ATC SIA2-100 Integrated Amplifier
Probably what everyone who already owns a pair of SCM11 or SCM19’s has always been dreaming of. ATC have announced a new ‘baby’ integrated with digital inputs, promoted as Dac, Pre and Power all in one.
We were actually lucky enough to see some of this work in pre production when we visited ATC last year, and it’s incredibly exciting to see this finally ready for launch at Bristol.
As always, as an engineering company, the new products from ATC are thoroughly thought through and with attention paid to every detail. More information and listening impressions to follow shortly.
The SIA2-100 integrated amplifier/DAC has been engineered to partner the CD2 as a smartly compact music separates system, and all passive stereo loudspeaker pairs. It is a versatile one-box design for D/A conversion and pre/power amplification duties specified to generate 2 x 100W (continuous into 8 ohms). The SIA2-100 incorporates 2 pairs of stereo line level inputs on RCA phono sockets, together with a front panel mounted 3.5mm jack socket input, a digital SPDIF optical Toslink input, a digital SPDIF coaxial input on an RCA phono socket, and a USB digital audio input on a USB B socket. There is a single pair of stereo power amplifier outputs on 4mm binding posts, a stereo line level output on RCA phono sockets, and a front panel mounted headphone output on a 6.35mm/0.25″ jack socket.
Input selection is achieved via a front panel push button, and output volume adjustment is via a precision Alps potentiometer. All SIA2-100 functions are duplicated on the ATC remote control handset supplied. Both the CD2 and SIA2-100 chassis are constructed to be heavy, rigid and well damped with precision machined 12mm aluminium front panels finished in brushed and anodised ‘titanium’ silver.
Rigorous measures are taken to reduce noise and distortion in the SIA2-100 integrated amplifier/DAC. Its power amplifiers use the circuit topology which has been revised and refined over the past 30 years for all ATC power amplifiers. Lateral Mosfets are deployed in a common source configuration to provide very low distortion together with a wide frequency response. A peak limiter is included to protect the loudspeaker drivers in the event of an overdrive. To reduce intermodulation and cross-talk aberrations there are separate power supplies for the pre-amplifier and power amplifier sections.
ATC’s discrete analogue design and use of multiple local power supply regulators provides the optimum operational platform for the SIA2-100’s AKM onboard DAC and USB receiver. The USB input will handle PCM sample rates from 44.1 kHz to 384 kHz, with word lengths to 32 bits, and also decode DSD sources at 2.822 MHz (Single rate, DSD64), 5.644 MHz (Double rate, DSD128). All inputs, analogue and digital, achieve distortion figures below 0.001%.
The SIA2-100 incorporates a headphone amplifier and a 3.5mm auxiliary input with higher sensitivity, better suited to interfacing with portable audio devices. Both circuits have been designed to deliver the lowest levels of noise and distortion. The headphone amplifier is biased in class A and is specified to drive a range of headphones from 32 to 600 ohms.