Uncompromised in every respect, La Diva cd transport is the culmination of aqua’s R&D in the areas of electronic and mechanical engineering. The DAC Formula xHD comes with the Optologic R2R conversion system.
Both units are in excellent condition.
MRP of the La Diva CD Transport is Rs. 5,90,000
Now offered at Rs. 3,50,000.
MRP of the Formula xHD DAC is Rs. 12,00,000
Now offered at Rs. 6,50,000
Aqua believes that the more musical D/A conversion system is based on the circuit usually identified as "resistor ladder".
This technology has been substituted in the mass-market by the so-called sigma-delta converters.
The sigma-delta converter is a near-completely digital circuit and for this reason it can be can be integrated on silicon and produced at low-cost.
A quality resistor ladder DAC instead uses a circuit based on a set of high precision discrete resistors: at least 2 resistor banks, one for each stereo channel.
The Formula DAC is the first in the aqua’s production to show a proprietary D/A conversion system, that we name Optologic.
The signals sent to the resistor ladders are generated by a proprietary digital circuit, implemented inside an FPGA (Field Programmable Gate Array).
Formula has a sign-magnitude converter structure, and this requires not two but four 24 bit resistors banks, each one made of very low tolerance discrete resistors.
In order to separate the digital section from the sensitive analog circuits, 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 clean, noiseless 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 result is the highest tonal contrast and naturalness.
More information here.