ATC SIA2-100 and CD2

Probably best known for its loudspeakers, ATC has also made a small range of electronics for many years. As many of the speakers it sells are active models, the company knows its way around amplifiers and has taken this expertise and constructed a range of integrated, pre and power amps that have more recently been augmented by the inclusion of digital decoding.

The duo you see here are the latest arrivals in the range and are in keeping with the company’s design philosophy, while also being rather different from the norm – boasting a three-quarter width casework. The CD2 CD player is ATC’s first attempt at pure source equipment and is designed to match the specification of the SIA2-100 integrated amp.

At first glance, the SIA2-100 (Stereo Integrated Amplifier, 2 channels, 100W) is fairly conventional. In keeping with ATC’s design philosophy, it features a separate power supply for the pre and power amp sections and the output stage is comprised of MOSFET devices in a common source configuration. This is all fairly traditional practise, but it should mean that the SIA2-100 can handle most loudspeakers with ease.

As well as offering a pair of RCA stereo analogue inputs plus another on a 3.5mm jack via the front panel, it also supports coaxial and optical digital inputs and has a USB-B port that can handle files up to 32-bit/ 384kHz PCM and DSD256 (DSD128 via Mac) through its AKM DAC.

The CD2 also uses an AKM DAC, but partners it with a TEAC transport mechanism and forgoes digital inputs of its own (as they’re already on the amp). You do get balanced outputs, though, presumably to allow the CD2 to work with suitably equipped ATC amplifiers and preamps. The internals of the CD2 are also fastidiously designed. There are nine power regulators in the circuit to ensure accurate delivery and every section of the signal path is as short as possible.

This is admirable, but operationally the CD2 is rather quirky. There are five hard buttons on the front for quick control, but otherwise it shares a remote with the amplifier. This is convenient, but operationally feels odd. There is no marked pause button (you press play again on either the player or remote) and pressing the large button on the remote that looks like a track skip button will in fact scan the track currently playing. It all works perfectly once you are wise to it, but takes a little getting used to. The amplifier does without direct input selection, instead there is a single button that cycles through the inputs. As there aren’t many inputs it’s bearable, but not as good as having dedicated source buttons.

Both units are handsome and well made. The slight curve to the side cheeks is a rare flourish that looks elegant and the rest of the product feels extremely well assembled. I especially like the arrangement of the connections across both units. Nothing feels crowded or poorly located and it makes connecting up both components very easy.

Sound quality
I initially focus on the SIA2-100. Connected to Bowers & Wilkins hugely revealing 805 D3 standmount and an SOtM sMS-200 Neo network audio player (HFC 449) running into the USB port, it impresses from the off. With a background in professional audio, ATC has never been about anything other than tonal accuracy and the new amp doesn’t let the side down. Familiarity by Punch Brothers from The Phosphorescent Blues album feels utterly and unambiguously real. The pared-back instrumentation alternates with big but brief orchestral interludes that explode into life and vanish as fast as they appeared. Lead singer Chris Thile’s vocals have the weight and space they need to be the soul focus of your attention.

One consistent aspect of the performance is that the SIA2-100 doesn’t seek to modify the material it plays. This does mean that if the equipment it is partnered with tends towards being soft or uninvolving, it won’t do anything to correct it, but with the composed yet joyous B&W 805 D3 the effect is to let the speaker lead the character of the presentation. This is not to suggest it is completely neutral, though. Via the USB-B port, there is the slightest sense of the AKM DAC making itself felt. In comparison with the more commonly encountered ESS DACs, it feels tonally sweeter, trading a little detail for a refinement that isn’t always present with the Sabre family.

None of these qualities come at the expense of sounding ballistic when called upon to do so. The pulsating digital fury of Orbital’s Monster’s Exist sees the duo in its element. The assurance with which it hammers through the crescendos of the track is notable and while there are some rivals that can feel a little lighter on their feet, the composure – even at anti-social levels – impresses. There are notionally more powerful amplifier designs available at a similar price, but the ease with which you can exploit the power that the ATC makes available takes some beating.

Given that the CD2 is built around similar decoding hardware, it should not come as much of a surprise to find that the performance mirrors the amplifier’s digital section. There are some intriguing caveats, however. Listening to Santigold’s Master Of My Make Believe with the CD connected to both the RCA and coaxial input of the SIA2-100, the riotous Go! has a little more bass weight and force via the CD2’s own decoding than when using the amplifier. It’s not a night and day difference, but it’s certainly worth using an analogue connection out of the CD2 if you can.

Once again, the overall balance of the CD2 is clearly targeted towards a calm and reasoned take as to what is on the CD, but if that extends to something fun it has little trouble reproducing it. The euphoric Waiting For The 7:18 by Bloc Party is delivered with all of its joy firmly intact. The balance between Kele Okereke’s heartfelt lyrics and the stomping urgent percussion is beautifully judged and notable because this disc is not a recording for the ages. The CD2 manages to open it out and deal with some of the rougher edges without compromising the feeling you are listening to an unembellished version of the music.

As a duo it’s greater than the sum of its already capable parts. The forgiving element to the CD2’s presentation means it will handle a collection of rough diamonds with an even handedness and consistency that rivals can lack. It also proves a happy partner for a vinyl front end and my Michell GyroDec and Cyrus Phono Signature MM/MC phono stage (HFC 408) setup, maintains its character and benefits from the neutral presentation and effortless headroom of the SIA2-100 integrated amplifier.

Even if you aren’t looking to buy the ATCs as a pair, individually they have much to offer. The SIA2-100 amp and SOtM sMS-200 Neo networked audio player partnered up together comes in at a price that keeps many similarly specified all-in-one setups honest, the SOtM giving the amp the streaming functionality it otherwise lacks. The CD2 silver disc player is arguably more compelling as a solo purchase. It has a genuinely lovely sound that flatters discs that need to be flattered and gives free reign to those that don’t. As a pair, this is a fabulous combination that manages to thrill and cosset in equal measure. ATC doesn’t introduce electronics very often, but these two are worth the wait and worthwhile seeking out. ES    

Product: ATC SIA2-100/CD2
Price: £2,500/£1,500
Origin: UK
Type: Integrated amplifer/CD player
Weight: 9.7kg/4.2kg
Dimensions: (WxHxD) 315 x 113 x 315mm/ 315 x 77 x 315mm

● Quoted power output: 2x 100W (8ohm)
● Inputs: 2x stereo RCAs; 1x coaxial; 1x optical; 1x USB-B port (amp)
● Outputs: 1x stereo RCAs; 1x stereo XLRs; 1x coaxial; 1x optical (CD player)

Read the full review in November 2019 issue 455

ATC Loudspeaker Technology Ltd.
01285 760561