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Niles SI-2150

Stereo power amplifier

Item # 190SI2150

California customers:
Please click here for your Proposition 65 warning.

In stock

About 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.

Product highlights:

  • 150 watts per channel into 8 ohms (20-20,000 Hz) at 0.2% with 2 channels driven
  • 270 watts per channel into 4 ohms
  • channels are bridgeable to 550 watts RMS (mono) into 8 ohms
  • bridgeable high-current design handles unusual and reactive loads with ease
  • 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
  • MFR # FG01703

What's in the box:

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

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More details on the Niles SI-2150

Stacey B.

Features & specs

Number of Channels 2
Power Output per Channel (8 ohms) 150
Power Output per Channel (6 ohms) ---
Power Output per Channel (4 ohms) 270
Frequency Response 5Hz-25kHz
THD 0.2%
Minimum Impedance 2.67
Bridged Power per Channel 550 watts
Speaker Outputs 2
THX Certification No
Width (inches) 17-1/4
Height (inches) 2-1/4
Depth (inches) 14-1/2
Weight 10.7 pounds
Parts Warranty 3 Years
Labor Warranty 3 Years
Inputs & Outputs
Number of Inputs 1
Input Type RCA
Level Controls Yes
Speaker Connectors 5-way binding post
The Niles SI-2150 replaces these items:

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.

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Customer Q&A

5 questions already asked

can one stack these power amps on top of each other safely? I see it has rack mounted ears, but I don't have a rack....just the space to stack a few on top each other if deemed safe.
[ Patrick  Apr 22, 2021 ]
3 answers
Yes you can,cIf you place a AC Infinity, Aircom S8(rear air exit) or S10(front air exit) cooling fan system on top of each power amplifier. They'll run you about $100 each for the S8, or S10 unit. Enter
[ Ron  Jun 26, 2021 ]
They need 7 inches clear above them, and 2 inches clear below them, or else they overheat and shut off, even with no music playing. so you can stack them, but leave at least 7 inches between them.
[ JAMES  Apr 23, 2021 ]
No, I would not. You would want to have room for the ventilation on the top of the unit.
[ Scott  Apr 22, 2021 ]
Can I connect to a single speaker (mono)? I have an outdoor single speaker.
[ Robert  Jun 19, 2020 ]
8 answers
Yes . But the it would blow it
[ Mark  Jun 23, 2020 ]
Pretty sure you can, yes.
[ CHRISTOPHER  Jun 21, 2020 ]
I'm sure you can but you'd be pulling off one channel
[ JOE  Jun 20, 2020 ]
Yes, and you can bridge the Niles to a mono mode to get even more power (550 watts) to your outdoor speaker system so you'll have all the power you need if you want to add more speakers. The instruction manual explains how to set this mode. I'm very happy with the niles amp which drives my Boston Acoustic front speakers of a 9.2.4 Theater system.with a Denon 6300 receiver. The sound and volume are outrageous.
[ MW  Jun 19, 2020 ]
yes. just use one set of terminals. i'm guessing you could also set it to bridge mode, in which case the 4 terminals for 2 speakers, go down to 2 terminals and bumps up the horsepower. it details this in the instructions. good luck
[ Jason  Jun 19, 2020 ]
I believe you would be able to. Will probably have to change the settings in your receiver though? Might be more receiver dependent.
[ DAVID  Jun 19, 2020 ]
yes, in bridged mode, it will be.
[ Derek  Jun 19, 2020 ]
It is bridgeable to 550 watts RMS into an 8 ohm speaker ( mono )
[ M  Jun 19, 2020 ]
Can I connect to my denon avr7200WA?
[ Mathew Chan76  Jul 13, 2017 ]
3 answers
I would think so if your dennon avr7200WA has a line out, looking at the line outputs on the dennon the only one that makes sense is the sub woofer line out. You could run the Niles in a "bridge mode" and drive a sub woofer.
[ Scott  Jul 15, 2017 ]
you should be able to, no problem Class 2 and RCA jacks on the Niles. I have 2 of them daisy chained to a Onkyo AV Reciever
[ DAVID  Jul 14, 2017 ]
Yes, you can connect from one of the pre-output of you receiver and this amplifier serve as one of your surround channel. Make sure yo connect the remote start from your receiver to this amplifier to auto turn on this amplifier whenever you turn on your receiver. Check the instruction of your receiver how to connect an external amplifier.
[ Robert  Jul 14, 2017 ]
Would this amp work well with Klipsch KF28s and a Harmon Kardon HK3490 receiver?
[ Philip  May 03, 2016 ]
1 answer
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
I have a polk A3 speakers that can handle 20-150 watts per channel. Would this amp be safe to use at 150 watts per channel or use a 100 watt channel amp?
[ MarkG  Apr 05, 2016 ]
5 answers
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 ]

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