The Formula DAC is the first in the aqua – acoustic production to show a proprietary D/A conversion system, that they have named Optologic DAC. This conversion system follows the same multibit technology (already used in the previous DACs such as La Voce and La Scala) but with a discrete R2R resistors ladder instead of Burr Brown PCM1704 dacs.
Galvanic and magnetic isolations are implemented between the FPGA and the four branches of the R2R ladder converter. This creates complete isolation of all digital circuitry – including the clock – from the analogue section for a pure clean ground plane. It also plays the main role in the differential management of the R2R ladders, “achieving perfect symmetry between the counter-phase halves”.
The Formula Dac uses no digital filter or any other compensation, relying instead on attention to each sub circuit. The analogue and digital power supplies are executed purely discretely by extensive use of BJT, Mosfet, Jfet and ultra-fast diodes. Passive parts were selected not just for the best sonic result but also for their top quality, longevity and reliability. With the exception of six superior quality electrolytics, all other caps are Tantalum, solid-polymer OS-CON and double-metalized MJP. The signal path itself is direct-coupled and free of all capacitors. The two output stages (one single-ended, one transformer-coupled balanced) use discrete BJT and JFet with metal-film resistors. All the electronics parts show an ultra low RF noise.