 R1
Bus #1
Right Patio
MODE SETIINGS IN USE SPECIAL CONNECTIONS OR NOTES
Constant D
Audio Sense ri/
Voltage Trigger D
Control Output D

INSTALLATION CONSIDERATIONS
Important! The Front Panel Power 5witch must be in the ON (switch in) position for
any
of the three turn-on options to function (refer to page 23 for more information
concerning the Front Panel Power Switch). TURN
ON
MODE
§E
CONSTANT
D AUDIO SENSE
3-30V AC/DC
-TRIGGER INPUT
Figure 10 -Turn-On Mode
Turn-On Modes
Automating the turn-on of your 51-1260 is one of the easiest steps when installing it
in adistributed
system. However, do not plug the main power cord into the switched
AC outlet of your preamplifier or receiver. The high power design of the 51-1260
requires large amounts of current from its AC power source. Additionally, it is always
recommended to activate the
system preamplifier/receiver before turning on your
51-1260 in order to prevent system "turn-on thumps". In order to address these
important needs, the 51-1260 has three special turn-on modes that let you turn the
amplifier on only when it
is needed. These three options are accessed by the Turn-
On Mode selector switch (see Figure 10).
Constant:
The auto turn-on circuitry is "OFF".
The front panel master power switch operates
the amplifier. When the switch
is in, the amp
is "ON", when it is out, the amp is "OFF".
Audio
Sense: The amplifier is "OFF" when
there
is no audio signal present at any of the
16 inputs, but the sensing circuitry
is active.
The turn-on sensing circuitry looks for atiny
amount of audio signal present at any
of the
audio inputs. If itdetects asignal, the adjacent
pair
of amplifier channels (i.e. channel 7/2,
3/4,5/6, etc.) assigned to receive the input signals will switch "ON". Oncethe audio
signal
stops, the sensing circuit waits approximately 2-minutes, then switches all
amplifier channels "OFF".
3-30V AC/DC Trigger Input: The amplifier is "OFF" when a 3 to 30-Volt AC or DC
signal
is not applied to the voltage trigger input. Once the sensing circuitry detects
such avoltage, all adjacent pairs
of amplifier channels that are receiving an audio
signal switch
"ON". Once the voltage is removed, the Voltage Trigger circuit instant-
ly switches the amplifier "OFF". Voltage triggers
may be supplied by Niles automat-
ed switchers, some video projectors, some surround sound processors, or a 12 Volt
DC wall adapter (Niles FCD0665) plugged into the switched outlet
of your stereo
receiver.
If you
are using awall 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 aminimum of 38 milliamps for a3D-Volt trigger).
continued on page 1 7.

Attractive extruded
aluminum front panel.
Multi-color "Channel Pair"
LED indicators
display channel pair on/off status,
and protection modes
/
51-1260 5Y5TEMS INTEGRAl N AMPLIfIER
//
.
~
~
~
(C'~'"
CI-IANNHS
U""NNHS
n'ANNrlS O ... N"[lS
CH,o.NNHS
~I"OWUl
= = = = =
.-, ,-.
,.
.-.
':l·10 11·12
-
NILES
Red "Power" LED confirms the amplifier is connected to alive AC
outlet and that the front panel switch is on. Additionally, it indicates
any AC line voltage problems and main power fuse status
Figure
13
Front panel "Master Power"
switch turns off the entire
amplifier, including the auto
turn on circuitry.
Removable Two-prong
IEC compatible
AC power cord.
Gold-plated RCA jacks for
the dedicated inputs.
DB-25 input connector for simplified
dedicated audio and voltage trigger
connection using Niles MultiZone Products.
L----'"'~-#------ Serial Number.
Bridging switch for each channel
pair.
Level controls for each
channel.
BusMatrix··controls for each
channel.
"Turn-On" Mode Switch.
----tt-~'r
Cascade outputs of the
bus input enable you to daisy
chain multiple amplifiers.
3.5
mm Jack for
3-30V AC/DC trigger input.
Gold Plated Dual Bus
Inputs, selectable
by the
BusMatrix··, provide
enhanced input flexibility.
3.5 mm
Jack for
12v DC Control Output.
(150 mA max)
Gold plated, dual banana plug
spaced, five-way speaker
binding posts.

continued from page 14.
Placement
A
CAUTION I Placing the 51-1260's weight on the rear or front panels will cause
damage to the amplifier's connectors or controls.
CAUTION! 00 NOT block the ventilation holes on the top and bottom of the
51-1260.
Place the 51-1260 on aflat, level surface like atable or shelf. The 51-1260 must be
placed with its weight equally distributed on the unit's four feet. This amplifier, like any
high-fidelity component,
will last much longer if it is given adequate ventilation for
proper cooling. When installing the
51-1260 in acabinet, be sure that the cabinet's
rear is open to fresh air (see Figure 11). Additionally, place the 51-1260 so that there
are
at least 6inches of free air space above the amplifier and 1inch on each side. If
the amplifier
is located on acarpeted surface, place aboard under the amplifier's feet.
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 12).
CAUTION! When using low impedance speaker loads (less than 4 ohms Normal
Mode, less than 8 ohms Bridged Mode), refer to Figure 12 for proper placement.
A
A
A
The 51-1260 is equipped with amassive toroidal power transformer. This transformer
generates apowerful magnetic field that could induce ahum in aturntable (particu-
larlya turntable
equipped with amoving coil cartridge). DO NOT place aturntable
directly above
or directly adjacent to the 51-1260.
CAUTION! Before placing the 51-1260 on a shelf, verify that the weight bearing
capacity of the shelf is 70 Ibs or greater.
Figure 11
Figure 12
Boxer Fan (105 CFM)
directly centered
6"
on top of the 51-1260.
Boxer
Fan (105 CFM)
directly centered
2"
behind the 51-1260.
Make sure that there is aminimum
of
6" offree air space above the
amplifier and
1" on each side for
proper ventilation.
;!Y&Ii!Y&li~
•
I I .
~
, !
Allow a minimum of 2" of depth
behind the unit to accommodate
cables and connectors.
••
If the cabinet rear is not open to fresh
air or
if your using low impedance
loads, install
two "boxer fans" to pro-
vide continuous air
flow into and out
of the cabinet.

STEP DESCRIPTION
INSTALLATION
Line Level Audio Inputs
A
Cautio~! The amplifier must be off whenever you make changes to the input
connections.
Use audio patch cables terminated with
RCA connectors.
1. Correctly label the interconnecting
cables
coming from each source.
2.
Connect the sources by inserting the
RCA connectors into aBusMatrix™
input or dedicated input jack on the
51-1260's rear panel.
NOTE: When you are using two
amplifierchannels in the "bridged"
mode, assign the audio signal to
be
amplified to the EVEN numbered
amplifierchannel using the
BusMatrix™
Dip Switches.
Connect outputs from your source compo-
nents to the input jacks on the amplifier.
NEVER connect apreamplifier or source
input (e.g., record inputs) to the
51-1260
inputs.
Cascade Audio Outputs
The "Cascade Audio Outputs" enable you to connect additional amplifiers to your
preamplifier's output. Connection is accomplished with standard RCA interconnect
cables. The outputs
are not buffered; to daisy chain more than five Niles amplifiers
you will need aNiles AVDA-3 buffered distribution amplifier. Asingle AVDA-3
enables you to daisy chain five amplifiers from each
of three outputs. This allows 15
51-1260 power amplifiers to be fed from the same master preamplifier. If your pre-
amplifier has avacuum tube output stage, you must use aNiles AVDA-3 to drive
more than one
51-1260.
AC Power Plug
STEP DESCRIPTION
1. Plug
the 51-1260's attached 2prong
power cord into a correctly grounded
120 Volt, 50-Hz wall outlet.
If you use agrounded power strip, surge
protector,
or extension cord, verify that the
proper ground
is maintained
ACAUTION! DO NOT PLUG THE
51-1260'S POWER CORD INTO A
PREAMPLIFIER'S CONVENIENCE
OUTLET.
1. The 51-1260 draws amaximum of about
890 watts from
an AC wall outlet. This is
much more than the typical accessory
outlet on acomponent's rear panel can
provide.
2.
Use the 51-1260's auto turn-on circuitry
to switch
"ON" the 51-1260 when the
preamplifier
is "ON".

Speaker Wire Connections
ACAUTION! All speaker wire connections must be made with the amplifier OFF.
Figure 14 - Binding Posts
~~~ __ ------:::7 Banana Plugs
There are many types of
banana plugs available.
Some
are crimped onto
the speaker wire and
some
are soldered. Niles
offers banana plugs that
have aquick-connect
binding system for the
speaker wire included
within the banana plug
itself. After the wire is
attached, the banana plug
is simply inserted into the
hole at the end of the
amplifier's speaker bind-
ing post. Dual banana
plugs will fit the SI-1260
binding posts.
Bare Wire
Unscrew the red or black plastic
knobs and insert the bare wire
through the hole
in the post.
Tighten the knob until the wire is
securely clamped.
STEP
1. Label all wires.
2. Connect one stripped wire end or
banana plug to the black tenninal
and one
to the red tenninal.
If
all wires connecting to the 51-1260 are
labeled with their destination rather than
their specific connection to the 51-1260, it
will
be easier to reconfigure the system in
the future.
A. Split the speaker wire insulation at least
2 inches.
ACAUTION! NOT EVEN ASINGLE
STRAND OF WIRE CAN BE
ALLOWED TO TOUCH THE
AMPLIFIER CHASSIS OR
ANOTHER CONNECTOR.
B. Strip 1/2 inch of insulation from each
speaker wire conductor.
C. Attach banana plugs or twist the wire
strands of each conductor and insert them
into the appropriate 51-1260 binding post.

BusMatrix
Ti
' Input DIP Switch Settings
Each channel has a dedicated BusMatrix'· DIP switch bank that assigns that chan-
nel's source
input signal (see Figure 15). To assign the BusMatrixmsource input sig-
nal for a particular channel, set only one of the seven switches to the right.
DIP Switch Settings
1L is for the assignment of the Left Bus Input 1t1
1R is for the assignment of Right Bus Input Itl
1L+1R is for the assignment of asummed mono signal of the Left and Right Bus Input #1
2L is for the Left Bus Input 1t2
2R is for the Right Bus Input 1t2
2L+2R is for asummed mono signal of the Left and Right Bus Input 1t2
The seventh switch assigns the dedicated input to its respective channel
Again, only one of the seven DIP switches
should be configured to the liON" position
(switched to the right).
"OFF"Position
I
B
U
s
L
"ON" Position
lL
lR
1 L+ 1R
2L
2R
2L+2R
1
Figure 15 -BusMatrix'· DIP Switches
STEP DESCRIPTION
1. Move only one (1) DIP switch to the
"ON" position for each channel. ACAUTION! EACH DIP SWITCH
ALLOWS YOU TO MOVE
ALL
SEVEN SLIDE SWITCHES TO
THE
"ON" POSITION. IF YOU
SET MORE THAN ONE SLIDE
SWITCH TO
"ON" YOU MAY
CREATE AN UNDESIRABLE
MIX OF INPUTS ON THE
ENTIRE BUS.