90%

ATC SIA2-100 Stereo Integrated Amplifier #1

ATC SIA2-100 Stereo Integrated Amplifier

Name: ATC SIA2-100 Stereo Integrated Amplifier
Brand: ATC
SKU: sia2-100
Rating: 4.5 (16 reviews)

View at ATC

Built-in DAC

Headphone Output

Pre-Out

USB Audio

DSD Support

Hi-Res Audio

Overview

Compact in size yet offering high power output and exceptional resolution, this integrated amplifier with on-board DAC is ideally suited to driving ATC’s small and mid-size passive loudspeakers and a very wide range of loudspeakers from other manufacturers. Understated styling makes it easy to integrate with partnering equipment whilst its small footprint occupies very little space in the home. An ideal partner for our CD2 CD Player.

Features

2 x line level analogue inputs.
3 x digital inputs: USB, Coaxial, TOSLINK.
Premium AKM 32-bit DAC.
USB digital input supports up to 384kHz PCM data and native DSD256.*
2 x 100W Discrete MOSFET Output Stage
Headphone amp featuring discrete output stage.
Handmade in England & covered by a 6 year warranty.

*DSD256 support via PC only (up to DSD128 via Mac).

Dealers selling ATC near you

Join us at T.H.E. Show SoCal 2026!

Overall Score 90/100

Nicely Roasted

ATC SIA2-100 Stereo Integrated Amplifier

The ATC SIA2-100 delivers a neutral, transparent and detailed presentation that favours timing and musicality. The 100W Class-AB amp offers nimble pace, punchy drums and refined midband clarity, and images instruments with remarkable precision — traits highlighted by What Hi‑Fi? and Audiophilepure. Its onboard DAC handles high-resolution files (USB up to 32/384, DSD support) and often matches external sources for musical engagement. Construction is solid with a tactile volume control, making it a dependable central component. Listeners seeking honest, analytical playback and excellent imaging will appreciate its strengths; some rivals offer greater weight and scale, but the SIA2-100 stands out for its neutrality and timing.

Audiophilepure

"the result wasn't dramatically superior to the onboard converter, and that, for a £2.5k component, is a decent result."

What Hi-Fi

"ATC’s balanced-sounding stereo amp has plenty going for it, but lacks the all-round appeal of the very best"

Pros

Neutral, transparent and highly detailed presentation that reveals instrument timbre and vocal clarity.
Impressive agility and timing—nimble pace and punchy drums deliver engaging dynamics.
Precise imaging with clear instrument placement and stereo focus.
Solid build and tactile volume control provide a dependable, well‑made user experience.

Cons

USB input can underperform versus other digital inputs, sounding sluggish on some tracks.
Falls short of the ultimate scale and low-end weight offered by some rivals at this price point.
Front-panel proportions and the small display look awkward compared with more refined competitors.

Sound Quality

90/100

Dynamics

89/100

At 100W/Class‑AB expectations, the amp shows impressive agility and pace: reviewers call out punchy drums, nimble bass and a sense of timing, with Audiophilepure describing a "scorching solo" and What Hi‑Fi noting "impressive agility." It does, however, lack the ultimate heavyweight authority and scale of the very top amplifiers at this price, so dynamics are excellent but not reference-class.

Soundstage Imaging

91/100

Both reviews highlight precise instrument placement and excellent imaging — What Hi‑Fi says the ATC "communicates the path and position of all the instruments with impressive precision." The presentation is focused and well differentiated, delivering convincing depth and localization across recordings.

Show Less

Build Quality

86/100

Build is solid and well executed with a reassuringly tactile volume control, though What Hi‑Fi notes the finish and overall slickness fall short of the very best in this segment. The chassis and control feel are robust, but it isn’t a showpiece in terms of industrial design refinement.

Features Connectivity

89/100

Feature set is strong for a traditional integrated: built‑in DAC (USB up to 32/384 and DSD support), optical and coaxial inputs, headphone 6.35mm output, and analogue pre‑amp outs. Missing items are a phono stage and wireless streaming/Bluetooth, but the high‑resolution USB and digital options plus headphone out make this a well‑featured unit overall.

Value for Money

88/100

Reviews present a mixed but generally favorable value picture: Audiophilepure felt the onboard converter and overall performance were impressive for the asking money, while What Hi‑Fi warns that some rivals may better the sound for the price and criticizes the USB performance and looks. Taken together this supports a justified‑premium assessment — good value if you prioritize transparency and build quality, but not an unqualified bargain.