Computer Audio Design CAD 1543 MKII Digital converter

Digital-to-analog converters
Computer Audio Design CAD 1543 Mk II
Computer Audio Design CAD 1543 MKII Digital converter

When Scott Berry brought me the first incarnation of his CAD DAC, I chided him for only including a USB input and not having a removable mains cable: it seemed like single-minded madness. But the 1543, so called because that is the number of the multibit DAC chip it’s based on, proved to be one of the very best converters I had heard, because it had been conceived in such a single-minded fashion. It clearly wasn’t designed for for commercial reasons; it’s far too purist for that. Instead, it was made to deliver the best possible sound from a computer source. Since then Scott has added the CAD CAT (computer audio transport) to his small roster, which proved necessary because a DAC of the 1543’s quality is extremely revealing of the source and, while a laptop can get you so far, it is a long way from a high-end source. The last product prior to the Mk II version of the converter was a USB cable, which features a patented filter to keep noise out of the DAC.

Scott has essentially been building the best possible elements for a digital audio source and refining them; his no compromise approach has been winning him fans across the board, despite the fact that the DAC is not 100 per cent compatible with sample rates above 176.4kHz and the format of the season, DSD, is unsupported. With the introduction of a MKII model you would expect any manufacturer to address such an issue with the latest chipset that could cope with massive sample rates and multiplications of the DSD rate. But that would mean abandoning the 1543 multibit, non oversampling DAC chip; a Philips design from the 1990s that Scott and a few other connoiseurs revere above all others. The continued presence of this number in the name indicates that this has not changed. Instead, Scott has concentrated on reducing high frequency noise within the DAC, thus making it a higher resolution (or, more accurately, less distorted) converter than it was in the first place.

In the time since the original 1543 DAC, Scott has discovered new ways of reducing what he terms, “high frequency energy”, and these techniques have been incorporated into the new converter. Central to this is a material that is designed to absorb RFI and EMI noise and convert it into heat. Scott feels this high frequency energy is the bane of digital audio, so anything that can be done to reduce its presence is beneficial to the end result. The main change to the electronics is in the PCB that supports the DAC chips; in the new PCB, the I2S and USB receivers are positioned alongside the analogue output. This has been redesigned and has four rather than the original’s three layers. It is surrounded by three other boards: the analogue power supply, digital power supply, and mains conditioner. The latter has been modified with new components and serves to filter out the frequencies that Scott considers most damaging.

Another significant change is to the wiring. This is now made with OCC (Ohno Continuous Cast) copper in a custom configuration. The casework remains acrylic as per the original 1543 and continues to have a captive mains cable, now terminated in an Atlas branded 13A plug. The connections are as minimalist as ever – a USB input and a pair of high quality RCA phono output sockets. There is, however, one extra socket on the MKII. This is for the CAD Ground Control, Scott’s latest creation: it’s a passive device housed in more matte black acrylic that is designed to reduce ground noise on any component. In other words, it’s not specific to the 1543 MKII, but can be connected to any audio component and reduce noise on its ground plane.

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