Installation

Turn-On Modes

The SI-2125 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-2125 on and off.

Constant - The auto turn-on circuitry is off. The front panel master power switch operates the amplifier. In is “On”, out is “Off”.

Audio Sense - The master switch on the front panel must be in the “On” position. The amplifier is off when there is no audio signal present at either the left or the right input, but the sensing circuitry is on. The turn-on sensing circuitry looks for a tiny amount of audio signal present at any of the audio inputs. If it detects a signal, the amplifier is turned on. Once the audio signal stops, the sensing circuit waits two minutes, then turns the amplifier off.

3-30 Volt AC/DC Opto-Isolated Voltage Trigger - The master switch on the front panel must be in the “On” position. The amplifier is off when there is no 3-30V AC or DC voltage detected at the trigger input. Once the sensing circuitry detects a voltage, the amplifier is turned on. Once the voltage stops, the sensing circuit instantly turns the amplifier off. Voltage triggers can be supplied by Niles automated switchers, some video projectors, some surround sound processors, or something as simple as a 16 volt AC wall adapter plugged into the switched outlet of your stereo receiver. Do not use a DC wall adapter. The long discharge time of the DC adapter’s filter capacitor will delay the turn-off of the amplifier.

If you are using a wall adapter or external power supply to provide the trigger, it doesn’t have to be very large (a minimum current capability of 2.5 milliamps for a 3 volt trigger increasing up to a minimum of 38 milliamps for a 30 volt trigger).

SI-2125 specifications

The Niles Audio SI-2125 is a versatile and powerful amplifier designed to meet the demands of modern audio systems, whether for home theater setups or multi-room audio solutions. Offering robust performance and user-friendly features, it stands out in the crowded field of amplifiers.

At the heart of the SI-2125 is its high-power output capability, delivering 125 watts per channel at 8 ohms. This ensures that it can drive a wide range of speakers, providing clean and dynamic sound that enhances the listening experience. The amplifier operates efficiently, allowing it to run cool, reducing the risk of overheating during extended use.

One of the standout features of the SI-2125 is its versatile connectivity options. It comes equipped with multiple input options, including both balanced XLR and unbalanced RCA connections. This flexibility enables easy integration into various audio setups, whether it’s a dedicated home theater system or a more extensive multi-zone audio installation. The amplifier also includes a trigger input for automatic power on/off, which simplifies operation and enhances convenience.

The SI-2125 incorporates high-quality components that contribute to its impressive sound quality. It features a toroidal transformer, which is known for its efficiency and low electromagnetic interference, resulting in a cleaner sound. The amplifier also utilizes a distinctive Class AB design, which balances the advantages of both Class A and Class B amplification, providing ample power while maintaining excellent audio fidelity.

Another noteworthy characteristic of the SI-2125 is its robust build quality. The amplifier comes housed in a durable chassis, designed to minimize vibrations and protect the internal components. This not only enhances longevity but also helps maintain the integrity of the sound. The front panel features a sleek design with clearly labeled controls that provide easy access to essential functions, including volume control and input selection.

In addition to performance, the SI-2125 also supports a range of advanced features aimed at enhancing usability. This includes a unique feature set that accommodates various speaker configurations, allowing users to optimize their audio experience to suit their specific preferences and room acoustics.

Overall, the Niles Audio SI-2125 is an exceptional choice for anyone seeking a high-performance amplifier that combines power, versatility, and ease of use. Its impressive specifications and thoughtful design make it an ideal addition to any serious audio setup, ensuring that listeners can enjoy their favorite music and movies with remarkable clarity and fidelity.