Features
Controls
Connections
Specifications

Features

Microcontroller Technology: The Niles SI-1260 12-channel amplifier incorporates microcontroller technology which maximizes the amplifier's operational efficiency and enables it to deliver a solid 60 watts per channel into 8-ohms at 20 to 20,000 Hz with a 0.04% THD. Its power increases to 80 watts per channel into 4-ohms at 20 to 20,000 Hz with a 0.06% THD. The massive Multi-Tap Toroid power transformer feature 6 independent secondary windings, one for each of the six amplifier modules. This type of power supply design provides the power necessary to deliver solid, deep, controlled bass response to a house full of speakers.

Twelve to Six channel configurable power: Each of this unit's six adjacent output pairs are bridgeable, allowing you to create up to six 120 watt channels.  This allows you to allocate more power to specific locations such as large rooms or outdoors.

Discrete Output Transistor Design: The audio circuitry of the SI-1260 is constructed with the finest parts available including the latest in discrete output transistor design, featuring 1% metal film resistors, high quality capacitors and oversized heat sinks. All of this attention to technical detail results in a sound that is clear and uncolored.

Protection Modes: The SI-1260 utilizes advanced microcontroller base operation circuitry that monitors all facets of the amplifier's operation and protection modes including 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, CH11/12) as well as for the amplifier's main power supply, providing fast and easy troubleshooting. In the unlikely event that the a problem occurs on one channel pair, the other channels will continue play. When condition return to normal, regular operation will resume.

Dual Input BusMatrix Selector: Nile's unique Dual Input BusMatrix Selector give you the flexibility to individually assign each amplifier channel to a BusMatrix input signal - either Left1, Right1, Left1+Right1, Left2, Right2, Left2+Right2, or to dedicated signal input. With the BusMatrix, routing surround sound to the master bedroom, stereo to the den, and mono to a bathroom is a simple as flicking a switch. The Dual Input BusMatrix makes the SI-1260 an ideal multi-room or MultiZone amplifier, offering the professional installer new features and sound system design possibilities.

Noise Isolation: The unique design of the SI1260's Dual Input BusMatrix PC board ensures extremely high channel-to-channel isolation. Signal-to-noise ratio and cross-talk specifications are comparable to hose of mixing consoles used in professional recording studios. With the SI-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 individually adjust the setting for up to twelve different speaker locations for optimum audio performance, providing uniform sound in every room.

Three turn-on modes: The SI-1260 features three selectable turn-on modes including Audio Sensing and External Voltage Trigger modes which enable you to configure the SI-1260 to turn on automatically in any kind of system configuration.:

• Manual: turns on via the front panel switch
• Audio Sensing: microcontroller enhanced audio sensing which activates only appropriate amplifier channels while leaving unused channel pairs off to eliminate cross talk
• AC/DC Voltage Trigger: 3-30 volt AC/DC voltage trigger input which enables voltage activation

DB25 Audio/Voltage Trigger Inputs: The SI1-1260 incorporates a DB25 input connector to reduce wiring and installation time when using Niles Systems Integration Electronics. Nile Multi-Zone preamplifiers are equipped with a mating DB25 output connector. This output connector provides six zones of line-level audio signal output and a 12V Trigger Voltage for reliable amplifier activation.

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 so to daisy chain more than five Niles amplifiers you will an optional Niles AVDA-3 buffered distribution amplifier, sold separately. A single AVDA-3 enables you to daisy chain five amplifiers for each of its three outputs. This allows fifteen SI-1260 power amplifiers to be fed from the same master preamplifier. If your preamplifier has a vacuum tube output stage, you must us an optional Niles AVDA-3 to drive more than one SI-1260.

Placement: The SI-1260 should be placed on a flat, level surface like a table or shelf. The SI-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. The manual recommends at least 6" of free air space above the chassis and 1" on each side of the amplifier for proper ventilation. If the unit is placed inside a cabinet the rear of the cabinet should be opened. If the rear of the cabinet is closed and not open to fresh air then you should install two "boxer fans" to provide continuous air flow into and out of the cabinet to keep the amplifier cool during operation.

Controls

Front panel:

• Master power switch: Turns the unit on and off, including the auto turn circuitry.
• Power LED: Illuminates in red when the unit is connected to AC and the master power switch is on. Additionally, it indicates any AC line voltage problems and main power fuse status.
• Channel LEDs: Six Multi-color LED indicators which display channel pair on/off status and protection modes.

• Turn-on mode switch: Allows you to select one of three modes.  Constant mode defeats the turn-on circuitry and the front panel master power switch turns the unit on and off.  Audio sense mode turns the amplifier off when no audio signal is present for two minutes and on whenever an audio signal is present (it turns on the adjacent pair of amplifier channels that have a signal present, such as 1 and 2 .  3-30 volt AC/DC Trigger mode turns the unit off when no AC or DC voltage is detected at the trigger input and turns on all adjacent channel pairs when a voltage and a line level audio signal is detected at an adjacent channel pair.  
• Independent level adjustment rotary knobs: Allow you to preset the maximum system volume or match levels with another amplifier for each of the twelve channels.
• Bridge switches: Six switches allow you to bridge adjacent amplifier channels to create up to 6 bridged channels.  Note that minimum speaker impedance in bridged mode is 8 ohms.
• BusMatrix control switches: 12 7-pin DIP switches (one per channel) allows you to assign a particular source to each channel.  You can select the signal from the main Bus input and select either Left, Right or Mono (left and right) or you can select the signal going to that channel's dedicated input.  Note that only one signal source should be selected per channel.

Connections

3-30V AC/DC trigger input: 3.5mm female jack for voltage input.  If a unit which outputs 3-30V AC or DC voltage is connected to this input and the turn-on mode is set to Trigger mode the unit turns on when it detects the signal and turns off when the signal stops.  Voltage triggers are supplied by some Niles automated switchers, some video projectors or even a 16 volt Niles AC wall adapter (Niles XF00008).

12 volt control output: Female 3.5mm jack.  This jack provides a 12V DC signal used for triggering Niles automated switchers, some motorized screens, curtains, etc.  When the amplifier is turn off this jack stops sending out the 12V DC signal. 

Main Bus inputs: Two pair of Gold plated RCA stereo inputs. This signal can be routed to any of the twelve channels using the DIP switch found on each channel.

Cascade Bus Output: Two pair of Gold plated RCA stereo outputs (marked Cascade output) which allow you to daisy chain multiple amplifiers.  This output is not buffered so if you want to chain more than 5 amplifiers a buffered distribution amplifier like the Niles AVDA-3 is needed.

Individual input jacks: 12 gold-plated RCA jacks, one per channel.

Speaker outputs: Left and Right Binding posts for 12 channels (not five-way due to spacing) accept up to 12 gauge bare wire or banana plugs.

DB-25 Input: DB-25 input connector for simplified dedicated audio and voltage trigger connection using Niles Multi-Zone audio equipment

AC jack: For the supplied AC line cord.

Specifications

Continuous Power Output (FTC Rated): 60 watts x 12-channel at 8-ohms or 80 watts x 12-channel at 4-ohms (unbridged, all channels driven).

Bridged Power Output: 120 watts x 6-channel at 8-ohms (adjacent channels bridged, all channels driven)

Input Impedance: 47k ohms

Input sensitivity: .77Volts for 8-ohms at rated output

Overall voltage gain: 32 dB

Frequency response: Bandwidth limited from 5 Hz to 50 kHz

Total Harmonic Distortion:

Weight: 73 lbs.