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Niles SI-2150

Stereo power amplifier

7 Reviews | 2 questions - 6 answers


Our take on the Niles SI-2150

The choice of pros since 1978

When professional installers need versatile and rugged components they can depend on, they turn to Niles. Niles' Systems Integration Amplifiers® are powerful tools that simplify and optimize complex custom multi-room installations. While traditional receivers and amplifiers work well in typical stereo and home theater systems, multi-room systems require an amplifier that does more than just drive speakers — these systems require an approach that offers greater flexibility and performance.

Power and performance to spare

Whether you're using the Niles SI-2150 as a part of a multi-room audio system or as the amplifier in your main listening room, you'll find that it delivers plenty of pristine, dynamic stereo power. Its high-current design allows it to handle unusual and reactive loads with ease, including the ability to safely drive up to three pairs of directly connected 8-ohm speakers at the same time. And it's not just all muscle. Niles uses high-quality parts throughout to ensure that you'll always get top-notch audio performance. Cutting-edge, independent digital power supplies for each channel prevent cross-talk interference, ensuring clean, spacious sound. Oversized heat sinks keep the SI-2150 cool even when driving heavy loads, eliminating the need for a noisy cooling fan and guaranteeing silent operation.

Installer-friendly features

Niles knows what it takes to stay competitive in the world of custom installation. That's why their amps include features that make them easy to integrate. You get three separate turn-on modes to bring the amp to life, plus a 12-volt DC control output to activate other devices such as motorized screens and curtains. Independent level controls for each channel allow precise volume matching to the rest of the system, and can also be used to limit volume to prevent speaker damage. Handy cascade audio outputs let you daisy-chain mutiple amps together. And you can even combine its two channels into one to give your speakers more juice — a great option for power-hungry outdoor speakers.

I looked it up through my Sonos receiver to give me more power to outdoor speakers sounds fantastic!

Vince, New Jersey

What's in the Box:

  • Stereo system integration amplifier
  • 6' AC power cord (3-prong IEC plug)
  • 2 Rack-mount ears
  • Installation Guide

Product Highlights:

  • 2-channel amplifier
  • bridgeable high-current design handles unusual and reactive loads with ease
  • power output:
    • 150 watts RMS per channel into 8 ohms (both channels driven)
    • 270 watts RMS per channel into 4 ohms (both channels driven)
    • channels are bridgeable to 550 watts RMS (mono) into 8 ohms
  • cutting-edge digital power supplies (one for each channel to eliminate crosstalk)
  • frequency response: 5-25,000 Hz (-3 dB)
  • signal-to-noise ratio: 102 dB (20-20,000 Hz)
  • total harmonic distortion: 0.2% (20-20,000 Hz)
  • three turn-on modes: music-sensing, voltage trigger, and manual
  • gold-plated binding posts spaced to accommodate dual banana plugs
  • 12-volt control output
  • voltage trigger input accepts 3-24V AC/DC
  • cascade audio outputs let you easily connect additional amplifiers to your system
  • independent right- and left-channel level controls for precise volume matching
  • fanless design with oversized heat sinks for cool, quiet operation
  • DC, short circuit, and overload protection with automatic reset
  • front-panel LEDs indicate Power, Active Status, and Protection Warning for easier troubleshooting
  • detachable AC power cord
  • rack mount ears included
  • weight: 10.7 lbs.
  • 17-1/4"W x 2-1/4"H (including feet) x 14-1/2"D
  • warranty: 2 years
  • Our 60-day money-back guarantee

Niles SI-2150 Reviews

Average Customer Review:

7 Reviews

Powering Extra Speakers

Written by: PatrickE from Washington on November 5, 2015

Crutchfield Customer Review (What's this?)

I purchased this Amp to run three sets of speakers in different rooms. Working with a Denon AVR X2100W receiver and a Niles selector switch I can now listen to TV sound, music and tuner audio in two inside rooms and out on the patio. The Amp works as advertised sending clear sound signals where we want them.

Pros: Compact design, easy to hook up, plenty of power.

Cons: Does get warm, the easy fix is to turn off when not in use.

Powers 10 Speakers in 6 Rooms

Written by: George from Nebraska on October 21, 2015

Crutchfield Customer Review (What's this?)

I bought this to power 10 ceiling speakers in 6 rooms (4 stereo, 2 mono). I connected it to the Zone 3 output of my Onkyo TX-NR737. It senses when there is audio output from the receiver and automatically turns on and off. The sound in very clear. The amp has plenty of power for my configuration. I only needed to set the volume controls at 1/3 of maximum power. This is plenty loud and we usually turn the volume down using the volume controls in each room.

Pros: On sale for a great price.


Great Amp

Written by: Vince from New Jersey on June 22, 2015

Crutchfield Customer Review (What's this?)

I looked it up through my Sonos receiver to give me more power to outdoor speakers sounds fantastic!



First one failed but Crutchfield came to the rescue!

Written by: Velcro Ninja from Las Vegas on August 28, 2013

Crutchfield Customer Review (What's this?)

Using the amp to bi-amp my Polk RTi A9 Floorstanding Loudspeakers. Within the first three weeks the amp failed. I called Crutchfield and performed all of the useful troubleshooting steps that the Tech Support staff offered. Crutchfield sent out a new replacement once it was determined the issue was the amp. I can't say enough about the customer service I have received from Crutchfield, it makes a huge impact on all of my future home audio purchases.

Pros: Nice footprint, worked perfectly before it failed.

Cons: First one failed.

Niles SI-2150

Written by: fisherjohn from long beach island nj on July 6, 2013

Crutchfield Customer Review (What's this?)

does the job




Written by: Mario C from San Jose CA on July 5, 2013

turned out defective and then incompatible with my Marantz SR5007, I was talked into buying it by the staff, never even heard of the brand, not sure why it was even an option for the tech support, so there, I guess do your homework, and don't think Crutchfield will know exactly if its compatible with a ZONE 2 receiver output

Pros: ..........

Cons: if they are so great, why aren't they compatible for the most basic task

Great amp

Written by: Erik from Portland on April 25, 2013

Crutchfield Customer Review (What's this?)

Great amp, lots of power. Hooked up to a connector block and volume control for 4 sets of speakers in multiple rooms. Plenty of power/volume with output levels set to about 30%. Auto on music sensing feature is very nice.

Pros: Features, performance

Cons: Cost


Hands-on research

What's in the box?

Download the Niles SI-2150 manual

  • Stereo system integration amplifier
  • 6' AC power cord (3-prong IEC plug)
  • 2 Rack-mount ears
  • Installation Guide

Product Research


Overview: The Niles Audio SI (System Integration) Amplifiers are designed to power your custom-installed Audio-Video system. They are constructed with the finest materials available, including 1% metal film resistors, high quality capacitors, and oversized heat sinks, that can properly cool the unit without the need for a noisy fan.

Power Output: The SI-2150 stereo amplifier provides 150 watts RMS per channel at 8 ohms, and 270 watts RMS per channel at 4 ohms with all channels driven. When bridged, the output is 550 watts into 8 ohms.

Line Level Input: The amplifier has a single pair of gold-plated stereo RCA input jacks. If you are bridging the amplifier, you can connect a mono source (single RCA) to the left-channel input.

Cascade Audio Outputs: The unit's Cascade Audio Outputs enable you to daisy-chain another amplifier, by connecting the preamp output of the SI-2150 to the input of the second amplifier. The outputs are not buffered, so if you wish to daisy-chain more than 5 Niles SI Amplifiers, you will need a buffered distribution amplifier, such as the Niles AVDA-3.

Speaker Terminals: The amplifier is equipped with 5-way binding post speaker terminals. The terminals will accept single- and dual-banana plugs, pin connectors, spade lugs, and bare wire up to 12-gauge. For most applications, 16- or 18-gauge wire is recommended. For wiring runs longer than 80 feet, 14-gauge wire is recommended.

Multiple Speaker Loads: The SI-2150 is stable into very low impedance loads (minimum impedance is 2.66 ohms in stereo), which means you can safely operate up to three pairs of 8-ohm speakers directly connected to the amplifier. You will need to connect a speaker selector switch if you wish to independently turn on/off connected speakers, or if you wish to connect more than three pairs of speakers.

Independent Level Controls: The SI-2150 has independent left- and right-channel level controls, letting you pre-set the maximum volume, or precisely match the volume to the rest of the system. The controls are located on the rear panel to limit unwanted access.

Turn-on Modes: For convenience, the SI-2150 offers three turn-on modes. Using the 3-way switch on the back panel, you can choose from the following modes:

  • Manual Turn-on: The amplifier is turned on and off using the front panel Master power switch. The automatic turn-on circuitry is turned off. (Switch position: Constant)
  • Music Sense: The amplifier turns on automatically when the presence of an audio signal is detected on either the left or right input. When the audio signal is no longer detected, the amplifier turns itself off after approximately 2 minutes. (The front panel Master switch must be in the On position, and the Turn-on Mode switch position is set to Audio Sense.)
  • External Trigger: The amplifier turns on automatically when a signal is detected at the 3.5mm AC/DC trigger input. Once the Trigger voltage is turned off, the amplifier automatically turns itself off. Voltage triggers can be supplied by a variety of sources, including surround sound processors, video projectors, and automated switchers. The trigger signal must be 3-24 volts AC or DC, 20 mA or greater. (The front panel Master switch must be in the On position, and the Turn-on Mode switch position is set to 3-30V AC/DC Trigger Input.)

12-volt Control Output: In addition to the 12-volt Trigger Input, the SI-2150 can be used to control other devices using 12-volt triggers, such as motorized screens and curtains. When the amplifier is powered on, a 12-volt DC (150 mA) signal is present at the 12V Control Out 3.5mm mini-jack. (Polarity: tip = +)

Rack-mount Ears: The SI-2150 comes with a pair of rack-mount ears to allow you to mount the amplifier in a standard equipment rack. The rack ears attach to the sides of the amplifier chassis using the 4 installed screws. The amp requires only a single rack space (1U) with the feet removed.

Note: A minimum of 7" of free air space must be provided above the amplifier for proper ventilation.

Removable AC Cord: The SI-2150 comes with a 6' detachable, heavy-duty power cord that allows you to unplug it either at the amp or at the wall outlet. The amplifier uses an IEC 3-prong cord. The amplifier features an auto-switching, 110V-230V power supply.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Q & A

Customer Q&A

Crutchfield asked  
Why did you buy this?

Good power in a small box... Also the adjustments for the left and right sill make things easier on installation. [ JOHN  Dec 17, 2015 ]

2 questions already asked

I'm not sure I understand your application Philip. The HK has it's own built-in amplification and does not offer a good way to add an external amp. The Klipsch speakers are a fine match to be powered by either the HK directly or the Niles amp but there's no good way to connect the Niles amp to the HK receiver. I hope that helps! My Bio: [ Ryan  May 06, 2016 ]  Staff
Mark, I have been pleased with my Niles Power amps. I have them paired with a rock speakers which are outside in my backyard. I actually have 3 of them and pair them with the rock speakers and sonos system. They have worked very well. There is a dial on the back that you can limit the amount of power that the amp puts out. I have mine set at 75%, so you could get this amp and then tone it down if your speakers can't handle the full power they put out. I like having more power than I need so that I am not taxing the amp to its max capacity. I think the amp would be fine for you. I hope that helps with your decision. Good luck. All the best, Andy [ Andrew  Apr 08, 2016 ]
I believe this amplifier would be fine for your application. More power is better in that you would be less likely to deliver "clipped" audio signal to your speakers. [ Scott  Apr 06, 2016 ]
Yes, it is safe. The Niles SI-2150 have left and right gain knobs in the back. The amp at my house is moving 2 Outdoors Proficient Audio AW830 without any effort. It also runs super cools with extra large heatsinks. A3 speakers runs at 8 ohms. Hope this helps. [ JUAN  Apr 06, 2016 ]
Hi Mark. I am using this amp to power to Polk A1 speaker w/o any issues. These are rated at 100 watts. The A3 is bigger than the A1 so you should not have any issues. [ HIRAM A  Apr 05, 2016 ]
The amp is a good fit for that speaker set. I have used mine for that same set of speakers and it works well. [ Randal  Apr 05, 2016 ]