Readers who have studied and absorbed Parts 1 and 2 of this article will be fully aware of how the Audio DAC 2000 works. What remains to be discussed is the actual building of the converter, and this is done in this third and final part.POWERSUPPLYAlthough the summary implies that all parts of the digital-to-analogue converter (DAC) have been discussed, this is not entirely true, because the power supply has not yet been described.It was seen in Part 2 of this article that the converter ICs need a symetrical ±5 V supply and that this was derived via regulators IC13 and IC14 from the ±12 V supply line for the analogue circuits. Since it is important to keep the supply lines to the converter ICs as short as possible, the regulators are housed on the DAC board.The receiver section and some other circuits on the DAC board need a single +5 V supply and a symmetrical ±12 V supply. These voltages are produced with the aid of regulators IC15–IC17, which, together with the other components of the power supply, are housed on a separate board, the PSU board.