SI275

About the SI275

The Niles SI-275 is a high-current stereo power amplifier designed for home theaters and whole house audio systems requiring robust power and flexibility. It delivers 75 watts RMS per channel into 8 ohms and 100 watts RMS per channel into 4 ohms, making it ideal for driving multiple speakers including outdoor setups. The amplifier features a discrete, high-current design with independent power supplies for each channel to reduce crosstalk and ensure clear, uncolored sound with excellent imaging. It is stable into low impedance loads (down to 2.67 ohms), allowing safe connection of multiple 8-ohm speakers in parallel. The SI-275 includes three turn-on modes (music sensing, voltage trigger, and manual), independent level controls for each channel, gold-plated inputs and binding posts, and comprehensive protection circuits against DC, short circuits, and overloads. Its large heatsink allows fanless operation, maintaining cool temperatures even under heavy use. The amplifier measures 17"W x 2-5/16"H x 13"D and weighs approximately 21 pounds. It is well-suited for custom integration environments where reliability and sound quality are critical. The SI-275 is discontinued but remains popular on the used market for its solid build and performance.