ATC SIA2-100 & CD2 > Review in ON-mag.frBlog Post

Inside: it's solid
Under the hood of the ATC CD2, the playback mechanism is a model specifically adapted to Hifi and not a computer model. Note the presence of a toroidal power supply transformer of significant dimensions. The conversion is provided by a 32-bit/768 kHz type AKM chip ( AK4490EQ ). The output stages are of symmetrical topology, all in surface components and, what is more, discrete since with real transistors, without op amps.
The ATC SIA2-100 is advertised for 2 x 100 watts into 8 ohms. The internal layout of its circuits is surprising. The power stages and their power supplies are mounted upside down under a large, solid aluminum finned heatsink. Arranged symmetrically, they operate from a pair of Mosfet transistors ( Renesas 2SJ352 and 2SK2221 models) working in push-pull and class A/B on each channel. Their toroidal power transformer is impressive (10 cm in diameter and almost 7 cm high). Coming from the English specialist Carnhill , it is followed by four filtering capacitors, installed two by two as close as possible to the power stages of 10,000 µF at 80 V each.
A second Carnhill transformer, smaller and nevertheless substantial (6.5 cm in diameter by 3 cm high), is responsible for supplying the other sections. Just like on the CD player, the preamplification ones are in discrete and surface components while the converter is an AKM AK4490EQ. As for the USB interface, it is a Hi-res Amanero Combo384 model . Finally, the volume potentiometer is a motorized double-cage Alps.
The construction of these two electronics is very clean and serious. It should be noted that it is provided in the brand's workshops in Gloucestershire, England. At ATC, all products (speakers and electronics) are designed to be easily repairable and the manufacturer's warranty is 6 years.

Listening: it's solid too
Listening to the ATC SIA2-100 we find the characteristic features of a good amplifier with Mosfet transistors. Its balance is relatively warm. The midrange has color and a nice texture. The highs are biting and very lively. The sound stage is particularly deep while giving a very good feeling of presence and proximity, especially on vocals. We appreciate the dynamics, the nervousness of the restitution. This ATC stereo integrated has temperament and energy to spare. Its basses in particular are generous and of an excellent articulation. The manufacturer recommends the SIA2-100 to power compact speakers. We also found it compelling paired with beautiful columns. True to the image of the English brand, it delivers a solid, muscular sound,
The ATC CD2 player also favors expressiveness rather than cold and surgical analysis. We find with him the lively and energetic character of the amplifier, but in a slightly calmer and more sedate version. Associated with the latter, it brings very beautiful nuances to the midrange as well as a beautiful yarn and opening in the treble. With it, you can easily measure the gap between the CD-Audio, which is now a fully developed format, and the compressed streams that some online music platforms still serve. Its restitution blends very well with that of the SIA2-100.
The two devices together made us want to dive back into old recordings, including some of our "guilty pleasure" music, as they say on the " Quotidien " show. For example, we listened again from start to finish to the "Ultimate" compilation on three Audio-CDs of music from the "Miami Vice" series . Yes Yes ! This is proof that listening to these two ATC electronics makes you feel good.

In summary
There's nothing revolutionary about this 2 x 100 watt stereo integrated amplifier and CD-Audio player. However, the ATC SIA2-100 and the ATC CD2 are designed with extreme care, based on safe and proven technical solutions, then built according to the rules of the art in England. Their sound performance is solid and they are driven by an energetic musicality that makes them very pleasant to listen to.
- Pierre Stemmelin, ON-mag.fr

ATC SIA2-100
ATC CD2
ON-mag.fr