CAD 1543 MKIII DAC

Scott Berry founded Computer Audio Design around a single conviction: that the Philips TDA1543, a 16-bit multibit converter from the late 1980s, sounds more natural than modern delta-sigma silicon when it is fed a clean signal and left to work without oversampling or digital filtering. The original 1543 DAC appeared in 2011; the MKII followed in 2015 and the MKIII went into production in 2025. The architecture is unchanged in principle, a resistor-ladder non-oversampling design with a passive output stage, and everything around it has been rebuilt.

The MKIII runs twenty TDA1543 chips on a four-layer board, up from sixteen, which raises the output and lowers the noise of the paralleled array. Five independent, fully discrete power supplies replace the previous arrangement, each fed by an oversized EI transformer rather than a toroid, each with its own discrete linear regulator, a custom choke in the rectification and 110,000 µF of Japanese audio-grade reservoir capacitance in total. The passive output stage uses Duelund Coherent Audio capacitors and US-made resistors built to CAD's specification, and the internal wiring is custom UP-OCC copper.

The single input is asynchronous USB. CAD implements it with a CPLD rather than an XMOS controller, which draws less current and radiates less noise, and clocks it with new oscillators specified at -100 dBc/Hz at 10 Hz. Three EI transformers and three discrete supplies power the USB interface alone, the DAC never draws the 5 V from the USB cable, and galvanic isolation keeps the server's ground current away from the converter chips. The case is 10 mm laser-cut acrylic, chosen for its mechanical and electrical behavior, lined with the EMI and RFI materials CAD uses in its Ground Controls, and standing on Krion feet.

The 1543 MKIII plays PCM to 176.4 kHz and nothing else; there is no DSD, no MQA and no filter menu. It works with most Linux-based servers, including Innuos, Aurender, Melco, Antipodes and Roon cores, and with Windows servers such as Taiko and Wadax after installing CAD's driver. Jason Kennedy reviewed it for The Ear in April 2025 and summed up the sound in one word, natural. The pairing CAD itself shows is with its own USB II-R cable and a Ground Control on the server.