Niles Audio SI-2100 Stereo Power Amplifier

The Niles SI-2100 is a compact high-current 2-channel Class D power amplifier designed primarily for custom installation and multi-room audio systems, but it has also gained popularity among hi-fi enthusiasts for its strong power delivery, cool operation, and excellent load stability. Built as part of Niles’ Systems Integration Amplifier (SI) range, it offers flexible installation features while remaining capable of serious two-channel performance.

Its compact 1U rack-height chassis, bridgeable architecture, and stable low-impedance operation make it particularly versatile for distributed audio, passive subwoofer duty, or traditional stereo applications.

Specifications

Amplifier Design

• Type: Stereo power amplifier
• Class: Digital / Class D
• Channels: 2
• Bridgeable: Yes

Power Output

• 100W RMS per channel into 8Ω
• 220W RMS per channel into 4Ω
• 400W RMS bridged into 8Ω

The SI-2100 is stable down to 2.66Ω in stereo mode, allowing multiple speaker pairs to be driven safely in distributed systems.

Performance

• Frequency Response:
  5Hz – 25kHz (-3dB)
• Signal-to-Noise Ratio:
  >102dB
• Total Harmonic Distortion:
  0.2% (20Hz – 20kHz)
• Channel Separation:
  >70dB @ 1kHz

Inputs & Outputs

Inputs

• 1 × Stereo RCA input

Outputs

• 1 × Stereo RCA cascade output (for daisy-chaining additional amplifiers)

Speaker Outputs

• 5-way binding posts
• Accepts:
  • banana plugs
  • spades
  • pin connectors
  • bare wire

Control & Integration

• 3 × turn-on modes:
  • Manual
  • Audio sensing
  • 3–24V AC/DC trigger
• 1 × 3.5mm trigger input
• 1 × 12V trigger output (150mA)

These features make it especially useful in automated AV systems and custom installs.

Construction

• Fanless cooling design
• Oversized heatsinks
• Auto-reset protection:
  • DC protection
  • short-circuit protection
  • overload protection
• Auto-switching 110V–240V power supply

Physical Specifications

• Dimensions (W × H × D):
  438 × 56 × 343 mm
• Weight:
  4.9 kg
• Rack Height:
  1U

The SI-2100 has developed something of a cult following because it delivers:

• excellent power-per-dollar
• strong current capability
• cool running performance
• stable multi-speaker operation
• surprisingly good sound quality for a CI amplifier

Community reports often note that the SI series uses Hypex-based Class D modules, which helps explain its solid sonic reputation and ability to drive difficult loads.

While originally designed for installation work, many audiophiles use the SI-2100 in stereo systems due to its strong dynamics and compact footprint.

A versatile high-current stereo amplifier combining installation-friendly features, bridgeable power, and efficient Class D performance for both distributed audio and hi-fi applications.

Condition: Good

Colour: Black

Note: Product does not include original packaging or additional accessories