Installation & Operation Guide Systems Integration Amplifier ® B l e n d i n g H i g h F i d e l i t y a n d A r c h i t e c t u r e® ®
Congratulations! Thank you for purchasing the Niles SI-275, one of the most flexible and convenient amplifiers ever offered. Like all Niles products, the SI-275 is built to the highest standards of quality control and reliability. With proper installation and operation, you’ll enjoy years of trouble-free use.
The SI-275 is a member of the award-winning Niles Systems Integration Amplifier family. It is designed for home theaters and whole house audio systems requiring high power. Niles specifically created Systems Integration Amplifiers to solve the problems of interfacing with different brands and models of equipment, different acoustic environments in different rooms, and different kinds of applications: home theater, stereo, and background music.
Features and Benefits Features and Benefits Real World Power The SI-275 delivers 75 watts per channel at 8 ohms and 120 watts per channel at 4 ohms. You’ll get tremendous bass and dynamics from every pair of speakers powered by an SI-275. Transparent Sound The audio circuitry of the SI-275 is constructed using the finest parts available; including 1% metal film resistors, high quality capacitors, and oversized heat sinks.
The SI-275 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-275 to interface with any kind of system and have the unit automatically turn on. Automatic Protection The SI-275 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.
Installation Considerations Installation Considerations Placement Place the SI-275 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 will result in damage to the amplifier’s connectors and controls. The SI-275, like any hi-fi component, will last much longer if it is given adequate ventilation for proper cooling.
The SI-275 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-275 on and off. Installation Considerations Turn-On Modes Constant - The auto turn-on circuitry is off.
Installation Considerations Multiple Speaker Loads The SI-275 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-275. Note that the SI-275 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.
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-275 they are connected to. The SI-275 connects to your sources 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.
Front and Rear Panel Details 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 the speaker, the wiring, or with the SI-275 itself.
Front and Rear Panel Details Level Adjustment screws enable you to preset the maximum system volume (or match levels with another amplifier). NOTE: AC receptacle must be easily accessible. Binding posts for speaker connections. IEC receptacle for AC power cord.
Installation Installation Page 11 Setting the Turn-On Mode Switch Page 13 Line Level Audio Inputs Page 11 Control Output Page 14 AC Power plug Page 13 Cascade Audio Outputs Page 12 Speaker Wire Connections Setting the Turn-On Mode Switch The SI-275 has three turn-on modes. Select which mode you desire by sliding the mode switch. See Installation Considerations on page 6 for more information about each of the turn-on modes. Slide the switch with your fingernail or a 1/8” slotted screwdriver blade.
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.
Installation Line Level Audio Input Caution! The amplifier must be off whenever you make changes to the input connections. STEP DESCRIPTION 1. Label all of the interconnecting cables for the sources they connect to. Use audio patch cables with RCA phono plugs attached to the ends. 2. Connect the sources by inserting the RCA plugs into the amplifier’s jacks. Connect outputs from your sources to inputs on the amplifier. Never connect a source or preamplifier’s input (e.g.
STEP DESCRIPTION Plug the female IEC socket of the supplied AC cord into the IEC receptacle on the rear of the amplifier. Just like a computer or printer, the SI-275 has an AC cord which unplugs either at the amp or at the wall for your convenience. Plug the two-prong plug into a correctly grounded 120V 60 Hz wall outlet. If you use a grounded power strip, surge suppressor or extension cord, verify that proper ground is maintained.
Operation 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).
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 Possible Causes and Test Procedure No sound on one channel Short circuit or loose wire at the speaker or amplifier terminals.
troubleshooting guide TroubleShooting Guide (continued) Symptom Possible Causes and Test Procedure Hum from the speakers Check for faulty cables, faulty source material, an ungrounded phono system or a defective component. Amp will not turn on Bass sound is weak and the stereo image is “phasey” or “blurry” sounding in one room 17 AC power cord must be plugged into a working outlet. Master power switch must be on. The loudspeakers are wired out of phase.
Design Principle Linear voltage/current amplification. Continuous Average Power Output 75 watts per channel RMS at 8 ohms, both channels driven 120 watts per channel RMS at 4 ohms, both channels driven Specifications Specifications Input Impedance Approximately 15K ohms Input Sensitivity .920V for 8 ohm rated power .810V for 4 ohm rated power Overall Voltage Gain 28.5 dB Frequency Response Bandwidth from 10 Hz to 70 kHz (-1 dB) Signal to Noise Ratio > 115 dB, A-weighted Total Harmonic Distortion 8 ohms .
Niles Audio Corporation 12331 S.W. 130 Street Miami, Florida 33186 Tel: (305) 238-4373 Fax: (305) 238-0185 www.nilesaudio.com ©2000-2009 Niles Audio Corporation. Because Niles strives to continuously improve its products, Niles reserves the right to change product specifications without notice. Niles, the Niles logo, Systems Integration Amplifier, and Blending High Fidelity and Architecture are registered trademarks of Niles Audio Corporation. BusMatrix is a trademark of Niles Audio Corporation.
