CHORD ELECTRONICS QUTEST DAC REVIEW
July 12, 2019 § Leave a comment
“Every manufactured chip has limitations and generally made to a price point and design criteria. The chip cannot be auditioned before production, and although it is logically and mathematically sound, you have to wonder if they’re designed with the utmost sound quality in mind?
At Chord Electronics, things are done a little differently. Rob Watts’ FPGA (Field Programmable Gate Arrays) approach allows him to design digital circuits with total control over the hardware. So by designing a DAC using FPGA and discrete analog components, it is possible to have increased flexibility over the rigid performance aspects compared to typical off-the-shelf DAC chips.
Watts’ considered approach to ultimate DAC design is to utilise far more complex calculations than was ever thought to be needed, with unheard of long interpolation filters which he designs using what’s known as a windowed-sinc technique. He calculated that a 1,000,000 tap filter (with the number of taps being the indicator of how complex the FIR filter is) is needed to guarantee 16-bit performance from the interpolation filter, a number that was so inconceivably high that many thought that it would be impossible to build. ”