http://www.the-ear.net/review-hardware/metrum-acoustics-adagio-dacpreamplifier
"New to the Adagio are Transient DAC Two modules, a further development of the Transient and FPGA architecture used in the Pavane DAC. Inside each module are two 16-bit R2R ladder converters and one FPGA. When a 16 to 24 bit signal enters the module it is split into two sections by the FPGA. The upper bits are passed directly to one of the R2R converters, while the lower bits are raised to the highest level before they reach the second R2R converter. This increase in level is done so as to use the highest voltage on the ladder resistors, moving away from the relativel noisy, low level signal part that exists in all types of converter. Before the output stage the signal level of the second converter needs to be adjusted to the correct level and combined with the original upper part to create the correct output signal. Metrum manipulates the least significant bits (LSB) because lower level irregularities occur, non-linearity arises and digital noise becomes part of the analogue signal with lower level signals. These modules reduce noise by -145dB or more. This might sound simple but it took years to write the algorithms for the FPGA and to develop the Transient DAC Two R2R converters."
Not to stray too off topic though, PS Audio dacs are great, was just wondering what other dacs use fpga processing.