I N S T A L L A T I O N & O P E R A T I O N G U I D E Systems Integration Ampliﬁer ® ® ® L E N D I N G I G H I D E L I T Y A N D...
CONGRATULATIONS! Thank you for purchasing the Niles SI-275, one of the most flexible and conve- nient 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.
INTRODUCTION 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;...
FEATURES AND BENEFITS Real World Power The SI-275 delivers 75 watts per channel at 8 Ohms and 100 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;...
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.
(see Figure 2). Place the SI-275 so that there is at least 7" of free air space above the chassis. If the ampli- fier 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-275.
Turn-On Modes The SI-275 draws more current than a preamplifier’s switched AC outlet can safe- ly 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.
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.
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 low- est possible noise and best overall performance.
Front panel “Master Power” switch turns off the entire amplifier, including the Turn-On circuitry. Main Inputs enable you to route a stereo line level source to the SI-275. “ Turn-On Mode 3.5 Mini Plug socket for voltage input.
Level Adjustment screws enable you to preset the maximum system volume (or match levels with another amplifier). Binding posts for speaker connections. NOTE: AC receptacle must be easily accessible. IEC receptacle for AC power cord.
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.
DESCRIPTION If you label the wires for their destination, rather than which terminal of the SI-275 they are connected to, it will be easier to recon- figure your system in the future. A. Split the speaker wire insulation so that at least two inches of each conductor are separated.
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-275 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-275.
DESCRIPTION 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. If you use a grounded power strip, surge suppressor or extension cord, verify that proper ground is maintained.
Protection LED The front panel protection LED indicates that the amplifier has been shut down because of either a fault in the wiring or the speaker, or with the SI-275 itself. Level Adjustment Screws The front panel level adjustment screws allow you to adjust the level of the SI-275 relative to other amplifiers in your system.
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.
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.
SPECIFICATIONS Design Principle Linear voltage/current amplification. Continuous Average Power Output 75 watts per channel RMS at 8 ohms. 100 watts per channel RMS at 4 ohms. Input Impedance Approximately 15K ohms Input Sensitivity .985V for 8Ω rated output Overall Voltage Gain 30 dB Frequency Response Bandwidth Limited from 10 Hz to 100 kHz...