Naim Nait 5si Integrated Amp

Description

Naim Audio’s Nait 5si is one of those amplifiers that makes a strong case for the idea that specifications tell only part of the story. Introduced as the successor to the Nait 5i, the 5si retained the compact, minimalist philosophy that has defined Naim’s integrated amplifiers for decades while adding more power and a number of significant circuit refinements. It delivers 60 watts per channel into 8 ohms—up from 50 watts in the 5i—with the additional output made possible in part by a larger toroidal transformer and an improved power supply. Naim also rates it at 90 watts per channel into 4 ohms.

The Nait 5si is unapologetically an analog integrated amplifier. There is no built-in DAC, phono stage or Bluetooth, reflecting Naim’s emphasis on keeping the signal path focused and uncomplicated. Connectivity consists of four analog inputs, using a combination of RCA and Naim’s preferred DIN connections. A front-panel 6.35mm headphone socket is also provided, and the amplifier includes an AV-bypass mode that allows it to be incorporated into a home-theater system.

Visually, the 5si is quintessential Naim: understated black finish, a substantial aluminum chassis and a simple front panel dominated by the unusually positioned volume control. Four source buttons sit to the right, each illuminated when selected. There is no display and no unnecessary instrumentation. The result is an amplifier that looks more like a serious piece of professional equipment than a lifestyle product.

Inside, however, the 5si received considerably more than a cosmetic makeover. Naim upgraded the power-amplifier components and signal capacitors, while the circuit board and wiring benefited from development work associated with the company’s DAC-V1. The power supply is particularly important to the design, with the toroidal transformer employing separate windings for the amplifier and control electronics.

Sonically, the Nait 5si is characterized by speed, rhythm, dynamics and involvement rather than sheer warmth or spectacular hi-fi effects. Music has a propulsive quality, with strong bass control and an impressive ability to follow complex rhythmic structures. It tends to make the listener concentrate on the performance rather than dissecting the soundstage.

What Hi-Fi? was highly enthusiastic, describing the 5si as one of the best amplifiers available at its price and praising its energetic, musically involving presentation. Stereophile likewise found the amplifier’s physical construction impressive, calling its front panel “strong and handsome” and specifically noting the substantial feel of the controls and connections.

The 5si does have limitations. Its feature set is sparse by modern standards, and listeners wanting streaming, digital inputs or vinyl playback will need separate components. It is also an amplifier whose character and performance depend significantly on speaker matching. But with an appropriate pair of speakers and a good analog source, the Nait 5si remains an unusually engaging amplifier—one that prioritizes musical communication over feature count.

Product Specifications

• Type: Stereo integrated amplifier
• Power output: 60 watts/channel into 8 ohms
• 4-ohm output: 90 watts/channel
• Inputs: 4 analog inputs; 2 DIN and 4 RCA connections
• Headphone output: 6.35mm / ¼-inch jack
• Outputs: Speaker, HDD/line output
• AV bypass: Yes
• Input sensitivity: 170mV
• Input level: Suitable for 2V sources
• Line output: 150mV, 600 ohms
• Power supply: 115/230V, 50/60Hz
• Transformer: Toroidal, with separate windings for amplifier and control electronics
• Dimensions: 17.0″ W × 2.8″ H × 11.9″ D
• Weight: Approximately 15 lb / 6.8 kg
• Design: Aluminum chassis/sleeve with zinc die-cast fascia